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You searched for +publisher:"University of Illinois – Urbana-Champaign" +contributor:("Yang, Hong"). Showing records 1 – 26 of 26 total matches.
University of Illinois – Urbana-Champaign
1. Ibrahim, Malek Yahia Saleh. Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction.
Degree: MS, Chemical Engineering, 2015, University of Illinois – Urbana-Champaign
► Catalytic conversion of ethanol through the Guerbet reaction to higher carbon number molecules allows efficient transformation of biomass to liquid fuels and commodity chemicals. A… (more)
▼ Catalytic conversion of ethanol through the Guerbet reaction to higher carbon number molecules allows efficient transformation of biomass to liquid fuels and commodity chemicals. A selective and stable heterogeneous catalyst is required to render this conversion possible in an economic way. The reaction was found to proceed through two parallel mechanisms on basic magnesia where acetaldehyde, formed from ethanol dehydrogenation, can either couple with itself or with adsorbed ethoxide to form new carbon-carbon bonds and the ethanol to acetaldehyde pressure ratio was found to determine which of these two mechanisms predominates. Amphoteric titania, and acidic alumina were found to have very low ethanol dehydrogenation activity and can only catalyze the Guerbet reaction through the acetaldehyde self-coupling mechanism. Strong acidic sites were found to catalyze alcohol dehydration while strong basic sites were found to catalyze esterification and show poor stability under humid conditions. Mild acid-base sites on titania were found to selectively catalyze acetaldehyde aldol condensation and exhibit high stability under humid conditions. To overcome the low dehydrogenation activity of titania, addition of a metallic function was proposed. Among several metals tested, copper was found to be the most selective catalyst for dehydrogenation either as unsupported powder or supported nanoparticles. A synergetic effect was obtained from deposition of the copper nanoparticles on the titania surface since it was found to facilitate product desorption, a step that was found to be the rate limiting for acetaldehyde aldolization. Supported copper nanoparticles were found to catalyze the undesired alcohol esterification reaction. To suppress this side reaction, alloying copper with gold and promotion with chromium and potassium were found to be beneficial. A hybrid sequential-simultaneous reaction configuration was proposed to allow preliminary alcohol selective dehydrogenation on a monofunctional catalyst followed by simultaneous dehydrogenation, aldolization, and product hydrogenation on a bifunctional catalyst. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%22%29&pagesize-30">Kenis, Paul (committee member).
Subjects/Keywords: Ethanol; bifunctional catalyst; metal oxide; acid base; Guerbet; aldol condensation; butanol; biodiesel; titanium oxide; supported copper nano particle
Ibrahim, M. Y. S. (2015). Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction . (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/88973
Ibrahim, Malek Yahia Saleh. "Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction." 2015. Thesis, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/88973.
Ibrahim, Malek Yahia Saleh. "Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction." 2015. Web. 22 Jan 2020.
Ibrahim MYS. Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/88973.
Ibrahim MYS. Design of heterogeneous bifunctional catalyst for upgrading bioethanol through the Guerbet reaction. [Thesis]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/88973
2. Yin, Xi. Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology.
Degree: PhD, Chemical Engineering, 2015, University of Illinois – Urbana-Champaign
► Nanoparticles with well-defined morphology and composition have been studied extensively for their applications in catalysis, energy conversion, and beyond. The unique properties of nanocrystals often… (more)
▼ Nanoparticles with well-defined morphology and composition have been studied extensively for their applications in catalysis, energy conversion, and beyond. The unique properties of nanocrystals often highly depend on their shape, size, and composition. Therefore, control of morphology is essential in the development of nanocrystal-based materials. Design of nanocrystals, however, is still difficult in solution-phase synthesis, largely due to insufficient knowledge of the controlling parameters for the synthesis. For metal nanoparticles, the interactions between metal ions and commonly used ligands in solution-phase synthesis are still not clear, nor are the effects of these interactions on the formation of metal nanocrystals. It is crucial to improve our understanding of the formation mechanisms of metal nanocrystals in order to produce nanocrystals with controlled morphology. This dissertation focuses on the metal ion–ligand interactions and the effects of these interactions on the formation of metal nanocrystals during solution-phase synthesis. Formation of metal ion–ligand complexes were investigated for the synthesis of Pd and Pt nanocrystals. Structures of metal–ligand intermediates that formed were identified using single-crystal X-ray diffraction, mass spectrometry, and UV–vis spectroscopy. Two-dimensional multilayered Pd nanosheets, Pt nanocubes, and Pd nanoplates with controlled morphology were synthesized. The adsorption of metal intermediates and ligands on Pd surfaces was studied using density-functional theory (DFT) calculations. The effects of metal ion–ligand interactions on the formation kinetics of Pt and Pd nanocrystals were analyzed quantitatively. The experimental data show that the metal ion–ligand interaction affected the synthesis of metal nanocrystals through the formation of metal–ligand intermediates, which controlled the anisotropic growth and formation kinetics of metal nanocrystals. These results provide molecular level understanding of the formation mechanism of metal nanocrystals, indicating that design of molecular precursors is an important factor in controlling the morphology of metal nanostructures. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G%22%29&pagesize-30">Seebauer, Edmund G (committee member), Champaign%22%20%2Bcontributor%3A%28%22Guironnet%2C%20Damien%22%29&pagesize-30">Guironnet, Damien (committee member), Champaign%22%20%2Bcontributor%3A%28%22Murphy%2C%20Catherine%20J%22%29&pagesize-30">Murphy, Catherine J (committee member).
Subjects/Keywords: Nanoparticle; Metal ion; Ligand; Precusor; Molecular design; Growth kinetics; Formation kinetics; Palladium (Pd); Platinum (Pt); Nanosheets; Nanoplates; Nanocubes
Yin, X. (2015). Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/89171
Yin, Xi. "Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/89171.
Yin, Xi. "Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology." 2015. Web. 22 Jan 2020.
Yin X. Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/89171.
Yin X. Effects of metal ion–ligand interactions on the synthesis of metal nanostructures with controlled morphology. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/89171
3. Xu, Qingxing Noel. Coaxial double-walled microspheres for drug and gene delivery applications.
Degree: PhD, 0300, 2014, University of Illinois – Urbana-Champaign
► Polymeric double-walled microspheres were developed by coaxial electrohydrodynamic atomization (CEHDA) and precision particle fabrication (PPF) techniques. Here, we focus on double-walled microspheres consisting of a… (more)
▼ Polymeric double-walled microspheres were developed by coaxial electrohydrodynamic atomization (CEHDA) and precision particle fabrication (PPF) techniques. Here, we focus on double-walled microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(D,L-lactic acid) (PDLLA) or poly(L-lactic acid) (PLLA) shell layer. The first study involves bridging the experimental work on the fabrication of double-walled microspheres from CEHDA and the simulation work on the generation of compound droplets from the same process. Process conditions and solution parameters were investigated to ensure the formation of double-walled microspheres with a doxorubicin-loaded PLGA core surrounded by a relatively drug-free PDLLA shell layer. Numerical simulation of CEHDA process was performed based on a computational fluid dynamics (CFD) model in Fluent. The simulation results were compared with the experimental work to illustrate the capability of the CFD model to predict the production of consistent double-walled microspheres. The second study involves drug release and degradation behavior of two double-walled microsphere formulations consisting of a doxorubicin-loaded PLGA core surrounded by a PDLLA shell layer. It was postulated that different molecular weights of the shell layer could modulate the erosion of the outer coating and limit the occurrence of water penetration into the inner drug-loaded core on various time scales, and therefore control the drug release from the microspheres. For both microsphere formulations, the drug release profiles were observed to be similar. Interestingly, both microsphere formulations exhibited occurrence of bulk erosion of PDLLA on a similar time scale despite different PDLLA molecular weights forming the shell layer. The shell layer of the double-walled microspheres served as an effective diffusion barrier during the initial lag phase period and controlled the release rate of the hydrophilic drug independent of the molecular weight of the shell layer. The third study involves designing and evaluating double-walled microspheres loaded with chitosan-p53 nanoparticles (chi-p53, gene encoding p53 tumor suppressor protein) and/or doxorubicin in the shell and core phases, respectively, for combined gene therapy and chemotherapy. The microspheres were monodisperse with a mean diameter of 65 to 75 μm and uniform shell thickness of 8 to 17 μm. The encapsulation efficiency of doxorubicin was significantly higher when it was encapsulated alone compared to co-encapsulation with chi-p53. However, the encapsulation efficiency of chi-p53 was not affected by the presence of doxorubicin. As desired, chi-p53 was released first, followed by simultaneous release of chi-p53 and doxorubicin at a near zero-order rate. Next, the therapeutic efficiencies of doxorubicin and/or chi-p53 in microsphere formulations were compared to free drug(s) and evaluated in terms of growth inhibition, and cellular expression of tumor suppressor p53 and apoptotic caspase 3 proteins in human… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Kong%2C%20Hyun%20Joon%22%29&pagesize-30">Kong, Hyun Joon (committee member), Champaign%22%20%2Bcontributor%3A%28%22Xie%2C%20Jianping%22%29&pagesize-30">Xie, Jianping (committee member), Champaign%22%20%2Bcontributor%3A%28%22Tong%2C%20Yen%20Wah%22%29&pagesize-30">Tong, Yen Wah (committee member).
Subjects/Keywords: Drug Delivery; Double-Walled Microspheres; Drug; Gene
Xu, Q. N. (2014). Coaxial double-walled microspheres for drug and gene delivery applications . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/49760
Xu, Qingxing Noel. "Coaxial double-walled microspheres for drug and gene delivery applications." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/49760.
Xu, Qingxing Noel. "Coaxial double-walled microspheres for drug and gene delivery applications." 2014. Web. 22 Jan 2020.
Xu QN. Coaxial double-walled microspheres for drug and gene delivery applications. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/49760.
Xu QN. Coaxial double-walled microspheres for drug and gene delivery applications. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/49760
4. Pan, Yung-Tin. Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance.
► Bimetallic nanocatalyst often shows enhanced performance where the key lies not only on the overall composition but more importantly, is related to the specific atomic… (more)
▼ Bimetallic nanocatalyst often shows enhanced performance where the key lies not only on the overall composition but more importantly, is related to the specific atomic arrangement of the two metal elements on the and near surface regions. In order to make the most out of bimetallic nanocatalyst, it is important to understand how to control its near surface elemental arrangement as well as how it behaves under the complex reaction environments. In this dissertation, the structural and elemental rearrangements of various bimetallic nanocatlyst were studied focusing on the processing and identifying the structure of a working catalyst. The first part emphasizes on how post-synthesis thermal process of bimetallic nanocatlyst for improved catalytic performance, which includes the thermally driven composition redistribution of Pt-Ni octahedral oxygen reduction reaction (ORR) nanocatalyst, the formation of Ag-Pt compositional intermetallics from alloy nanoparticles for formic acid oxidation (FAOR), and the regioselective atomic rearrangement of Ag-Pt octahedral catalysts by chemical vapor-assisted treatment. The second part is dedicated to identifying the actual structures of the bimetallic nanocatalysts under reaction conditions and how it affects performance, with more emphasis on product selectivity. The two model systems are metal-on-metal Rh-on-Pd for CO2 hydrogenation and [email protected] nanocatalyst for propylene epoxidation. Environmental transmission electron microscopy was utilized in most of the projects mentioned above and provided critical information with high spatial resolution in realtime. The in situ microscopic observations shows good correlation with ex situ microscoscopic, surface sensitive spectroscopic, electrochemical, and chromotagraphic analysis as well as density functional theory (DFT) calculations. The discovery in this dissertation indicates how the multiple governing factors determines the restructuring of different bimetallic nanocatalyst under various reactive thermal-chemical environments. It provides insights not just in the synthesis and processing of bimetallic nanocatalysts but also on the design of reaction conditions for the optimum working structure that leads to the best performance. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G%22%29&pagesize-30">Seebauer, Edmund G (committee member), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W%22%29&pagesize-30">Flaherty, David W (committee member), Champaign%22%20%2Bcontributor%3A%28%22Zuo%2C%20Jian-Min%22%29&pagesize-30">Zuo, Jian-Min (committee member).
Subjects/Keywords: Bimetallic nanocatalyst; Environmental transmission electron microscopy (ETEM); Core-shell nanoparticle; Adsorbate induced restructuring; Intermetallic; Heterogeneous catalysis
Pan, Y. (2017). Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/97539
Pan, Yung-Tin. "Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/97539.
Pan, Yung-Tin. "Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance." 2017. Web. 22 Jan 2020.
Pan Y. Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/97539.
Pan Y. Elemental and structural behaviors of bimetallic nanoparticles under reactive environments and its implication in catalyst design, processing, and performance. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/97539
5. Tsao, Kai-Chieh. Continuous production of supported and shaped metal nanocatalysts using conveyor transport system.
► One of the major challenges in nanotechnology is to generate nanoparticles with controlled size, shape and composition and at the same time meet the commercial… (more)
▼ One of the major challenges in nanotechnology is to generate nanoparticles with controlled size, shape and composition and at the same time meet the commercial standards of mass manufacturing. The conventional colloidal synthetic approach, though has the ability to produce well-defined nanocrystals, often needs careful tuning of the reaction parameters to result in site-selective monomer attachment. Unfortunately, these methods cannot be easily scaled up by simply increasing the reaction volume, which inevitably bring about undesired perturbation in the system and thus cause nonuniformity in final products. In this dissertation, conveyor transport system was developed as a new technique to produce continuously a family of supported and shaped metal nanocatalysts in a single-step process. With carbon monoxide (CO) as a major species to mediate the surface structures of metals, highly uniform cubic Pt/C with narrow size distribution could be synthesized in a continuous fashion; shaped carbon-supported Pt-M (M=Ni, Co, Fe) alloys were also generated using the same technique, demonstrating the capability of this system for generating bimetallic or potentially ternary alloys with controlled size and shape. This system was further applied to core-shell nanoparticles, and the morphology and composition of the cores as well as the shell thickness could be finely tailored to further enhance the activity and stabiltiy of the as-made electrocatalysts towards oxygen reduction reaction. In the near future, we will focus on the continuous production of different structured noble/non-noble metal nanomaterials as well as the coupling of this system to annealing process and/or MEA manufacturing stage, moving towards production of the industrial application of these classes catalysts. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G.%22%29&pagesize-30">Seebauer, Edmund G. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Guironnet%2C%20Damien%20S.%22%29&pagesize-30">Guironnet, Damien S. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Zhang%2C%20Yuanhui%22%29&pagesize-30">Zhang, Yuanhui (committee member).
Subjects/Keywords: Conveyor transport system; Carbon monoxide (CO); Shape; Lignad; Nanoparticle; Nanocatalyst; Transition metal; Alloy; Core-shell; Platinum (Pt); Palladium (Pd); Electrocatalysis; Heterogeneous catalysis; Fuel cell; Methanol oxidation reaction (MOR); Oxygen reduction reaction (ORR)
Tsao, K. (2017). Continuous production of supported and shaped metal nanocatalysts using conveyor transport system . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/98260
Tsao, Kai-Chieh. "Continuous production of supported and shaped metal nanocatalysts using conveyor transport system." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/98260.
Tsao, Kai-Chieh. "Continuous production of supported and shaped metal nanocatalysts using conveyor transport system." 2017. Web. 22 Jan 2020.
Tsao K. Continuous production of supported and shaped metal nanocatalysts using conveyor transport system. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/98260.
Tsao K. Continuous production of supported and shaped metal nanocatalysts using conveyor transport system. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/98260
6. Smith, Cartney E. Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects.
► Defective, leaky vasculature is characteristic of a wide variety of diseases, including arthritis, cancer, and cardiovascular disease. The ability to locally highlight vascular defects via… (more)
▼ Defective, leaky vasculature is characteristic of a wide variety of diseases, including arthritis, cancer, and cardiovascular disease. The ability to locally highlight vascular defects via medical imaging may therefore provide a way to improve diagnosis and treatment of some of the most significant diseases worldwide. As magnetic resonance imaging (MRI) provides the highest spatial resolution and best soft tissue contrast among common imaging techniques, it remains an appealing approach to vascular imaging. MRI, however, has relatively low sensitivity to its contrast agents compared to other clinical modalities, which limits its use in targeted applications. To address this issue, this thesis investigates the use of polymer materials to control the size, morphology, spatial organization, and surface properties of MR imaging probes to improve their relaxivity and accumulation at sites of interest. The first part of this thesis focuses on the design and development of gadolinium-based contrast agents. Chapter 2 describes the synthesis of a polymeric fastener to anchor gadolinium to the surface of a liposome through electrostatic and hydrophobic interactions. As a result, the probe provided greater contrast per dose than gadolinium chelates used clinically, and was able to beacon areas of vascular damage in in vivo models of ischemia. The strategy was then adapted to rapidly label stem cells for applications in cell tracking, as described in Chapter 3. Secondly, methods to improve the in vivo performance of superparamagnetic iron oxide nanoparticle (SPION) contrast agents are investigated. Chapter 4 explores the use of hyperbranched polyglycerol (HPG) in assembling SPIONs in the form of spherical clusters. By controlling the cluster size and molecular architecture of the polymer coating, optimal relaxivity of the SPIONs was achieved for sensitive imaging. In Chapter 5, the SPION clusters are further improved with the incorporation of targeting ligands and by inducing a wormlike morphology. This allowed for greater accumulation in areas of defective vasculature. Overall, this work contributes to a better understanding of contrast agent design and may serve to expedite efforts to improve the diagnosis and treatment of vascular diseases. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kong%2C%20Hyun%20Joon%22%29&pagesize-30">Kong, Hyun Joon (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kong%2C%20Hyun%20Joon%22%29&pagesize-30">Kong, Hyun Joon (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Kraft%2C%20Mary%20L.%22%29&pagesize-30">Kraft, Mary L. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Zimmerman%2C%20Steven%20C.%22%29&pagesize-30">Zimmerman, Steven C. (committee member).
Subjects/Keywords: Magnetic Resonance Imaging; Contrast Agent; Gadolinium; Iron Oxide; Polymer; Relaxivity; Targeted Delivery
Smith, C. E. (2015). Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/78755
Smith, Cartney E. "Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/78755.
Smith, Cartney E. "Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects." 2015. Web. 22 Jan 2020.
Smith CE. Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/78755.
Smith CE. Polymer-mediated assembly of MRI contrast agents and their use in imaging of vascular defects. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/78755
7. Oberst, Justin L. Electrocatalysis: dioxygen reduction and carbon dioxide conversion.
Degree: PhD, Chemistry, 2015, University of Illinois – Urbana-Champaign
► Due to increasing greenhouse gas emissions and their link to global climate change, much attention has been given towards both reducing current, atmospheric greenhouse gas… (more)
▼ Due to increasing greenhouse gas emissions and their link to global climate change, much attention has been given towards both reducing current, atmospheric greenhouse gas emissions and developing clean, renewable energy sources. The first section of this thesis focuses on reducing greenhouse gas emissions. Primarily focusing on CO2, routes towards reducing atmospheric levels include capture, sequestration, and conversion. For CO2 conversion, Au electrocatalysts have demonstrated high CO2 reduction activity to CO which can then be further converted to various synfuels or commodity chemicals. In the first section of this thesis, Au electrocatalysts are further probed by utilizing a Ag-based model using N-containing additives, such as pyrazole and benzotriazole, and surface-enhanced Raman spectroscopy (SERS). SERS reveals that only in the presence of N-containing additives a stronger CO band is seen. These additives do not affect the CO2 reduction mechanism of Au, as found by Tafel and product distribution analyses. The enhancement of the CO2 reduction rate on Au is also demonstrated by utilizing a known CO2 scavenger, ethanolamine, adsorbed on the Au surface. This result suggests that improving CO2 reduction should focus on the reactant side of the Sabatier plot. The next two sections of this thesis focus on the development of electrocatalysts for the oxygen reduction reaction (ORR), utilized in fuel cell applications. Due to the slow kinetics of the ORR, research has focused on studying how ORR catalysts reduce O2 and developing new cost-effective catalysts with improved activity. The second section of this thesis focuses on studying pyrolyzed Fe/N/C electrocatalysts, which have been shown to have high ORR activity similar to that of Pt, the benchmark catalyst. However, the active site of pyrolyzed Fe/N/C electrocatalysts for the ORR has been a source of debate since the initial discovery that these materials demonstrated activity towards the ORR. This has extremely limited systematic improvements to trial-and-error-based methods. In this section, a carbon-supported iron(II) phthalocyanine (FePc) that has been pyrolyzed at 800°C is utilized as a model catalyst. Studying the ORR on this material in the absence and presence of azide in acidic, neutral, and alkaline environments, the ORR activity and mechanism on pyrolyzed Fe/N/C materials can be further interrogated. The presence of azide served to enhance the ORR activity of this material in neutral electrolyte while having no effect in acidic or alkaline electrolytes. Tafel slope differences in addition to the azide enhancement suggest an Fe-centered active site for the ORR in pyrolyzed FePc and potentially other Fe/N/C electrocatalysts. This study provides both the first small molecule enhancement of the ORR with Fe/N/C catalysts and an additional route to further interrogate other electrocatalysts. The last section of this thesis centers on the adsorption of O2 on dynamic electrode surfaces, most specifically Pd, Pt, and Pt-alloys, during the… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Gewirth%2C%20Andrew%20A%22%29&pagesize-30">Gewirth, Andrew A (advisor), Champaign%22%20%2Bcontributor%3A%28%22Gewirth%2C%20Andrew%20A%22%29&pagesize-30">Gewirth, Andrew A (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Murphy%2C%20Catherine%20J.%22%29&pagesize-30">Murphy, Catherine J. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member).
Subjects/Keywords: Electrocatalysis; oxygen reduction; carbon dioxide reduction; spectroscopy; electrochemistry; surface stress
Oberst, J. L. (2015). Electrocatalysis: dioxygen reduction and carbon dioxide conversion . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/89269
Oberst, Justin L. "Electrocatalysis: dioxygen reduction and carbon dioxide conversion." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/89269.
Oberst, Justin L. "Electrocatalysis: dioxygen reduction and carbon dioxide conversion." 2015. Web. 22 Jan 2020.
Oberst JL. Electrocatalysis: dioxygen reduction and carbon dioxide conversion. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/89269.
Oberst JL. Electrocatalysis: dioxygen reduction and carbon dioxide conversion. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/89269
8. Shum, Wing. Effect of uptake pathway on non-viral gene delivery in vitro and in vivo.
► Efficient non-viral gene delivery often involves the conjugation of a cell-specific ligand to the vector, which directs the vector to its intended target through binding… (more)
▼ Efficient non-viral gene delivery often involves the conjugation of a cell-specific ligand to the vector, which directs the vector to its intended target through binding to a cellular receptor followed by internalization via endocytosis. However, little is known in terms of how the various endocytosis pathways affect the performance of the delivery vehicle. Previously, the Pack lab has demonstrated that caveolin-mediated endocytosis is important to in vitro polyethylenimine (PEI)- and polyamidoamine (PAMAM)-mediated gene delivery in HeLa cells through the use of small molecule drugs and small-interfering RNA [1-2]. The goal of this thesis is to further elucidate the effects of cellular uptake mechanism on non-viral gene delivery in vitro and in vivo utilizing a small hairpin RNA (shRNA) Tet-on system. Specifically, we have investigated the effects of clathrin-dependent endocytosis and caveolin-dependent endocytosis on the efficacy of PEI and PEI-derivative gene delivery in HeLa and MDA-MB-231 cell cultures and xenograft tumors. First, we attached transferrin and folate ligands to PEI to direct internalization by clathrin- and caveolin-mediated mechanisms, respectively, and transfected HeLa and MDA-MB-231 cells with targeted and untargeted PEI in the presence of small molecule drugs that inhibit clathrin- or caveolin-mediated endocytosis. We demonstrated through these studies that caveolin-dependent endocytosis is important to successful PEI-mediated gene delivery in both HeLa and, for the first time, MDA-MB-231 cells. In addition, a similar endocytic pathway study was performed using biodegradable PEI and acetylated PEI, which have demonstrated superior gene delivery capability compared to unmodified PEI in previous work [3-4]. The data show that regardless of structure, size, molecular weight, or zeta potential of the PEI-derivative polyplexes, caveolin-dependent endocytosis was critical to effective gene delivery. In order to further understand the impact of endocytic pathways on gene delivery efficiency in vitro, we modified HeLa and MDA-MB-231 cells to express small hairpin RNA (shRNA) that inhibit expression of clathrin, caveolin, or lamin A/C (negative control) protein expression (HeLa-CLTC, HeLa-CAV, HeLa-LAM, 231-CLTC, 231-CAV, and 231-LAM) in the presence of tetracycline. Using the shRNA Tet-on system, we demonstrated ~90% clathrin knockdown and ~60% caveolin knockdown in both modified HeLa and MDA-MB-231 cells. Subsequently, utilizing this inducible shRNA protein knockdown system, we transfected modified shRNA cells using both targeted and untargeted PEIs and confirmed that caveolin-dependent endocytosis is more important than clathrin-dependent endocytosis to PEI-mediated gene delivery, which corroborates the results observed in unmodified cell lines using small-molecule endocytosis inhibitors. Lastly, we investigated the effect of clathrin-dependent and caveolin-dependent endocytosis on in vivo PEI-mediated gene delivery in a xenograft murine tumor model. By inoculating modified shRNA cells… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Pack%2C%20Daniel%20W.%22%29&pagesize-30">Pack, Daniel W. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Pack%2C%20Daniel%20W.%22%29&pagesize-30">Pack, Daniel W. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Kraft%2C%20Mary%20L.%22%29&pagesize-30">Kraft, Mary L. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Roy%2C%20Edward%20J.%22%29&pagesize-30">Roy, Edward J. (committee member).
Subjects/Keywords: Gene delivery; Non-viral; Polyethylenimine (PEI); endocytosis; xenograft tumor; in vivo gene delivery; clathrin; caveolin; transferrin; folate; receptor-mediated endocytosis
Shum, W. (2013). Effect of uptake pathway on non-viral gene delivery in vitro and in vivo . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/45665
Shum, Wing. "Effect of uptake pathway on non-viral gene delivery in vitro and in vivo." 2013. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/45665.
Shum, Wing. "Effect of uptake pathway on non-viral gene delivery in vitro and in vivo." 2013. Web. 22 Jan 2020.
Shum W. Effect of uptake pathway on non-viral gene delivery in vitro and in vivo. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2013. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/45665.
Shum W. Effect of uptake pathway on non-viral gene delivery in vitro and in vivo. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/45665
9. Sayyah, Maryam. Calcium oxide-based sorbents for CO2 capture at high temperature.
► Carbon capture and storage (CCS) has been recognized as a promising approach to mitigate the rapidly increasing amount of CO2 in the atmosphere. The key… (more)
▼ Carbon capture and storage (CCS) has been recognized as a promising approach to mitigate the rapidly increasing amount of CO2 in the atmosphere. The key factor for the advancement of this technology lies in improved and cost-effective capture processes/materials. Pre-combustion CO2 capture from coal-fired power plants is of particular interest in integrated gasification combined cycle (IGCC) design. High concentrations of CO2 and elevated operating pressures/temperatures reduce the energy requirements of this process to 10-16%, which is roughly half that for post-combustion CO2 capture.[1] CaO has emerged as an attractive material to integrate in high temperature CO2 capture processes because of its favorable properties. However, the main drawback of CaO, namely sintering during calcination and thus dramatic decrease in surface area, has questioned its applicability on an industrial scale. To tackle the stability issue of CaO, different strategies have been examined from which incorporation of inert additives into CaO matrix shows great promise. High melting point refractory metal oxides have been identified as an example class of efficient additives. In this dissertation, two less common synthetic approaches, mechanochemistry and ultrasonic spray pyrolysis (USP), were utilized to prepare highly stable CaOcontaining sorbents for CO2 capture. The mechanochemical approach is as an example of top-down synthesis of materials, while spray pyrolysis is considered a bottom-up approach. First, a systematic study on the use of mechanochemistry (e.g., mechanical milling) for preparing CaO-based sorbents is reported. Important parameters such as milling intensity in high energy ball milling equipment, use of process control agent (i.e., wet or dry processing) and milling time were examined, and their effects on the performance and stability of treated CaO sorbents were studied. Next, the first use of ultrasonic spray pyrolysis as a continuous flow method for the facile synthesis of CaO-based materials is discussed. An extensive study of materials' characterization and CO2 capture performance has been conducted to examine the efficacy of prepared sorbents. Moreover, importance of bottom-up synthetic approach in retaining CO2 capacity is discussed. This work concludes with modeling the sorbent's performance via a classical shrinking core model to obtain quantitative values of useful parameters for equipment design (e.g., reaction rate constant and diffusivity decay). [1] Eide, L., I.; Bailey, D., W., Capture précombustion. Oil & Gas Science and Technology - Rev. IFP 2005, 60 (3), 475-484 Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Suslick%2C%20Kenneth%20S.%22%29&pagesize-30">Suslick, Kenneth S. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Suslick%2C%20Kenneth%20S.%22%29&pagesize-30">Suslick, Kenneth S. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W.%22%29&pagesize-30">Flaherty, David W. (committee member).
Subjects/Keywords: Calcium Oxide; CO2 capture; Mechanochemistry; Ultrasonic Spray Pyrolysis; Ball Milling; Electrostatic Precipitator; Pre-Combustion; Shrinking Core Model
Sayyah, M. (2014). Calcium oxide-based sorbents for CO2 capture at high temperature . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/46797
Sayyah, Maryam. "Calcium oxide-based sorbents for CO2 capture at high temperature." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/46797.
Sayyah, Maryam. "Calcium oxide-based sorbents for CO2 capture at high temperature." 2014. Web. 22 Jan 2020.
Sayyah M. Calcium oxide-based sorbents for CO2 capture at high temperature. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/46797.
Sayyah M. Calcium oxide-based sorbents for CO2 capture at high temperature. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/46797
10. Behl, Mayank. Desulfurization by reactive adsorption on oxide/metal composites.
► Nanostructured oxides – undoped, doped, composites and nano-heterostructures – having different morphologies and compositions were synthesized, characterized and tested under realistic operating conditions for their… (more)
▼ Nanostructured oxides – undoped, doped, composites and nano-heterostructures – having different morphologies and compositions were synthesized, characterized and tested under realistic operating conditions for their role as potential reactive adsorbents and catalysts in different environmental related applications. More specifically, different zinc oxide based nanostructures were studied for high and low temperature desulfurization applications. In addition, the focus was on moving away from the traditional practice of using oxides only as support materials. Oxides have traditionally been assigned the role of support materials in applications involving catalysis. As support materials, they are either considered as inert or they do occasionally participate indirectly along with more active "dispersed" metals by "strong metal-substrate interaction". This thesis presents results from a set of experiments with nanostructured oxide where reactive nature of the bulk oxide core is essential to the overall reaction. Most of the experimental schemes that constitute this thesis go beyond the role of oxides in surface reactivity to cases where bulk solid state reactivity is important. In experiments studying reactive desulfurization, different synthetic techniques were used to extend zinc oxide's temperature range by combining structural and compositional modifications. To increase sulfur capacity and uptake rate of ZnO-based sorbents at low/high temperatures, it is necessary to achieve a rapid surface reaction and complete bulk sulfidation of the oxide. To attain this goal, surface activity and diffusion through the ZnS product layer, must be accelerated. Nano-structuring of oxides, controlling the size and morphology together with the thoughtful compositional changes can help attain the goal. But bulk of the research has concentrated only on improving surface reactivity. In chapter 3, where developing reactive ZnO based adsorbents for high temperature syngas-desulfurization is one of the goals, it was experimentally demonstrated that a branched nanofibrous architecture combined with mixed metal oxide based composition (Zn-Ti-O) offers significantly enhanced sorbent bulk reactivity and recyclability, without needing to cycle temperature. Zn-Ti-O based nanofibrous mats offer rapid reaction rates and efficient material utilization of the oxide core by overcoming rate limiting transport resistance, which often affects conventional pellet-based sorbents. Problems of higher energy use, sluggish reactions, incomplete regeneration and progressive decline in activity are successfully mitigated. Higher reactivity enables regeneration to be carried out at a temperature that is identical to the sulfidation step, preventing damage and extra energy use caused by alternating temperatures. The efficient regeneration of the adsorbent is also aided by structural features such as the growth of hierarchical nanostructures (secondary nanorods) and preferential stabilization of a wurtzite phase in the sulfidation product. Such unique features are… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Jain%2C%20Prashant%20K.%22%29&pagesize-30">Jain, Prashant K. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Jain%2C%20Prashant%20K.%22%29&pagesize-30">Jain, Prashant K. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Schroeder%2C%20Charles%20M.%22%29&pagesize-30">Schroeder, Charles M. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G.%22%29&pagesize-30">Seebauer, Edmund G. (committee member).
Subjects/Keywords: Metal oxides; Materials chemistry; Nanostructures; Desulfurization; Nanocomposites; Solid-state reaction; Catalysis; Strong Metal-Metal Oxide Interaction; Organo-sulfur degradation; Brønsted acidity; Sour gas; High temperature desulfurization; electrospinning; incipient wet impregnation
Behl, M. (2014). Desulfurization by reactive adsorption on oxide/metal composites . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/49649
Behl, Mayank. "Desulfurization by reactive adsorption on oxide/metal composites." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/49649.
Behl, Mayank. "Desulfurization by reactive adsorption on oxide/metal composites." 2014. Web. 22 Jan 2020.
Behl M. Desulfurization by reactive adsorption on oxide/metal composites. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/49649.
Behl M. Desulfurization by reactive adsorption on oxide/metal composites. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/49649
11. Jensen, Cody. Photoactivity of titanium dioxide films with controlled orientation.
► Photocatalysis is being explored as a possible alternative to current disinfection treatment methods. Switching to photocatalysis could remove issues with disinfection byproducts and lower the… (more)
▼ Photocatalysis is being explored as a possible alternative to current disinfection treatment methods. Switching to photocatalysis could remove issues with disinfection byproducts and lower the operating costs. However, the activity of photocatalysts is too low to be used commercially. The most common photocatalyst is titanium dioxide, and while the activity of titanium dioxide is high when compared to other photocatalysts, improvements need to be made before commercialization. Increasing the activity of TiO2 can be done in a variety of methods, but this dissertation will focus only on a single method. Previous research has found that TiO2 has a range of activities based on the different phases and orientations. Many groups are focusing on growing crystals that are mainly covered with the most active facet. However, photocatalysis is about balancing reactions, and combining the most active oxidation site with poor reduction site will lower the activity. It is believe that by combining a site that is good for oxidation with a site that is good for reduction can outperform a catalyst with random orientations or even those with the expression of a single orientation. Controlling the phase and orientation of the titanium dioxide will be done by depositing TiO2 onto patterned substrates. The patterns were created through block copolymer lithography, providing sub-50 nm features over the surface of the substrate. The pattern will then be expressed through the film, creating a film that has controlled texture based upon the size scale of the patterned surface. These films will then be characterized by measuring the photoactivity through methylene blue degradation experiments. In addition to the textured films, an experiment was carried out in effort to help identify and quantify reactivity of different orientations of TiO2. This was done by photodepositing metal ions onto different TiO2 films and measuring the metal deposition over time. These experiments showed the range in activities for oxidation and reduction reactions for the phases and orientations tested. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Cahill%2C%20David%20G.%22%29&pagesize-30">Cahill, David G. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Cahill%2C%20David%20G.%22%29&pagesize-30">Cahill, David G. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G.%22%29&pagesize-30">Seebauer, Edmund G. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W.%22%29&pagesize-30">Flaherty, David W. (committee member).
Subjects/Keywords: titanium dioxide; TiO2; photocatalysis; photodegradation; thin film; sputter deposition; self-assembly
Jensen, C. (2014). Photoactivity of titanium dioxide films with controlled orientation . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/49705
Jensen, Cody. "Photoactivity of titanium dioxide films with controlled orientation." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/49705.
Jensen, Cody. "Photoactivity of titanium dioxide films with controlled orientation." 2014. Web. 22 Jan 2020.
Jensen C. Photoactivity of titanium dioxide films with controlled orientation. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/49705.
Jensen C. Photoactivity of titanium dioxide films with controlled orientation. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/49705
12. Oruc, Muhammed. Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes.
► Hydrogen is an environmentally sustainable energy carrier that can be stored. It is not found naturally and therefore must be artificially produced. We can obtain… (more)
▼ Hydrogen is an environmentally sustainable energy carrier that can be stored. It is not found naturally and therefore must be artificially produced. We can obtain hydrogen from renewable energy, such solar and wind energy, which is environmentally clean. One such a promising options is via electrolysis using electricity from a photovoltaic generator. In the first part of the dissertation we studied a microfluidic energy conversion device to produce hydrogen. Particularly, we proposed a new integrated system – a so-called "photovoltaic thermal water electrolyzer (PVTE)" – which consists of PV cells positioned on top of a planar micro-water electrolyzers in order to harness waste heat as a storable form of energy. The concept of PVTE has the outputs such as electricity and thermal storage, and also it provides hydrogen production efficiently. First, we provided a comprehensive analysis of the overall efficiency of the PVTE system. COMSOL Multiphysics software was used to predict the temperatures for the electrolyte and the PV cells operating at various temperatures and solar fluxes. Moreover, hourly and monthly efficiency analyses were accomplished for Phoenix, AZ in the year 2010. This new integrated approach is advantageous over conventional PV modules (Chapter 2). Second, we fabricated a micro-water electrolyzer which utilizes heat from PV cell and works as a heat sink in order to eliminate additional energy input for electrolysis in order to operate at elevated temperatures. We also presented electrode preparation and fabrication of the electrolyzer. The increase in the hydrogen production rate affirms the predictions of our system that utilizes waste heat from PV (Chapter 3). Finally, we successfully fabricated a new water electrolyzer including hydrophobic porous membrane. This new design allows us to manage gas production and collection in the chamber. By using this method, we are able to collect gases on the top of the electrolyzer at low flow rates at elevated temperatures (Chapter 4). Nanoporous membranes have received great attention in the fields of water desalination, biosensing, and chemical separations. Bare nanopores can be used as size-selective filters but if the surface chemistry of a nanopore is modified by coating it with another substance, however, enhanced separations based other properties can be achieved. Many studies have been performed on ion permselectivity across gold-coated charged surfaces and charged nanopores. In the second part of the dissertation, a focus of interfacial transport phenomena is proposed in order to achieve improved- charge selective nanofluidic systems. There have been numerous studies on the quality of organic SAMs as a blocking mechanism for prevention of ion adsorption. First, we investigated the electrochemical interfacial properties of a well-ordered SAM of 1-undecanethiol (UDT) on evaporated gold surface by EIS in electrolytes without a redox couple. Using a constant phase element (CPE) series resistance model, prolonged incubation times (up to 120 h) show… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Nuzzo%2C%20Ralph%20G.%22%29&pagesize-30">Nuzzo, Ralph G. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Nuzzo%2C%20Ralph%20G.%22%29&pagesize-30">Nuzzo, Ralph G. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W.%22%29&pagesize-30">Flaherty, David W. (committee member).
Subjects/Keywords: Hydrogen production; Microfluidic photovoltaic thermal water electrolyzer; Nanoscale ion transport
Oruc, M. (2014). Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/49837
Oruc, Muhammed. "Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/49837.
Oruc, Muhammed. "Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes." 2014. Web. 22 Jan 2020.
Oruc M. Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/49837.
Oruc M. Energy analysis and fabrication of photovoltaic thermal water electrolyzer and ion transport through modified nanoporous membranes. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/49837
13. Jhong, Huei-Ru. Design and characterization of catalysts and electrodes for electrochemical energy conversion applications.
► The modern world faces immense challenges associated with meeting its energy needs, due to its current dependence on fossil fuels. At the same time, the… (more)
▼ The modern world faces immense challenges associated with meeting its energy needs, due to its current dependence on fossil fuels. At the same time, the world faces the threat of global climate change linked to CO2 emissions. Indeed, global energy consumption has risen significantly since the industrial revolution and is expected to double again in the next 50 years. This is accelerating the depletion of conventional fossil fuels and has led to a steady increase in atmospheric CO2 levels. Taken together, the dual challenges of finding alternative energy sources and curbing CO2 emissions are daunting. Multifaceted approaches are needed to produce, store, and utilize energy in more efficient and environmentally sustainable ways. This thesis researches two energy conversion technologies that show promise to help address both challenges: fuel cells for efficient electrical power generation, and electrolysis of carbon dioxide into value-added intermediates for chemical production. Fuel cell technologies are expected to play an important role in many alternative energy conversion strategies, particularly for automotive applications. Detailed investigation of the relationship between the physical structure and electrochemical activity of fuel cell electrodes is a critical, yet often poorly reported or proprietary step in the manufacturing of cheaper and more durable configurations. This thesis employs X-ray micro-computed tomography (MicroCT) to visualize the architecture and buried interfaces of fuel cell electrodes in a non-destructive fashion. By coupling MicroCT-based visualization with microfluidic-based electrochemical characterization, variation in catalyst layer morphology can be directly correlated to electrode performance. Depositing catalyst layers via a fully-automated air-brushing method led to a 56% improvement in fuel cell performance and a significant reduction in electrode-to-electrode variability. Electrochemical reduction of CO2 into value-added chemicals potentially offers an economically viable route to recycle CO2 towards reducing CO2 emissions and dependence on fossil fuels. However, the current performance levels of CO2 electrolyzers are insufficient for commercialization due to the lack iii of catalysts with adequate activity and selectivity. This thesis researches the effects of catalyst layer deposition methodology on electrode performance. Air-brushing catalyst layers for CO2 reduction led to a 3-fold increase in partial CO current density and enhanced product selectivity (94%) and a 10-fold decrease in catalyst loading as compared to previous reports. Furthermore, this thesis reports carbon nanotube-supported gold catalysts for CO2 reduction exhibiting both higher activity and higher Faradaic efficiency for CO production. The 160 mA/cm2 partial current density for CO production achieved for this supported gold catalyst is to date the highest performance reported under ambient conditions. Such high activity can be attributed to enhanced catalyst utilization, evidenced by the high… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Gewirth%2C%20Andrew%20A.%22%29&pagesize-30">Gewirth, Andrew A. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Dillon%2C%20Shen%20J.%22%29&pagesize-30">Dillon, Shen J. (committee member).
Subjects/Keywords: catalysts; electrodes; CO2 reduction; fuel cells; nanoparticles; electrolysis
Jhong, H. (2014). Design and characterization of catalysts and electrodes for electrochemical energy conversion applications . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/50591
Jhong, Huei-Ru. "Design and characterization of catalysts and electrodes for electrochemical energy conversion applications." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/50591.
Jhong, Huei-Ru. "Design and characterization of catalysts and electrodes for electrochemical energy conversion applications." 2014. Web. 22 Jan 2020.
Jhong H. Design and characterization of catalysts and electrodes for electrochemical energy conversion applications. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/50591.
Jhong H. Design and characterization of catalysts and electrodes for electrochemical energy conversion applications. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/50591
14. Ribero-Rodriguez, Daniel. Materials development for multicomponent systems with variable oxidation states.
Degree: PhD, Materials Science & Engr, 2017, University of Illinois – Urbana-Champaign
► In this work, the synthesis by the polymeric steric entrapment method of materials that belong to the M1MnOx and M1Ti2(PO3)4 (M1= Li, Na, K,) families… (more)
▼ In this work, the synthesis by the polymeric steric entrapment method of materials that belong to the M1MnOx and M1Ti2(PO3)4 (M1= Li, Na, K,) families was evaluated. Furthermore, the influence on the physico-chemical characteristics of the powders by processing variables such as the dissolution conditions, pH of the solution, mixing conditions, drying procedures, HNO3 addition, amount of polymer (cation:organic ratio), characteristics of the exothermic reaction (C/N ratio), calcination/crystallization atmosphere and temperature, were investigated. Additionally, the electrochemical performance of the LiMn2O4 (LMO4) composition was evaluated and compared against commercial LiMn2O4 powders. Moreover, for powders in the M1Ti2(PO3)4 (M1= Li, Na, K,) family, their thermal expansion behavior were studied by means of high resolution (synchrotron radiation) in-situ high temperature X-ray diffraction, Rietveld refinement and the coefficient of thermal expansion analysis suite (CTEAS) software developed at UIUC. Specifically, powders in the family M1MnOx (LiMn3+O2, LiMn23+/4+O4, Li2Mn4+O3) could be synthesized at low temperature (~300°C) in a single step by taking advantage of the highly exothermic reaction produce by the nitrate and organic decompositions. In order to fully take advantage of the exothermic reactions and control the oxidation state, the precursor solutions had to be dried at low temperature (~70°C - 80°C) to avoid early nitrate/organic decompositions and the micro and macro atmospheres in the process had to be controlled. The micro atmosphere was controlled by the cation:organic ratio which additionally controlled the steric entrapment and the exothermic reaction. Moreover, the macro atmosphere was controlled by the furnace atmosphere. It was found that LiMn3+O2 can be produced at 700°C in flowing forming gas and using cation:organic ratio 6 to 1, whereas LiMn23+/4+O4 and Li2Mn4+O3 were produced in air, calcined at 300°C, and using a cation:organic ratio of 4:1. When powders were synthesized at low temperature (300°C – 500°C) high surface areas (14.6 m2/g for LMO4 at 300°C) and porous secondary particles composed by nanocrystals were produced, while at higher temperature (600°C – 800°C) crystals grew (micron range) and showed necking. This suggested the onset of the sintering process and exhibited a reduction of specific surface area (6.4 m2/g for LMO4 at 700°C). On the other hand, LMO4 produced in this work, exhibited similar or even better electrochemical performance than did LMO4 commercial powders (99.8 mAh/g and 90.1 mAh/g at C/10 and C/5, respectively). In contrast, 93.3 mAh/g, 110 mAh/g 131.8 mAh/g were the specific capacities obtained at C/10 for LMO4 synthesized at 300°C, 500°C and 700°C, respectively. Likewise, the specific capacities obtained at C/5 for LMO4 produced at 300°C, 500°C and 700°C were 88.9 mAh/g, 107 mAh/g and 128.3 mAh/g, respectively. The compounds LiTi2(PO4)3 (LTP), Li1.3Al0.3Ti1.7(PO4)3 (LATP), NaTi2(PO4)3 (NTP) and KTi2(PO4)3 (KTP) were produced by the polymeric… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kriven%2C%20Waltraud%20%20M%22%29&pagesize-30">Kriven, Waltraud M (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kriven%2C%20Waltraud%20%20M%22%29&pagesize-30">Kriven, Waltraud M (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Dillon%2C%20Shen%22%29&pagesize-30">Dillon, Shen (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Shoemaker%2C%20Daniel%20P%22%29&pagesize-30">Shoemaker, Daniel P (committee member).
Subjects/Keywords: Low temperature synthesis; Polymeric steric entrapment method; LiMn2O4; LMO; LiMnO2; Li2MnO3; M1Ti2(PO3)4; LiTi2(PO4)3; LTP; Li1.3Al0.3Ti1.7(PO4)3; LATP; NaTi2(PO4)3; NTP; KTi2(PO4)3; KTP; Electrochemical caracterization; Nanocrystals; Negative thermal expansion; Lithium ion batteries; Near zero thermal expansion
Ribero-Rodriguez, D. (2017). Materials development for multicomponent systems with variable oxidation states . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/99269
Ribero-Rodriguez, Daniel. "Materials development for multicomponent systems with variable oxidation states." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/99269.
Ribero-Rodriguez, Daniel. "Materials development for multicomponent systems with variable oxidation states." 2017. Web. 22 Jan 2020.
Ribero-Rodriguez D. Materials development for multicomponent systems with variable oxidation states. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/99269.
Ribero-Rodriguez D. Materials development for multicomponent systems with variable oxidation states. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/99269
15. Chang, SiWei. Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium.
► Transition metal phosphide (TMP) catalysts are selective and active towards C-O bond rupture during hydrodeoxygenation (HDO) of oxygenates, making them potential candidates for bio-oil upgrading.… (more)
▼ Transition metal phosphide (TMP) catalysts are selective and active towards C-O bond rupture during hydrodeoxygenation (HDO) of oxygenates, making them potential candidates for bio-oil upgrading. However, the mechanism by which the C-X (X = O, C, H) bond ruptures and the corresponding intrinsic barriers (i.e., for C-H, C-C, and C-O bond rupture) between transition metals and TMP catalysts are not well understood. Here, we synthesized and characterized a phosphorus (P) modified Ru(0001) surface by annealing Ru(0001) in the presence of PH3 gas under ultra-high vacuum conditions to produce Px-Ru(0001) (x is the ratio of P atoms to Ru atoms). The P0.43-Ru(0001) surface has a √7 x √7 low energy electron diffraction pattern, which is structurally similar to the (111) facet of well-characterized bulk Ru2P. Temperature programmed desorption measurements of CO and NH3 showed that the addition of P atoms decrease the binding energy of CO by up to 30 kJ mol-1 and NH3 by 14 kJ mol-1 as compared to pristine Ru(0001). This suggests that P atoms decrease the extent of electron exchange between Ru surfaces and adsorbates. We examined the decomposition of C1-C4 carboxylic acid (e.g., formic acid (FA), acetic acid (AA), propionic acid (PA), and butyric acid (BA)) on pristine Ru(0001) and P0.4-Ru(0001) surfaces. Temperature programmed reaction (TPR) and reactive molecular beam scattering (RMBS) experiments were used to determine bond rupture barriers and selectivity of C-O bond rupture compared to C-H/C-C bond rupture. The TPR results showed that longer alkyl carbon chains can promote self-stabilizing lateral interactions between carboxylates via dispersive (van der Waals) interactions, which is evidenced by increases in intrinsic activation energy (Ea) (1-5 kJ mol-1) for R-COOH bond rupture. RMBS of FA demonstrated that apparent activation energies (Eapp) of dehydration and dehydrogenation are greater on P0.43-Ru(0001) by 27 kJ mol-1 and 33 kJ mol-1, respectively, compared to Ru at temperatures greater than 500 K. Additionally, FA decomposition over P0.43-Ru(0001) is more selective toward C-O bond rupture than C-H bond rupture. Moreover, the addition of P atoms to Ru(0001) increases Ea values for all bonds (i.e., C-O, C-H and C-C bonds) by 5-50 kJ mol-1, which suggests that P-atoms decrease Ru surface electron back donation toward all adsorbates and changes the product selectivity by increasing energy barriers for C-O bond rupture more than C-H/C-C bond rupture. Collectively, these data and interpretations led to a proposed a set of elementary steps for carboxylic acid decomposition over Px-Ru(0001) and Ru(0001) surfaces. The results may provide guidance for the design of more selective P-modified transition metal catalysts to surgically cleave C-O bonds and convert biomass derived intermediates into platform chemicals and fuels. TMP catalysts are also active for alkane dehydrogenation, which is especially useful given the recent discovery of large shale-gas reserves. Here, we studied the effect of P atom on light alkane… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W%22%29&pagesize-30">Flaherty, David W (advisor), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W%22%29&pagesize-30">Flaherty, David W (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%22%29&pagesize-30">Seebauer, Edmund (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Rodriguez-Lopez%2C%20Joaquin%22%29&pagesize-30">Rodriguez-Lopez, Joaquin (committee member).
Subjects/Keywords: Heterogeneous catalyst; Transition metal phosphide; Surface science; Bio-oil hydrodeoxygenation; Light alkane dehydrogenation; Carboxylic acid; Cyclohexene
Chang, S. (2017). Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/99325
Chang, SiWei. "Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/99325.
Chang, SiWei. "Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium." 2017. Web. 22 Jan 2020.
Chang S. Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/99325.
Chang S. Effects of phosphorus on bond rupture during hydrodeoxygenation and dehydrogenation reactions on ruthenium. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/99325
16. Mirshafiee, Vahid. Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations.
► Nanoparticles (NPs) functionalized with targeting ligands are expected to improve the yield of targeted drug delivery by recognizing target cells and selectively delivering the therapeutic… (more)
▼ Nanoparticles (NPs) functionalized with targeting ligands are expected to improve the yield of targeted drug delivery by recognizing target cells and selectively delivering the therapeutic drugs to these cells. However, functionalized-NPs often have low targeting efficiency when they are administered in vivo. One of the major causes of this unfavorable outcome is that proteins and other biomolecules adsorb onto the particles upon NPs' injection into the blood stream, and form a biological coating named "protein corona." Protein corona formation could remarkably affect NPs' blood circulation, their cellular uptake, and targeting efficiency. Because current methods, such as PEGylation, could not fully resolve this issue, we aimed to address this challenge by exploiting the protein corona itself instead for targeted NP delivery. Here, we used the well-established opsonin-mediated phagocytosis of NPs to investigate if it is feasible to form an opsonin-enriched corona that actively targets NPs to immune cells by pre-coating NPs with gamma-globulins to promote the adsorption of opsonins (i.e. immunoglobulins) onto the NPs. Our results showed that while the corona of the gamma-globulin pre-coated NPs became enriched with opsonins upon incubation with human plasma, this enrichment did not enhance NP uptake by the target immune cells. Evaluation of the accessibility of immunoglobulins in the opsonin-enriched protein corona indicated that these proteins were not able to interact with their target biomolecules due to the screening effect of the other plasma proteins in the corona. Therefore, it is essential to control the spatial location of targeting proteins in the corona in order to form a functional corona for targeted NP delivery. In this work to exploit the protein corona for targeted NP delivery, the NPs were incubated with human plasma in vitro to mimic protein corona formation in the blood stream. However, other biological mediums, such as human serum, could be used in vitro for protein corona formation. The effect of these solutions, human serum or human plasma, on the corona's composition and NP's interactions with biological systems had not been thoroughly investigated. To address this issue, we exposed NPs to human serum and human plasma solutions and assessed the differences in these two protein coronas, and whether they affected NP uptake by cells. Our study demonstrates that NPs exposed to human plasma have larger diameters, more bound proteins, and more opsonins (e.g. fibrinogen) in their coronas than serum-exposed NPs. The presence of more opsonins in the coronas of the plasma-exposed NPs resulted in higher macrophage uptake of these particles than NPs exposed to human serum. Because, these two biological solutions yield protein coronas with different compositions, and human plasma better mimics the protein composition in the blood stream, human plasma should be utilized for in vitro protein corona studies. A challenge in the area of regenerative medicine was also addressed. Artificial cell cultures… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kraft%2C%20Mary%20L.%22%29&pagesize-30">Kraft, Mary L. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kraft%2C%20Mary%20L.%22%29&pagesize-30">Kraft, Mary L. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Murphy%2C%20Catherine%20J.%22%29&pagesize-30">Murphy, Catherine J. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Kong%2C%20Hyunjoon%22%29&pagesize-30">Kong, Hyunjoon (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member).
Subjects/Keywords: Nanoparticles; Protein Corona; Hematopoietic Cells
Mirshafiee, V. (2016). Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/92890
Mirshafiee, Vahid. "Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations." 2016. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/92890.
Mirshafiee, Vahid. "Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations." 2016. Web. 22 Jan 2020.
Mirshafiee V. Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2016. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/92890.
Mirshafiee V. Exploring nanoparticles' interactions with blood proteins and visualizing the heterogeneity within hematopoietic cell populations. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/92890
17. Li, Ming. Surface-mediated mechanisms for defect engineering in zinc oxide.
► The technological usefulness of a solid often depends upon the types and concentrations of the defects it contains. In semiconducting metal oxides like zinc oxide,… (more)
▼ The technological usefulness of a solid often depends upon the types and concentrations of the defects it contains. In semiconducting metal oxides like zinc oxide, the concentration and diffusion of oxygen point defects, like interstitials and vacancies, play a central role in various physical phenomena, such as gas sensing, bipolar switching, photoluminescence and photocatalysis. Defect engineering in metal oxides aims at manipulating material properties through controlling the defects' type, concentration, charge, spatial distribution, and mobility. A specific challenge that inhibits performance improvement in metal oxide devices for microelectronics, photonics, and photocatalysis usages is that bulk oxygen vacancies (VO) are typically numerous and serve as carrier recombination centers or electron current scatterers. One solution suggested by our laboratory is to thermally inject highly mobile charged oxygen interstitials (Oi) through metal oxide surfaces from the gas phase to annihilate VO in the underlying bulk. Developing novel mechanisms to control such diffusion process would be crucial in tailoring material defect chemistry for real life applications. The present work demostrates two special surface-based control mechanisms for this purpose in the case of zinc oxide: near-surface electrostatics and the chemical state of surface active sites. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G%22%29&pagesize-30">Seebauer, Edmund G (advisor), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G%22%29&pagesize-30">Seebauer, Edmund G (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Flaherty%2C%20David%20W%22%29&pagesize-30">Flaherty, David W (committee member), Champaign%22%20%2Bcontributor%3A%28%22Ertekin%2C%20Elif%22%29&pagesize-30">Ertekin, Elif (committee member).
Subjects/Keywords: Defect engineering; Surface science; Metal oxides; Zinc oxide; Oxygen interstitial; Oxygen diffusion; Isotope gas-solid exchange
Li, M. (2016). Surface-mediated mechanisms for defect engineering in zinc oxide . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/95585
Li, Ming. "Surface-mediated mechanisms for defect engineering in zinc oxide." 2016. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/95585.
Li, Ming. "Surface-mediated mechanisms for defect engineering in zinc oxide." 2016. Web. 22 Jan 2020.
Li M. Surface-mediated mechanisms for defect engineering in zinc oxide. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2016. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/95585.
Li M. Surface-mediated mechanisms for defect engineering in zinc oxide. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/95585
18. Huang, Qilong. Electronic band engineering: Titanium dioxide particulate layers for photocatalysis.
URL: http://hdl.handle.net/2142/102387
► Titanium dioxide (TiO2) is a wide bandgap semiconductor with many application advantages for photocatalysis. However, in the porous films that typify applications, photogenerated charge carriers… (more)
▼ Titanium dioxide (TiO2) is a wide bandgap semiconductor with many application advantages for photocatalysis. However, in the porous films that typify applications, photogenerated charge carriers typically drive reactions inefficiently due to fast recombination. To mitigate this problem, this work employs electronic band engineering principles drawn from integrated circuit design. In particular, the electric field normal to the nominal surface is extended spatially to sweep a larger fraction of photoholes toward the nominal surface to react before they recombine. This work demonstrates that the donor concentration (Nd) and surface potential (Vs) both control the spatial extent of the field in a predictable way, and enhance the reaction rate independently and in combination. Although a version of this concept has been demonstrated previously for nonporous polycrystalline films, such photocatalysts have limited practical value due to the small surface area per unit mass. The present work demonstrates that the concept can be extended to porous particulate films, which have much higher specific surface areas and therefore offer a much broader range of possible applications. The particulate films were synthesized by sintering commercially available nanoparticles together to provide an electrically continuous porous structure. Nd and Vs were measured by electrochemical impedance spectroscopy(EIS) and X-ray photoelectron spectroscopy(XPS), respectively. Apparent reaction rate constants were assessed using photocatalytic test reaction of methylene blue oxidation, which has well-known pseudo first order kinetics. The effective fluid diffusion coefficient of reactant D_(MB-pore) was controlled by adding polyethylene glycol of varied mass fraction to demonstrate the effects of reactant transport in the pores. The width(w) of the space charge layer(SCL) within the film was manipulated through Nd and Vs. Ndwas manipulated through hydrogen annealing(0~20mtorr) enabled variation of Nd from 1.27×〖10〗17 〖cm〗^(-3) to 5.26×〖10〗19 〖cm〗^(-3). Vs was manipulated using a deuterium plasma from 0.31 eV to 0.62 eV. These techniques permitted experimental variation of w from 4.6nm~172.3nm. A physics-based model was developed to rationalize the results. The model adequately fits the rate data with only two adjustable parameters: the intrinsic rate constant and fluid diffusion coefficient in the pores. Based upon this success, the model predicts how further improvements can be done through variations of Vs, Nd, film thickness, liquid diffusion coefficient, and light intensity and wavelength. Electronic band engineering through w (controlled by Nd and Vs) should increase reaction rates by up to an order of magnitude over the rate that would be observed if only hole diffusion influences the rate. The optimal film thickness is approximately 2~2.5 times the value of w. Higher fluid diffusion coefficients benefit the rate constant and effectiveness factor, but only to a certain point. For example, gas phase photoreactions do… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20%20G.%22%29&pagesize-30">Seebauer, Edmund G. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20%20G.%22%29&pagesize-30">Seebauer, Edmund G. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Ertekin%2C%20Elif%22%29&pagesize-30">Ertekin, Elif (committee member).
Subjects/Keywords: Electronic Band Engineering; Titanium Dioxide
Huang, Q. (2018). Electronic band engineering: Titanium dioxide particulate layers for photocatalysis . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/102387
Huang, Qilong. "Electronic band engineering: Titanium dioxide particulate layers for photocatalysis." 2018. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/102387.
Huang, Qilong. "Electronic band engineering: Titanium dioxide particulate layers for photocatalysis." 2018. Web. 22 Jan 2020.
Huang Q. Electronic band engineering: Titanium dioxide particulate layers for photocatalysis. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2018. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/102387.
Huang Q. Electronic band engineering: Titanium dioxide particulate layers for photocatalysis. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2018. Available from: http://hdl.handle.net/2142/102387
19. Chen, Wan-Ting. Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel.
Degree: PhD, Agricultural & Biological Engr, 2017, University of Illinois – Urbana-Champaign
► The objective of this study is to develop viable technologies to upgrade biocrude oil converted from wet biowaste via hydrothermal liquefaction (HTL). Three types of… (more)
▼ The objective of this study is to develop viable technologies to upgrade biocrude oil converted from wet biowaste via hydrothermal liquefaction (HTL). Three types of feedstocks (algae, swine manure, and food processing waste) were converted into biocrude oil via HTL for upgradation processes, which includes pretreating feedstocks, separation, esterification and neutralization of biocrude oil. Previous studies have revealed that excessive ash content in mixed-culture algal biomass (AW) appeared to reduce the higher heating value (HHV) and hydrocarbon compositions in the biocrude oil. To resolve this issue, physical pretreatments on AW biomass were carried out to decrease the ash content and improve the biocrude oil quality. AW biomass with different ash content was converted into biocrude oil via HTL at 300°C for 1 h reaction time, which is the previously determined optimum condition for producing biocrude oil. As the ash content of AW biomass was decreased from 53.3 wt.% to 39.0-43.5 wt.% after screen pretreatments, the HHV of the biocrude oil was substantially improved from 27.5 MJ/kg to 32.3 MJ/kg and the amounts of the light oil (boiling point of 100-300°C) were increased from 31wt.% to 49 wt.%. In contrast, GC-MS analyses of pretreated algal biocrude oil and aqueous products demonstrate that the ash content promoted denitrogenation, catalyzed the formation of hydrocarbons, and mitigated the recalcitrant compounds in aqueous products under the HTL processes. In order to elucidate the role of the ash content under the HTL processes, model algae, Chlorella, with different amounts of representative ash content (egg shells in this study) were converted into biocrude oil at the same reaction condition (i.e., 300°C for 1 hr reaction time). Elemental and thermogravimetric analyses of the biocrude oil both show that when the ash content in the algal feedstock was below 40 wt.%, the HHV and boiling point distribution of the algal biocrude oil could be hardly changed. This result signifies the feasibility of using ash-rich biomass as an HTL feedstock and diminishes the necessity of multi-step pretreatments of ash-rich biomass for biofuel applications. This study also demonstrates a proof-of-concept in the production of high quality renewable biofuel from wet biowaste via hydrothermal liquefaction (HTL). Distillation was employed to effectively separate the biocrude converted from swine manure (SW), food processing waste (FPW), and Spirulina platensis (SP) via HTL into different fractions. Distillation curves of different types of HTL biocrude oil were reported. Physicochemical characterizations, including density, viscosity, elemental test, chemical compositions, and acidity, were conducted on distillates separated from different feedstocks. SW-, FPW-, and SP-derived biocrude respectively contains 15 wt.% , 56 wt.%, and 15 wt.% distillates with heating values of 43-46 MJ/kg and alkanes with carbon numbers ranging from C8 to C18. Compared to the distillates from SW- and SP-derived biocrude oil, the distillates from… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Zhang%2C%20Yuanhui%22%29&pagesize-30">Zhang, Yuanhui (advisor), Champaign%22%20%2Bcontributor%3A%28%22Zhang%2C%20Yuanhui%22%29&pagesize-30">Zhang, Yuanhui (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Lee%2C%20Chia-Fon%22%29&pagesize-30">Lee, Chia-Fon (committee member), Champaign%22%20%2Bcontributor%3A%28%22Sharma%2C%20B.K.%22%29&pagesize-30">Sharma, B.K. (committee member).
Subjects/Keywords: Hydrothermal liquefaction; Biofuel
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Chen, W. (2017). Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/97597
Chen, Wan-Ting. "Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/97597.
Chen, Wan-Ting. "Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel." 2017. Web. 22 Jan 2020.
Chen W. Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/97597.
Chen W. Upgrading hydrothermal liquefaction biocrude oil from wet biowaste into transportation fuel. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/97597
20. Kim, Hyo Na. Sonocrystallization and sonofragmentation.
► Acoustic cavitation occurs when ultrasound is applied to a liquid. Bubbles are generated, oscillate, expand and, when specific criteria are met, implosively collapse. These collapses… (more)
▼ Acoustic cavitation occurs when ultrasound is applied to a liquid. Bubbles are generated, oscillate, expand and, when specific criteria are met, implosively collapse. These collapses generate hot spots and shockwaves. Hot spots have intense local temperatures (~5,000 K) and pressures (~1,000 atm), and a rapid heating and cooling rate (> 1010 K s-1). Shockwaves can induce crystallization, i.e., sonocrystallization, or break existing crystals, i.e., sonofragmentation in solid-liquid mixtures. The sonofragmentation of ionic and molecular crystals is discussed in Chapters 2 and 3. When ultrasound was applied to slurries of ionic or molecular crystals, crystal breakage occurred not by interparticle collision but by direct interactions between crystals and shockwaves. Sonofragmentation rates depended strongly on the strength of the crystal material, as described by its Vickers hardness or Young's modulus. This is a mechanochemical extension of the Bell–Evans–Polanyi Principle or Hammond's Postulate: i.e., activation energies for solid fracture correlate with the binding energies of solids. In addition, from comparisons of sonofragmentation patterns between ionic and molecular crystals, it was confirmed that the sonofragmentation of ionic crystals was more sensitive to changes in material hardness than that of molecular crystals. Finally, two possible mechanisms of particle breakage via sonofragmentation were suggested: particle breakage from defects formed by shock-induced compression-expansion of the initial crystal and particle breakage from defects created during shock-induced bending or torsion of the initial crystal. In Chapters 4 and 5, the sonocrystallization of pharmaceutical agents having inherently low water solubility is discussed. Chapter 4 describes the development of a spray sonocrystallization system. Spray sonocrystallization produced nano-scale carboxyphenyl salicylate crystals (c.a. 100 nm) with a narrow size distribution. The crystal size was controllable by changing the initial solute concentration. In Chapter 5, carbamazepine crystals were produced via various crystallization methods, including spray sonocrystallization. Crystal sizes, solubility and dissolution rates were compared among carbamazepine crystals generated by five different crystallization methods. Spray sonocrystallization produced the smallest crystals and resulted in the most rapid observed dissolution rate in water. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Suslick%2C%20Kenneth%22%29&pagesize-30">Suslick, Kenneth (advisor), Champaign%22%20%2Bcontributor%3A%28%22Suslick%2C%20Kenneth%22%29&pagesize-30">Suslick, Kenneth (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Murphy%2C%20Catherine%22%29&pagesize-30">Murphy, Catherine (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Jain%2C%20Prashant%22%29&pagesize-30">Jain, Prashant (committee member).
Subjects/Keywords: Sonocrystallization; Sonofragmentation
Kim, H. N. (2017). Sonocrystallization and sonofragmentation . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/98211
Kim, Hyo Na. "Sonocrystallization and sonofragmentation." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/98211.
Kim, Hyo Na. "Sonocrystallization and sonofragmentation." 2017. Web. 22 Jan 2020.
Kim HN. Sonocrystallization and sonofragmentation. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/98211.
Kim HN. Sonocrystallization and sonofragmentation. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/98211
21. Wu, Kunna. Modeling of the electrochemical conversion of CO2 in microfluidic reactors.
► Today's world faces immense challenges associated with meeting its energy needs, due to its current dependence on fossil fuels. At the same time, the world… (more)
▼ Today's world faces immense challenges associated with meeting its energy needs, due to its current dependence on fossil fuels. At the same time, the world faces the threat of global climate change linked to CO2 emissions. Indeed, global energy consumption is expected to double in the next 50 years. This accelerates the depletion of conventional fossil fuels and leads to a steady increase in CO2 emission. Globally, CO2 emission through the combustion of fossil fuels has increased by about 1.6 times between 1990 (the Kyoto Protocol reference year) and 2013, with approximately 9.9 GtC added to the atmosphere in 2013. Taken together, the dual challenges of finding alternative energy sources and curbing CO2 emissions are very daunting. When it is powered by carbon-neutral electricity sources, the electrochemical conversion of CO2 into value-added chemicals offers an economically viable route to recycle CO2 towards reducing CO2 emissions and reducing dependence on fossil fuels. The majority of prior studies on the electrochemical conversion of CO2 are experimental in nature, focused on unravelling the mechanisms of known catalysts. As an alternative approach to the laborious experiments, first-principles modeling of the electrochemical reactors can complement the current experimental work by elucidating the complex transport and electrochemistry, particularly in the porous electrodes, and help in the design and optimization of such reactors. Currently, there is a lack of detailed modeling for the aqueous electrochemical reduction of CO2 in a microfluidic reactor, which has been demonstrated experimentally to be an effective reactor and a versatile analytical tool. This thesis focuses on developing a mathematical modeling framework for the electrochemical conversion of CO2 to CO in microfluidic reactors. Conversion of CO2 into CO is attractive due to the versatility of CO (with H2) as a feedstock for the production of a variety of products including liquid hydrocarbon fuels. A full model that takes into account of all the significant physics and electrochemistry in the cell, including the transport of species and charges, momentum and mass conservations, and electrochemical reactions, is first formulated. The full model that comprises of a system of coupled partial differential equations is solved using finite element method. It is then calibrated and validated using experimental data obtained for various inlet flow rates and compositions. Parametric studies for various design and operating variables are subsequently performed using the validated model. To reduce the computational time, yet preserve the geometric resolution and leading order behavior of the cell, narrow-gap approximation and scaling arguments are invoked which allow for significant reduction in the mathematical complexity of the full model and eventually approximate analytical solutions. The unit cell models are then extended to stack models for simulation and analysis of the electrochemical reduction of CO2 in a microfluidic cell stack. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Higdon%2C%20Jonathan%20J.L.%22%29&pagesize-30">Higdon, Jonathan J.L. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Birgersson%2C%20Karl%22%29&pagesize-30">Birgersson, Karl (committee member), Champaign%22%20%2Bcontributor%3A%28%22Jiang%2C%20Jianwen%22%29&pagesize-30">Jiang, Jianwen (committee member), Champaign%22%20%2Bcontributor%3A%28%22Karimi%2C%20Iftekhar%22%29&pagesize-30">Karimi, Iftekhar (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Khan%2C%20Saif%22%29&pagesize-30">Khan, Saif (committee member).
Subjects/Keywords: carbon dioxide; electrochemical conversion; microfluidic; modeling; syngas; cell stacks
Wu, K. (2015). Modeling of the electrochemical conversion of CO2 in microfluidic reactors . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/88054
Wu, Kunna. "Modeling of the electrochemical conversion of CO2 in microfluidic reactors." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/88054.
Wu, Kunna. "Modeling of the electrochemical conversion of CO2 in microfluidic reactors." 2015. Web. 22 Jan 2020.
Wu K. Modeling of the electrochemical conversion of CO2 in microfluidic reactors. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/88054.
Wu K. Modeling of the electrochemical conversion of CO2 in microfluidic reactors. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/88054
22. Denard, Carl. Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes.
► Catalytic asymmetric synthesis is founded on three pillars: organometallic catalysis, organoca-talysis and biocatalysis. Over the years, catalysts of these three classes have enabled ground-breaking chemical… (more)
▼ Catalytic asymmetric synthesis is founded on three pillars: organometallic catalysis, organoca-talysis and biocatalysis. Over the years, catalysts of these three classes have enabled ground-breaking chemical transformations. The application of chemocatalysis to the manufacturing of chemicals is widespread, and biocatalysis is increasingly being used industrially. To streamline chemical syntheses, there has been and continuous to be a push to develop one-pot reactions, within which several catalysts from the same or disciplines are combined to catalyze numerous chemical steps and yield enantiopure products in high yield and selectivity. While this strategy is widespread in the respective fields of chemocatalysis and biocatalysis, examples in which chemocatalysts are combined with biocatalysts in one-pot are few and far between, apart from the seminal works of Backväll and Kim in which metal racemization complexes combined with lipases catalyze dynamic kinetic resolutions. The work presented in this thesis vows to bridge the gap between chemical catalysts and en-zymes by engineering one-pot tandem reactions between these two catalytic systems, with a par-ticular interest on combining cytochrome P450s and enoate reductases with organometallic cata-lysts. On the one hand, considerable efforts in transition-metal catalysis have culminated in prac-tical and efficient transformations such as isomerization, olefin metathesis, carbene-mediated insertions and others. On the other hand, metalloenzymes and reductases have been investigated and engineered to catalyze reactions with organic compounds that are synthetically and industri-ally important. First, we combined an isomerization of alkenes catalyzed by a ruthenium tri-phenylphosphine complex with cytochrome P450s variants that catalyze the epoxidation of these alkenes. While the isomerization catalyst and P450 BM3 variants could operate efficiently in a biphasic system, mass transfer limitations coupled with low enzyme TTNs greatly limited reaction yields. With a more active P450 BM3, namely the wild type P450, a biphasic reaction combining a cross metathesis reaction catalyzed by a ruthenium catalyst with a regioselective enzymatic epoxidation. A 90% yield of a single epoxide could be obtained selectively from the cross metathesis of two alkenes, a reaction that would yield a maximum 64% yield if ran sequentially. The scope of this tandem reaction was later extended to aromatic substrates, through a combina-tion of enzyme, substrate and reaction engineering. Lastly, we discovered that an electron defi-cient iron porphyrin catalyzed diazo coupling reactions in high yields in buffer and at room tem-perature. Its substrate scope included not diazoacetates, but also diazoketones to form dienones. When this catalyst was combined with an enoate reductase which catalyzes the reduction of α, β-unsaturated alkenes, in one pot, no mutual deactivation of the two catalytic species was ob-served. Complete reduction of the activated alkenes formed was observed. To form chiral… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Zhao%2C%20Huimin%22%29&pagesize-30">Zhao, Huimin (advisor), Champaign%22%20%2Bcontributor%3A%28%22Hartwig%2C%20John%20F.%22%29&pagesize-30">Hartwig, John F. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Zhao%2C%20Huimin%22%29&pagesize-30">Zhao, Huimin (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Schuler%2C%20Mary%20A.%22%29&pagesize-30">Schuler, Mary A. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (committee member).
Subjects/Keywords: P450 BM3; tandem catalysis; enoate reductase; asymmetric synthesis; chemoenzymatic one-pot reaction; heme porphyrin; epoxidation; reduction; olefin metathesis
Denard, C. (2014). Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/49700
Denard, Carl. "Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/49700.
Denard, Carl. "Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes." 2014. Web. 22 Jan 2020.
Denard C. Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/49700.
Denard C. Engineering novel tandem reactions using organometallic catalysts and (metallo)enzymes. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/49700
23. Whittenberg, Joseph James. Micro- and millifluidic platforms for imaging agent synthesis.
► Molecular imaging, the non-invasive visualization of cellular and sub-cellular events, holds great promise to improve the basic understanding of biochemical processes and clinical diagnosis of… (more)
▼ Molecular imaging, the non-invasive visualization of cellular and sub-cellular events, holds great promise to improve the basic understanding of biochemical processes and clinical diagnosis of diseases. One widely used molecular imaging technique is positron emission tomography (PET) that is especially useful for clinical oncology applications. PET has seen remarkable growth recently due to improvements in the regulation of PET radiotracers and the development of multimodal imaging set-ups that combine the sensitivity of PET with X-ray computed tomography (CT) or magnetic resonance imaging (MRI) that provide anatomical details. To date the most widely used PET radiotracer is [18F]fluorodeoxyglucose ([18F]FDG). Despite the widespread use of [18F]FDG, 18F has a short half-life and [18F]FDG cannot detect certain cancers. There is a desire to develop radiometal-based radiotracers that have a wide selection of radioisotope half-lives from 10's of minutes to days. Additionally, these tracers have the potential for flexible synthesis of tumor-specific tracers by easily changing the biomolecule (BM) utilized. However, radiometal-based PET radiotracers still face key challenges including (1) site-specific attachment of bifunctional chelators (BFCs), responsible for chelating the radiometal, to tumor-targeting biomolecules and (2) improving synthesis equipment to reduce reagent use and radiation shielding costs. My dissertation primarily focuses on addressing the challenges associated with radiometal-based PET radiotracer synthesis. "Click chemistry", or more specifically Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), was utilized to address the concern regarding site-specific attachment of BFCs to BMs. CuAAC, like other "click reactions", yields products with few side reactions under mild reaction conditions which is key when working with biomolecules. However, PET radiotracers are typically made in small batches because radioisotopes are utilized. Microfluidic platforms enable handling of small volumes, reducing reagent use and simultaneously minimizing radiation shielding costs due to their inherently small size. Here I describe how microfluidics was merged with the "click chemistry" concept to produce BM-BFC conjugates with the potential to be used as PET radiotracers. In Chapter 2 I describe the initial development and fabrication of a "click chip" with immobilized Cu(I) catalyst to facilitate CuAAC reactions that also minimizes purification requirements because the cytotoxic Cu(I) catalyst is immobilized to the microfluidic platform. Chapter 3 discusses how the "click chip" was improved to reduce solvent loss and enable longer reactions to conjugate BMs and BFCs. Nanoparticles (NPs) are another class of imaging agents that have some advantages over small molecule-based imaging agents (e.g., facile incorporation of multiple imaging modalities). However, many NPs are synthesized using low-yield synthetic strategies not amenable for scale up (e.g., microfluidics). Microfluidic mixers have been well characterized over… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20JA%22%29&pagesize-30">Kenis, Paul JA (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20JA%22%29&pagesize-30">Kenis, Paul JA (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Reichert%2C%20David%20E%22%29&pagesize-30">Reichert, David E (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Meng%2C%20Ling-Jian%22%29&pagesize-30">Meng, Ling-Jian (committee member), Champaign%22%20%2Bcontributor%3A%28%22Guironnet%2C%20Damien%20S%22%29&pagesize-30">Guironnet, Damien S (committee member).
Subjects/Keywords: Microfluidics; Click chemistry; Cu(I)-catalyzed azide-alkyne cycloaddition; Radiotracers; Millifluidics; Mixing; Nanoparticles
Whittenberg, J. J. (2017). Micro- and millifluidic platforms for imaging agent synthesis . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/98332
Whittenberg, Joseph James. "Micro- and millifluidic platforms for imaging agent synthesis." 2017. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/98332.
Whittenberg, Joseph James. "Micro- and millifluidic platforms for imaging agent synthesis." 2017. Web. 22 Jan 2020.
Whittenberg JJ. Micro- and millifluidic platforms for imaging agent synthesis. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2017. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/98332.
Whittenberg JJ. Micro- and millifluidic platforms for imaging agent synthesis. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2017. Available from: http://hdl.handle.net/2142/98332
24. Lazebnik, Mihael. Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes.
► Small interfering RNA (siRNA), when delivered to cells, is able to elicit a potent post transcriptional gene silencing with enormous therapeutic potential. It has been… (more)
▼ Small interfering RNA (siRNA), when delivered to cells, is able to elicit a potent post transcriptional gene silencing with enormous therapeutic potential. It has been demonstrated that siRNA is able to tackle a wide range of conditions that include viral infections, cancer, immunological disorders, and even alcoholism. Still, siRNA is too large to passively internalize into the cells by means of diffusion, and its electric charge is of the same polarity as the net-anionic plasma membranes, making it exceedingly difficult to even approach the cells. As such, various materials have been developed to allow the delivery of the siRNA molecules to their primary sites of activity in cytosol. This, however, only solved the problem in part, since such vectors interact with oligonucleotides to form particles that, as commonly believed, require endocytosis to enter the cells. Endocytosis is a process by which cells communicate with their surroundings and internalize nutrients. The fundamental principle in this process is that the internalized material is secluded from the cytosol in vesicles formed by invaginations of sections of plasma membranes. These vesicles transport and sort material in a highly organized manner and most commonly either recycle the internalized material out of the cells or deliver it to be degraded in lysosomes. Once again, in order to enter cytosol, siRNA molecules must cross a biological membrane. Thousands of chemical formulations have been adapted or de novo synthesized to overcome the various barriers to siRNA delivery. These include targeting to specific cells, evasion from immune system, cell internalization, and escape from the endocytic vesicles into cytosol. Still, since endocytosis occurs inside of the cells and consists of steps that last time intervals of different orders of magnitude, it is has become a great challenge to design a vector material capable of mediating the delivery of siRNA into the cytosol. The research presented in this dissertation will illuminate the reasons behind the success of some of the most common delivery materials: polyethylenimine (PEI) and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP) liposomes with various amounts of cholesterol as "helper lipids." In order to gain new insights into the endocytosis of siRNA-based synthetic particles, I exploited the ability of horseradish peroxidase (HRP) to elicit crosslinking and subsequent isolation of different groups of vesicles within the endocytic system. This method allows for a quantitative description of the intracellular kinetics of internalized complexes, and was demonstrated to be superior to other commonly used methods. The data acquired by this method were used to construct a mathematical model describing endocytosis of the investigated vectors that revealed a series of interesting results; the success of PEI is based on the ability of the PEI-based particles to attach to plasma membranes. PEI-based particles internalize into early endosomes and gain access to cytosol primarily… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Pack%2C%20Daniel%20W%22%29&pagesize-30">Pack, Daniel W (advisor), Champaign%22%20%2Bcontributor%3A%28%22%28advisor%29%22%29&pagesize-30">(advisor), Champaign%22%20%2Bcontributor%3A%28%22Kong%2C%20Hyunjoon%22%29&pagesize-30">Kong, Hyunjoon (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Underhill%2C%20Gregory%20H%22%29&pagesize-30">Underhill, Gregory H (committee member).
Subjects/Keywords: endocytosis; siRNA delivery; Non-viral gene delivery; polyplexes; lipoplexes; polyethylenimine (PEI); N-[1-(2,3-iii dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP); cholesterol
Lazebnik, M. (2015). Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/88965
Lazebnik, Mihael. "Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/88965.
Lazebnik, Mihael. "Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes." 2015. Web. 22 Jan 2020.
Lazebnik M. Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/88965.
Lazebnik M. Quo vadis: quantitative evaluation of intracellular kinetics of siRNA delivered by poly-and-lipoplexes. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/88965
25. Gao, Wenpei. Imaging of nanoparticles and nanocrystal interactions with oxide surfaces.
Degree: PhD, Materials Science & Engineering, 2015, University of Illinois – Urbana-Champaign
► Surfaces and interfaces have a major impact on the structure and properties of materials, especially in nanostructures, including supported metal nanoparticles (NPs) used as catalysts… (more)
▼ Surfaces and interfaces have a major impact on the structure and properties of materials, especially in nanostructures, including supported metal nanoparticles (NPs) used as catalysts in chemical industries and environmental remediation. For example, oxide supported gold NPs demonstrate outstanding chemical activity in selective oxidation of CO at low temperatures, and strong support effect is believed to be involved in the enhancement of their catalytic activities. The interfaces formed by the Au NPs and their supports are heterogeneous. In homogeneous materials, another type of interfaces is formed at grain boundaries. Such interfaces play a critical role in materials' microstructure development. Recent advances in electron microscopy have significantly improved our capability for studying interfaces. Here we extend the interfacial study to two types of samples, one sample is Au NPs supported on rutile (TiO2) surface and the other is transformation of Pt icosahedral NPs. In both cases, information obtained by innovative electron microscopy reveals atomic interfacial interactions at unprecedented details. In our study on the Au/TiO2 catalyst, we systematically examined the interfacial effects on the structure of Au NCs and the interface using aberration corrected scanning transmission electron microscopy (AC-STEM). Results show that by high temperature annealing, Au NCs supported on stepped TiO2 (110) surfaces develop an approximate and preferred epitaxial relationship with Au(111)||TiO2(110). The interfacial interaction can modify the shape of the NCs, and introduce significant strain in Au NCs near the surface steps. This strain is seen relaxed in Au layers away from the interface. By measuring the shape parameters, an interfacial energy of γint ~ 0.48 J/m2 is calculated for Au NCs on TiO2 (110) surface steps. This value is smaller than that for Au NCs on flat TiO2 (110) surfaces, which explains the stability of the interface. To examine the heterogeneous interface in three-dimensions, we further developed the depth-sectioning technique using STEM. Using this, we obtained conclusive evidences of interfacial Au atoms formed on the rutile (TiO2) (110) surfaces by activation using high temperature (~500ºC) annealing in air. Results show that the interface between Au nanocrystals and TiO2 (110) surfaces consists of a single atomic layer with Au atoms embedded inside the Ti-O plane. The number of interfacial Au atoms is estimated from ~1 to 8 in an interfacial atomic column. Direct impact of interfacial Au atoms is observed on an enhanced Au-TiO2 interaction and the reduction of surface TiO2. To determine the TiO2 surface structure and interface oxidation state, we performed atomic resolution imaging of the Au/TiO2 (110) interface using both annular bright field (ABF) STEM and chromatic aberration (Cc) corrected TEM. Direct interpretable images of oxygen columns are achieved, together with gold and titanium atomic columns. We located the bridging oxygen atoms on the surface and at the interface, and observed… Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Zuo%2C%20Jian-Min%22%29&pagesize-30">Zuo, Jian-Min (advisor), Champaign%22%20%2Bcontributor%3A%28%22Zuo%2C%20Jian-Min%22%29&pagesize-30">Zuo, Jian-Min (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member), Champaign%22%20%2Bcontributor%3A%28%22Rockett%2C%20Angus%22%29&pagesize-30">Rockett, Angus (committee member), Champaign%22%20%2Bcontributor%3A%28%22Trinkle%2C%20Dallas%22%29&pagesize-30">Trinkle, Dallas (committee member).
Subjects/Keywords: Nanoparticle; electron microscopy
Gao, W. (2015). Imaging of nanoparticles and nanocrystal interactions with oxide surfaces . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/89035
Gao, Wenpei. "Imaging of nanoparticles and nanocrystal interactions with oxide surfaces." 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/89035.
Gao, Wenpei. "Imaging of nanoparticles and nanocrystal interactions with oxide surfaces." 2015. Web. 22 Jan 2020.
Gao W. Imaging of nanoparticles and nanocrystal interactions with oxide surfaces. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/89035.
Gao W. Imaging of nanoparticles and nanocrystal interactions with oxide surfaces. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/89035
26. Chua, Yong Ping Gavin. Improved catalysts with properties controlled by semiconductor band engineering.
► Difficulties in achieving control over carrier concentration have impeded progress toward tailoring the carrier concentration in semiconducting oxide supports for metal catalysts. Such tailoring could… (more)
▼ Difficulties in achieving control over carrier concentration have impeded progress toward tailoring the carrier concentration in semiconducting oxide supports for metal catalysts. Such tailoring could make possible the intentional exploitation of the Schwab effect, in which the carrier concentration in the semiconducting support affects reaction rate on the supported metal catalyst. An atomic layer deposition synthesis technique developed in the Seebauer lab allows variation of thin polycrystalline anatase TiO2 film thickness that provides an unconventional means of varying carrier concentration. The film thickness has an inverse relationship with its carrier concentration, as an increase in film thickness reduces the concentration of electrically active grain boundaries, locations where native donor defects aggregate. These TiO2 films were sputtered with small amounts of Pt and ran under a CO oxidation test reaction to demonstrate the electronic influence of the TiO2 support on Pt catalytic activity. Over a range of TiO2 film thickness corresponding to carrier concentrations that varied by a factor of around 10, the reaction rate coefficient kCO in excess CO increased by about 70% while the rate coefficient kO2 in excess O2 decreased by 30%. This can be rationalized by the extent of electron injection from the TiO2 support into Pt. Increased electron injection into Pt, due to increased TiO2 carrier concentration, decreases Pt-CO binding strengthand an increase in reaction rate in excess CO and a rate decrease in excess O2. Photoelectron spectroscopy studies have shown that the valence electron distribution of Pt/TiO2 near the Fermi level varies as a function of TiO2 carrier concentration changes (due to TiO2 film thickness variation), even as Pt remains constant at its Pt0 chemical state. Advisors/Committee Members: Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G.%22%29&pagesize-30">Seebauer, Edmund G. (advisor), Champaign%22%20%2Bcontributor%3A%28%22Saeys%2C%20Mark%22%29&pagesize-30">Saeys, Mark (advisor), Champaign%22%20%2Bcontributor%3A%28%22Kenis%2C%20Paul%20J.A.%22%29&pagesize-30">Kenis, Paul J.A. (Committee Chair), Champaign%22%20%2Bcontributor%3A%28%22Yan%2C%20Ning%22%29&pagesize-30">Yan, Ning (committee member), Champaign%22%20%2Bcontributor%3A%28%22Seebauer%2C%20Edmund%20G.%22%29&pagesize-30">Seebauer, Edmund G. (committee member), Champaign%22%20%2Bcontributor%3A%28%22Saeys%2C%20Mark%22%29&pagesize-30">Saeys, Mark (committee member), Champaign%22%20%2Bcontributor%3A%28%22Jiang%2C%20Jianwen%22%29&pagesize-30">Jiang, Jianwen (committee member), Champaign%22%20%2Bcontributor%3A%28%22Yang%2C%20Hong%22%29&pagesize-30">Yang, Hong (committee member).
Subjects/Keywords: Catalyst; platinum; semiconductor band engineering
Chua, Y. P. G. (2014). Improved catalysts with properties controlled by semiconductor band engineering . (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/46736
Chua, Yong Ping Gavin. "Improved catalysts with properties controlled by semiconductor band engineering." 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 22, 2020. http://hdl.handle.net/2142/46736.
Chua, Yong Ping Gavin. "Improved catalysts with properties controlled by semiconductor band engineering." 2014. Web. 22 Jan 2020.
Chua YPG. Improved catalysts with properties controlled by semiconductor band engineering. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2142/46736.
Chua YPG. Improved catalysts with properties controlled by semiconductor band engineering. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/46736