text: Operando spectroscopy is widely applicable to heterogeneous catalysis, which is largely used in industrial chemistry. 
  An example of operando methodology to monitor heterogeneous catalysis is the dehydrogenation of propane with molybdenum catalysts commonly used in industrial petroleum. Mo/SiO and Mo/AlO were studied with an operando setup involving EPR/UV-Vis, NMR/UV-Vis, and Raman. The study examined the solid molybdenum catalyst in real time. It was determined that the molybdenum catalyst exhibited propane dehydrogenation activity, but deactivated over time. The spectroscopic data showed that the most likely catalytic active state was  in the production of propene. The deactivation of the catalyst was determined to be the result of coke formation and the irreversible formation of  crystals, which were difficult to reduce back to . The dehydrogenation of propane can also be achieved with chromium catalysts, through the reduction of  to . Propylene is one of the most important organic starting materials is used globally, particularly in the synthesis of various plastics. Therefore, the development of effective catalysts to produce propylene is of great interest. Operando spectroscopy is of great value to the further research and development of such catalysts.