Stanford team uses copper to make sustainable ethanol from CO2
Scientists at Stanford University are making progress in finding sustainable methods of producing ethanol for fuel, without using corn or other crops, according to an article in the Proceedings of the National Academy of Sciences. The team designed copper catalysts that selectively convert CO2 into ethanol and propanol, and grew single crystal-like copper samples up to 600 times bigger than usual to better understand their electrocatalytic performance. The plan is "to create better catalysts that take carbon dioxide as a feedstock and convert it into much more valuable products using renewable electricity or sunlight directly", said scientist Christopher Hahn.

In California, Stanford University scientists reported on a promising technology to make renewable ethanol from water, carbon dioxide and electricity delivered through a copper catalyst. The results are published in the Proceedings of the National Academy of Sciences (PNAS). For the PNAS study, the Stanford team chose three samples of crystalline copper, known as copper (100), copper (111) and copper (751). Scientists use these numbers to describe the surface geometries of single crystals. The study was also written by co-lead author Toru Hatsukade, Drew Higgins and Stephanie Nitopi at Stanford; Youn-Geun Kim at SLAC; and Jack Baricuatro and Manuel Soriaga at the California Institute of Technology.

Scientists would like to design copper catalysts that selectively convert carbon dioxide into higher-value chemicals and fuels, like ethanol and propanol, with few or no byproducts. But first they need a clear understanding of how these catalysts actually work. That’s where the recent findings come in.

“Copper (100), (111) and (751) look virtually identical but have major differences in the way their atoms are arranged on the surface,” said Christopher Hahn, an associate staff scientist at SLAC and co-lead lead author of the study. “The essence of our work is to understand how these different facets of copper affect electrocatalytic performance.”

Ultimately, the Stanford team would like to develop a technology capable of selectively producing carbon-neutral fuels and chemicals at an industrial scale.

“The eye on the prize is to create better catalysts that have game-changing potential by taking carbon dioxide as a feedstock and converting it into much more valuable products using renewable electricity or sunlight directly,” Jaramillo said. “We plan to use this method on nickel and other metals to further understand the chemistry at the surface. We think this study is an important piece of the puzzle and will open up whole new avenues of research for the community.”

Jaramillo also serves at deputy director of the SUNCAT Center for Interface Science and Catalysis, a partnership of the Stanford School of Engineering and SLAC.