Now, as reported in the journal Nature Energy, researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) have improved the process’s selectivity by developing a new approach to modify the surface of the copper catalysts used to assist the reaction.
“Although we know copper is the best catalyst for this reaction, it doesn’t give high selectivity to the desired products,” said Alexis Bell, a faculty senior scientist in Berkeley Lab’s Chemical Sciences Division and professor of chemical engineering at UC Berkeley. “Our group has found that you can do various tricks with the local environment of the catalyst to provide that selectivity.”
In previous studies, the researchers had established the precise conditions that gave the best electrical and chemical environment for creating commercially interesting carbon-rich products. But those conditions are contrary to those that naturally occur in a typical fuel cell, which uses a water-based conductive material.
To pinpoint a design that could be used in the aqueous environment of fuel cells, Bell and his team, as part of the Department of Energy’s Liquid Sunlight Alliance Energy Innovation Hub project, turned to thin layers of ionomers, polymers that allow certain charged molecules (ions) to pass through while excluding others. As a result of their highly selective chemistry, they are uniquely suited to have a strong influence on the microenvironment.