Solar-Powered Electrochemistry

To make electrochemistry greener, Kevin D. Moeller and his group at Washington University in St. Louis have demonstrated that they can power their reactions with solar energy. Electrochemistry is inherently green because it allows chemists to limit chemical waste by avoiding oxidizing reagents or by recycling catalytic reagents such as transition-metal complexes. But many organic chemists think that electrochemistry requires expensive equipment and avoid it, Moeller said. His lab wanted to show that electrochemistry doesn’t need complicated setups or electricity generated from greenhouse-gas-emitting sources. The researchers bought small photovoltaic cells used to power toy cars and boats for less than $20 apiece. To run reactions, they connected the cells to the positive and negative electrodes in their flasks and then placed the setup in the light. Moeller and his team reproduced the yields of electrochemical reactions they ran previously with a conventional power supply, even difficult amide oxidations, he noted. So far, the reactions have involved direct oxidation of electron-rich compounds. Moeller’s next goal is to use the solar cells to recycle transition-metal reagents.