High-Efficiency Conversion of CO₂ to Oxalate in Water Is Possible Using a Cr-Ga Oxide Electrocatalyst

Abstract

Electrochemical transformation of CO2 into commodity chemicals such as oxalate is a strategy for profitably remediating high atmospheric CO2 levels. Electrocatalysts for oxalate generation, however, have required prohibitively large applied potentials, forcing the use of nonaqueous electrolytes. Here, a thin film comprised of alloyed Cr and Ga oxides on glassy carbon is shown to electrocatalytically generate oxalate from aqueous CO2 with high Faradaic efficiencies at 690 mV overpotential. Oxalate is produced at a surface anion site via a CO-dependent pathway; the process is highly sensitive to the hydrogen-bonding environment and avoids the commonly invoked CO2•– intermediate. Ultimately, this catalytic system accomplishes efficient CO2 to oxalate conversion in protic electrolyte.