Durable Cathodes and Electrolyzers for the Efficient Aqueous Electrochemical Reduction of CO2

Abstract The world emits over 14 gigatons of CO 2 in excess of what can be remediated by natural processes annually, contributing to rising atmospheric CO 2 levels and increasing global temperatures. The electrochemical reduction of CO 2 (CO 2 RR) to value‐added chemicals and fuels has been proposed as a method for reusing these excess anthropogenic emissions. While state‐of‐the‐art CO 2 RR systems exhibit high current densities and faradaic efficiencies, research on long‐term electrode durability, necessary for this technology to be implemented commercially, is lacking. Previous reviews have focused mainly on the CO 2 electrolyzer performance without considering durability. In this Review, the need for research into high‐performing and durable CO 2 RR systems is stressed by summarizing the state‐of‐the‐art with respect to durability. Various failure modes observed are also reported and a protocol for standard durability testing of CO 2 RR systems is proposed.