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

The world emits over 14 gigatons of CO₂ in excess of what can be remediated by natural processes annually, contributing to rising atmospheric CO₂ levels and increasing global temperatures. The electrochemical reduction of CO₂ (CO₂ RR) to value-added chemicals and fuels has been proposed as a method for reusing these excess anthropogenic emissions. While state-of-the-art CO₂ 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 CO₂ electrolyzer performance without considering durability. In this Review, the need for research into high-performing and durable CO₂ 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 CO₂ RR systems is proposed.