Surface and Interface Engineering in Copper-Based Bimetallic Materials for Selective CO2 Electroreduction

The electrochemical CO2 reduction reaction (CO2RR) can couple carbon-capture storage with renewable energy to convert CO2 into chemical feedstocks. For this process, copper is the only metal known to catalyze the CO2RR to hydrocarbons with adequate efficiency, but it suffers from poor selectivity. Copper bimetallic materials have recently shown an improvement in CO2RR selectivity compared with that of copper, such that the secondary metal is likely to play an important role in altering inherent adsorption energetics. This review explores the fundamental role of the secondary metal with a focus on how oxygen (O) and hydrogen (H) affinity affect selectivity in bimetallic electrocatalysts. Here, we identify four metal groups categorized by O and H affinities to determine their CO2RR selectivity trends. By considering experimental and computational studies, we link the effects of extrinsic chemical composition and physical structure to intrinsic intermediate adsorption and reaction pathway selection. After this, we summarize some general trends and propose design strategies for future electrocatalysts.