Towards understanding of CO2 electroreduction to C2+ products on copper‐based catalysts

The electrochemical CO2 reduction reaction (CO2RR) has been regarded as a promising technique for converting CO2 into high‐value fuels and chemicals. Powered by renewable electricity, the CO2RR provides a viable strategy to mitigate the CO2 concentration in the atmosphere and close the anthropogenic carbon cycle. Recent studies exhibit that copper‐based catalysts are capable of reducing CO2 to C2+ products, such as ethylene and ethanol, which are of higher value compared with C1 products. The reaction process toward C2+ products involves the formation of key intermediate *CO, the C–C bonding, and the post‐C–C bonding to final products. This perspective is focusing on the mechanism leading to C2+ products, examining the evidence from in situ/operando spectroscopy and density functional theory calculations. The effects of Cu facet and electrolyte on catalytic performance are reviewed. An in depth discussion of mechanistic aspects of Cu catalyst is presented, shedding light on the intrinsic features of catalyst and electrode‐electrolyte interface, therefore moving towards an understanding of CO2RR at the atomic level. The electrochemical CO2 reduction reaction has been emerging as a promising technique for converting CO2 to high‐value fuels and chemicals. Copper‐based catalysts are found capable of reducing CO2 to C2+ products efficiently, which draws great interest. In this article, the mechanism of C2+ production on copper catalysts was systematically reviewed, emphasizing the insight from in situ/operando spectroscopy and density functional theory calculations.