Promotion of C─C Coupling in the CO ₂ Electrochemical Reduction to Valuable C ₂₊ Products: From Micro‐Foundation to Macro‐Application

Abstract The electrochemical CO ₂ reduction reaction (CO ₂ RR) to valuable C ₂₊ products emerges as a promising strategy for converting intermittent renewable energy into high‐energy‐density fuels and feedstock. Leveraging its substantial commercial potential and compatibility with existing energy infrastructure, the electrochemical conversion of CO ₂ into multicarbon hydrocarbons and oxygenates (C ₂₊ ) holds great industrial promise. However, the process is hampered by complex multielectron‐proton transfer reactions and difficulties in reactant activation, posing significant thermodynamic and kinetic barriers to the commercialization of C ₂₊ production. Addressing these barriers necessitates a comprehensive approach encompassing multiple facets, including the effective control of C─C coupling in industrial electrolyzers using efficient catalysts in optimized local environments. This review delves into the advancements and outstanding challenges spanning from the microcosmic to macroscopic scales, including the design of nanocatalysts, optimization of the microenvironment, and the development of macroscopic electrolyzers. By elucidating the influence of the local electrolyte environment, and exploring the design of potential industrial flow cells, guidelines are provided for future research aimed at promoting C─C coupling, thereby bridging microscopic insights and macroscopic applications in the field of CO ₂ electroreduction.