Interfacial microenvironments for carbon dioxide electro-upgrading to multicarbon products

Electrocatalytic carbon dioxide (CO2) reduction (eCO2R) to value-added fuels or chemicals, especially multicarbon (C2+) oxygenate and hydrocarbon feedstocks, is a viable approach to close the anthropogenic carbon cycle and power a sustainable society. However, current electrocatalytic systems for eCO2R are not practical for industrialization because of low CO2 mass transport and/or limited activity. In addition to the catalyst, research focus has recently been extended to non-catalyst components in the reaction microenvironment, especially the catalyst-electrolyte interface. This review summarizes the major methods of microenvironment engineering to optimize C2+ selectivity; i.e., catalyst morphology and surface, electrolyte, and electrode structure. The key emphasis is on improving CO2 mass transfer, stabilizing intermediates, and lowering barriers of C−C bond coupling to effectively promote C2+ feedstock evolution. Finally, the critical challenges remaining in this research area and promising directions for future research are addressed.