Microenvironment Engineering for the Electrocatalytic CO 2 Reduction Reaction.

Rather than just focusing on the catalyst itself in the electrocatalytic CO 2 reduction reaction (eCO 2 RR), as previously reviewed elsewhere, we herein extend the discussion to the special topic of the microenvironment around the electrocatalytic center and present a comprehensive overview of recent research progress. We categorize the microenvironment based on the components relevant to electrocatalytic active sites, i.e., the catalyst surface, substrate, co-reactants, electrolyte, membrane, and reactor. Supported by most of the reported articles, the relevant factors affecting the catalytic performance of eCO 2 RR are then discussed in detail, and existing challenges and potential solutions are mentioned. Perspectives for the future research on eCO 2 RR, including the integration of different microenvironment factors, the extension to industrial application by coupling with carbon capture and conversion, and separation of products, are also discussed.