Combining the Active Site Construction and Microenvironment Regulation via a Bio‐Inspired Strategy Boosts CO2 Electroreduction Under Ampere‐Level Current Densities

Electrochemical reduction of CO₂ reaction (CO₂RR) is recognized as a complicated process involving multiple steps on the gas^-electrode-solution interface. Hence, it is equally important to construct highly efficient active sites and regulate favorable microenvironments around the reaction interface. Herein, we propose a bio-inspired strategy to address both issues simultaneously in one catalytic system. We first evaporate isolated Au sites on the surface of the Cu layer to tune the intrinsic activity of the Cu catalyst, then fix hexanethiol (HEX) molecules onto the Au sites through Au─S bonds to regulate reaction microenvironments (CuAu-HEX). Specifically, those Au/Cu bimetallic active sites can decrease the energy barriers for the C─C coupling procedure and accelerate the generation of multicarbon products. More importantly, those stable and nondense HEX molecules on Au sites can ensure long-term hydrophobicity and high local concentration of CO₂ around active sites, rather than block the channels for reactant transfer. Consequently, this unique structure is favorable for the pathways toward multicarbon products, generating >70% Faradaic efficiencies (FE) for multicarbon products even at 1 A cm^-2. Intriguingly, this modification layer is very similar to animal hair follicles, which might present a new strategy to regulate the interfacial environments in various electrocatalytic reactions.