Highly Selective Acidic CO2 Electroreduction with Large Current on Polypyrrole‐Modified Ag Catalyst by Local Microenvironment Modulation

Abstract Electrocatalytic carbon dioxide reduction (CO 2 RR) holds great promise for carbon capture and utilization. In acidic media, CO 2 RR enables efficient CO 2 conversion, but with low selectivity due to the competitive hydrogen evolution reaction (HER) and catalyst corrosion. Herein, conductive polymer polypyrrole (PPy) coated Ag nanoparticles (NPs) catalysts (Ag@PPy) with different thicknesses are designed and synthesized, which could create a hydrophobic environment that reduces the accessibility of H 2 O to the Ag NPs thereby inhibiting HER. The coating of the PPy layer also protects the catalysts from corrosion and improves the stability of the system. Among them, Ag@PPy‐2 with the appropriate thickness showed up to 91.7% for the electrocatalytic reduction of CO 2 to CO and high durability in acidic electrolyte at −300 mA cm −2 . Density functional theory (DFT) calculation shows that Ag nanoparticles coated with PPy not only inhibit the competitive HER, but also reduce the CO 2 RR energy barrier, and improve the efficiency of CO 2 to CO. This study may provide some new ideas for the design of advanced selective electrocatalytic CO 2 reduction catalysts by local microenvironmental engineering.