Hydroxypillar[5]arene‐Confined Silver Nanocatalyst for Selective Electrochemical Reduction of CO₂ to Ethanol

Abstract

Abstract CO is usually the dominant product on silver‐based catalysts in electrochemical CO 2 reduction reaction (CO 2 RR) possibly due to weak *CO adsorption. In this report, a hydroxypillar[5]arene‐extended porous polymer‐confined silver catalyst (PAF‐PA5‐Ag‐0.8) for electrochemical CO 2 RR which can selectively produce ethanol with a maximum Faradaic efficiency of 55% at 11 mA cm −1 is described. The study reveals that the hydroxypillar[5]arene‐confined Ag clusters are the active sites for ethanol formation. Moreover, temperature‐programmed desorption measurements demonstrate an enhanced adsorption strength of CO* on PAF‐PA5‐Ag‐0.8 compared with that on commercial Ag nanoparticles, which is favored by the C‐C coupling to form ethanol. The density functional theory study indicates that the confined Ag clusters in PAF‐PA5‐Ag‐0.8 contribute to high C 2 selectivity in CO 2 RR through facilitating *COOH formation, stabilizing *CO intermediates, and inhibiting hydrogen evolution. This work provides a new design strategy by modulating *CO adsorption strength on non‐copper electrocatalysts in converting CO 2 into “green” C 2 products.