Enhanced Interface with Strong Charge Delocalization toward Ultralow Overpotential CO2 Electroreduction

Abstract

The construction of an interface has been demonstrated as one of the most insightful strategies for designing efficient catalysts toward electrochemical CO2 reduction (CO2RR). However, the weak interfacial interaction and inherent instability inevitably hinder a further performance enhancement in CO2RR attributable to the interface effect. Herein, 2 nm Ag nanoclusters (Ag NCs) are embedded onto CeO2 nanospheres (CeO2 NSs) with highly interconnected porosity (Ag NCs@CeO2 NSs) to exclusively study the pure interface effect toward CO2RR. The enhanced Ag–CeO2 pure interface endows Ag NCs@CeO2 NSs with a remarkably larger current density, significantly higher Faraday efficiency (FE), and energy efficiency as compared to Ag NCs, CeO2 NSs, and the one with Ag NCs dispersed on CeO2 nanoparticles. More importantly, an impressively high CO FE of over 70.0% is achieved at an ultralow overpotential (η) of 146 mV. The free energy and differential charge calculations, coupled with X‐ray photoelectron spectroscopy results jointly imply that the effective initiation of CO2RR to CO at a lower η over Ag NCs@CeO2 NSs derives from the enhanced interface‐induced charge delocalization, which enhances the electron transfer ability toward *COOH intermediate, thus overcoming the energy barrier demanded for the rate‐determining step.