Enhanced Interface with Strong Charge Delocalization toward Ultralow Overpotential CO2 Electroreduction

The construction of an interface has been demonstrated as one of the most insightful strategies for designing efficient catalysts toward electrochemical CO 2 reduction (CO 2 RR). However, the weak interfacial interaction and inherent instability inevitably hinder a further performance enhancement in CO 2 RR attributable to the interface effect. Herein, 2 nm Ag nanoclusters (Ag NCs) are embedded onto CeO 2 nanospheres (CeO 2 NSs) with highly interconnected porosity (Ag NCs@CeO 2 NSs) to exclusively study the pure interface effect toward CO 2 RR. The enhanced Ag–CeO 2 pure interface endows Ag NCs@CeO 2 NSs with a remarkably larger current density, significantly higher Faraday efficiency (FE), and energy efficiency as compared to Ag NCs, CeO 2 NSs, and the one with Ag NCs dispersed on CeO 2 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 CO 2 RR to CO at a lower η over Ag NCs@CeO 2 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.