Restraining Interfacial Cu²⁺ by using Amorphous SnO₂ as Sacrificial Protection Boosts CO₂ Electroreduction

Abstract

Abstract The electrochemical carbon dioxide reduction reaction (CO 2 RR) to formate is of great interest in the field of electrochemical energy. Cu‐based material is an appealing electrocatalyst for the CO 2 RR. However, retaining Cu 2+ under the high cathodic potential of CO 2 RR remains a great challenge, leading to low electrocatalytic selectivity, activity, and stability. Herein, inspired by corrosion science, a sacrificial protection strategy to stabilize interfacial crystalline CuO through embedding of active amorphous SnO 2 (c‐CuO/a‐SnO 2 ) is reported, which greatly boosts the electrocatalytic sensitivity, activity, and stability for CO 2 RR to formate. The as‐made hybrid catalyst can achieve superior high selectivity for CO 2 RR to formate with a remarkable Faradaic efficiency (FE) of 96.7%, and a superhigh current density of over 1 A cm −2 that far outperforms industrial benchmarks (FE > 90%, current density > 300 mA cm −2 ). In situ X‐ray absorption spectroscopy (XAS) and X‐ray diffractionexperimental and theoretical calculation results reveal that the broadened s‐orbital in interfacial a‐SnO 2 offers the lower orbital for extra electrons than Cu 2+ , which can effectively retain nearby Cu 2+ , and the high active interface significantly lowers the energy barrier of the limited step ( * CO 2 → * HCOO) and enhances the selectivity and activity for CO 2 RR to formate.