Restraining Interfacial Cu 2+ by Using Amorphous SnO 2 as Sacrificial Protection Boosts CO 2 Electroreduction.

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 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, we report a sacrificial protection strategy to stabilize interfacial crystalline CuO through embedding of active amorphous SnO 2 (c-CuO/a-SnO 2 ) to greatly boost 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 ). The in-situ XAS, XRD tests experiment 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 high active interface significantly lowers energy barrier of the limited step ( * CO 2 → * HCOO) and enhances the selectivity and activity for formate. This article is protected by copyright. All rights reserved.