Three-Phase-Heterojunction Cu/Cu 2 O-Sb 2 O 3 Catalyst Enables Efficient CO 2 Electroreduction to CO and High-Performance Aqueous Zn-CO 2 Battery.

Zn-CO 2 batteries are excellent candidates for both electrical energy output and CO 2 utilization, whereas the main challenge is to design electrocatalysts for electrocatalytic CO 2 reduction reactions with high selectivity and low cost. Herein, the three-phase heterojunction Cu-based electrocatalyst (Cu/Cu 2 O-Sb 2 O 3 -15) is synthesized and evaluated for highly selective CO 2 reduction to CO, which shows the highest faradaic efficiency of 96.3% at -1.3 V versus reversible hydrogen electrode, exceeding the previously reported best values for Cu-based materials. In situ spectroscopy and theoretical analysis indicate that the Sb incorporation into the three-phase heterojunction Cu/Cu 2 O-Sb 2 O 3 -15 nanomaterial promotes the formation of key * COOH intermediates compared with the normal Cu/Cu 2 O composites. Furthermore, the rechargeable aqueous Zn-CO 2 battery assembled with Cu/Cu 2 O-Sb 2 O 3 -15 as the cathode harvests a peak power density of 3.01 mW cm -2 as well as outstanding cycling stability of 417 cycles. This research provides fresh perspectives for designing advanced cathodic electrocatalysts for rechargeable Zn-CO 2 batteries with high-efficient electricity output together with CO 2 utilization.