A Zn regulated Bi nanosheet catalyst for improving electrochemical CO2 reduction to formate over a wide potential window.

Bi-based materials are promising catalysts for electrochemical reduction of carbon dioxide (CO2) to formate, but remain challenging in terms of activity and stability. Herein, we report the facile synthesis of Zn-doped Bi nanosheets (Zn–Bi NSs) as a highly active and robust catalyst for electrochemical reduction of CO2 to formate. Specifically, the Zn–Bi NS catalyst can be obtained using a hydrothermal method to prepare a Zn-decorated Bi2O2CO3 nanosheet followed by electrochemical reduction treatment. The as-prepared catalyst exhibits a remarkable formate faradaic efficiency of 94.6% and a high formate current density of 40.5 mA cm−2 at −1.2 V vs. reversible hydrogen electrode (RHE). In particular, the faradaic efficiency of formate remained at above 90% over a wide potential window from −0.8 to −1.2 V vs. RHE. In the H-type electrolytic cell, the Zn–Bi NS catalyst can be operated stably for 10 h at a cathode potential of −1.0 V vs. RHE with good retention of the physical phase. [ABSTRACT FROM AUTHOR]