A Regenerable Bi-Based Catalyst for Efficient and Stable Electrochemical CO2 Reduction to Formate at Industrial Current Densities.

Abstract

Renewable electricity shows immense potential as a driving force for the carbon dioxide reduction reaction (CO2RR) in production of formate (HCOO-) at industrial current density, providing a promising path for value-added chemicals and chemical manufacturing. However, achieving high selectivity and stable production of HCOO- at industrial current density remains a challenge. Here, we present a robust Bi0.6Cu0.4 NSs catalyst capable of regenerating necessary catalytic core (Bi-O) through cyclic voltammetry (CV) treatment. Notably, at 260 mA cm-2, faradaic efficiency of HCOO- reaches an exceptional selectivity to 99.23 %, maintaining above 90 % even after 400 h, which is longest reaction time reported at the industrial current density. Furthermore, in stability test, the catalyst was constructed by CV reconstruction to achieve stable and efficient production of HCOO-. In 20 h reaction test, the catalyst has a rate of HCOO- production of 13.24 mmol m-2 s-1, a HCOO- concentration of 1.91 mol L-1, and an energy consumption of 129.80 kWh kmol-1. In situ Raman spectroscopy reveals the formation of Bi-O structure during the gradual transformation of catalyst from Bi0.6Cu0.4 NBs to Bi0.6Cu0.4 NSs. Theoretical studies highlight the pivotal role of Bi-O structure in modifying the adsorption behavior of reaction intermediates, which further reduces energy barrier for *OCHO conversion in CO2RR.