Bismuth Oxycarbonates Loaded on Nitrogen-doped Carbon: An Efficient Nanocomposite Catalyst for Electrochemical Reduction of CO2 to Formate

The consumption of fossil fuels has led to a significant increase in CO2 in the atmosphere, resulting in the greenhouse effect and placing tremendous pressure on the global environment. The electrocatalytic reduction of CO2 to produce the high-value chemical formic acid or formate is an efficient and environmentally friendly method with significant practical implications for achieving carbon neutrality. This study presents a nanocomposite catalyst of bismuth oxycarbonate loaded on nitrogen-doped carbon materials (BOC-NC), prepared using a hydrothermal method. In an H-type electrolytic cell, the BOC-NC-900 °C catalyst exhibited an excellent electrochemical reduction of CO2 (CO2RR) performance, achieving a Faradaic efficiency of 94.9% for formate production and maintaining catalytic stability over 38 h of CO2RR at -1.0 V vs. RHE. While in a flow cell configuration, it achieved a current density of 91 mA cm-2, a Faradaic efficiency of 90.5% for the formate, and sustained stability over ten hours at -1.0 V vs. RHE. The synergistic effect generated between BOC and NC enhances the formate selectivity, providing valuable insights for developing composite materials that integrate bismuth-based catalysts with carbon matrices.