Enhanced Electrocatalytic CO2 Reduction of Bismuth Nanosheets with Introducing Surface Bismuth Subcarbonate

The electrocatalytic CO2 reduction reaction (CO2RR) into hydrocarbon products is one of the most promising approaches for CO2 utilization in modern society. However, the application of CO2RR requires optimizing state-of-the-art catalysts as well as elucidating the catalytic interface formation mechanism. In this study, a flower-like nano-structured Bi catalyst is prepared by a facile pulse current electrodeposition method wherein the morphologies could be accurately controlled. Interestingly, nano-structured Bi is inclined to generate Bi2O2CO3 in the air and form a stable Bi2O2CO3@Bi interface, which could enhance the CO2 adsorption and conversion. In-situ Raman spectroscopy analysis also proves the existence of Bi2O2CO3 on the electrode surface. In a practical CO2 reduction test by a flow-cell reactor, the Bi2O2CO3@Bi electrode delivers a high faradaic efficiency of the CO2 to formate/formic acid (~90%) at −1.07 V vs. reversible hydrogen electrode (RHE) with no obvious decay during more than a 10 h continuous test. The introducing surface Bi2O2CO3 in nano-structured Bi supports a promising strategy as well as facile access to prepare improved CO2RR electrocatalysts.