Electrochemical CO2 reduction on few-atomic-layer bismuth nanosheets

Abstract

This work reports on few-atomic-layer thin bismuth nanosheets (BiNSs) prepared via two-step electrodeposition method with Br-as structure-inducing-agent for electrochemical CO2 reduction towards formate. The BiNSs exhibit an impressive CO2 reduction reaction performance of large current density and high Faradic efficiency to produce formate. We further examine the effect of bicarbonate ion migration in CO2 electrochemical reduction process. The magneto-current density and thus the formate yield can be significantly increased in the presence of magnetic field. The CO2 reduction reaction on BiNSs electrodes in magnetic field processes with a high Faradic efficiency over 90% in a wide potential range from −0.68 V to −1.13 V (vs. RHE). Detailed investigation including in-situ spectroscopic analysis, isotopic labeling characterization and ultramicroelectrode voltammetric measurement reveal the total enhancement in electrochemical CO2 reduction capability on BiNSs could be mainly attributed to the magnetic field facilitated spin evolution process along with the magnetohydrodynamic effect. The contribution of spin evolution process and mass transport to the current enhancement indicates the CO2 reduction reaction process can be modulated by kinetic in the further.