Introduction of sulfur in Bi2O3 to boost water activation for enhancing the reduction of CO2 to formate

The reduction of carbon dioxide to produce valuable chemicals offers a sustainable approach towards achieving carbon neutralization. However, the electrochemical carbon dioxide reduction (ECO2RR) using clean electricity faces challenges in terms of high product faradaic efficiency (FE), current density, and stability. In this study, we prepared a S–Bi2O3 nanosheets (NS) catalyst through in-situ structural reconstruction. The S–Bi2O3 NS catalyst exhibited a peak formate FE of 92.05 % at −0.9 V and a high formate formation rate of 497.80 μmol h−1 cm−2 at −1.3 V. The significant improvement in selectivity and activity is attributed to the sulfur modification on Bi2O3 NS catalyst. The sulfur doping enhances the dissociation of water into H* species, facilitating the formation of HCOO* intermediate and promoting formate production. This work presents a simple and effective strategy for developing highly selective Bi-based electrocatalysts for efficient formate production.