Coordinating the Edge Defects of Bismuth with Sulfur for Enhanced CO2 Electroreduction to Formate

Bismuth-based materials have been recognized as promising catalysts for the electrocatalytic CO2 reduction reaction (ECO2RR). However, they show poor selectivity due to competing hydrogen evolution reaction (HER). In this study, we have developed an edge defect modulation strategy for Bi by coordinating the edge defects of bismuth (Bi) with sulfur, to promote ECO2RR selectivity and inhibit the competing HER. The prepared catalysts demonstrate excellent product selectivity, with a high HCOO- Faraday efficiency of approximate to 95 % and an HCOO- partial current of approximate to 250 mA cm(-2) under alkaline electrolytes. Density function theory calculations reveal that sulfur tends to bind to the Bi edge defects, reducing the coordination-unsaturated Bi sites (*H adsorption sites), and regulating the charge states of neighboring Bi sites to improve *OCHO adsorption. This work deepens our understanding of ECO2RR mechanism on bismuth-based catalysts, guiding for the design of advanced ECO2RR catalysts.

Automated summary

In this study, a catalyst with excellent selectivity for electrocatalytic CO2 reduction reaction (ECO2RR) and inhibition of competing hydrogen evolution reaction (HER) has been developed by coordinating the edge defects of bismuth (Bi) with sulfur. The catalyst exhibits high product selectivity, with a HCOO- Faraday efficiency of approximately 95% and an HCOO- partial current of approximately 250 mA cm(-2) under alkaline electrolytes. Density function theory calculations reveal the mechanism behind the improved selectivity and provide guidance for the design of advanced ECO2RR catalysts based on bismuth.