In situ reconstruction of vegetable sponge-like Bi2O3 for efficient CO2 electroreduction to formate

Abstract

The electrochemical reduction reaction of CO₂ provides a renewable method to close the carbon cycle and alleviate the global energy issue. Bi-based electrocatalysts present huge prospects for catalyzing formate-selective CO₂ reduction. Herein, we fabricated a porous vegetable sponge-like bismuth oxide (VS-Bi₂O₃) for the selective electroreduction of CO₂ to formate, which underwent in situ reconstruction to form 2D nanosheets containing metallic Bi and Bi₂O₂CO₃. We propose that the unique porous morphology and low crystallinity of VS-Bi₂O₃ are beneficial for the in situ generation of Bi₂O₂CO₃, which might play a significant role in enhancing the CO₂ electrocatalysis performance. The catalyst delivers a 93.7% faradaic efficiency of formate at 400 mA cm⁻² and shows stability for over 18 h at 100 mA cm⁻².