Activating Bismuth Nanosheets for Electrochemical CO₂ Reduction by Strain Engineering

Upgrading waste CO₂ has been a hot topic due to environmental problems. Bismuth with low cost was ideal for the electrochemical CO₂ reduction reaction (CO₂RR) to HCOO^-. Numerous methods have been proposed to boost the electrochemical CO₂RR performance by reducing the thickness and facet of bismuth nanostructures. However, control of the catalytic activity of bismuth nanostructures via electronic structure and revealing of corresponding mechanisms remains challenging. Here, we reported that engineering the electronic structure of bismuth nanosheets via compressive strain boosts the catalytic performance though electrochemical method. An electrochemical cathodic method was conducted to produce bismuth nanosheets with compressive strain of ∼0.6%, which showed high electrocatalytic efficiency for HCOO^- formation from CO₂ reduction reaction (>90%) with a wide potential range (700 mV). The excellent catalytic performance could be attributed to the compressive strain introduced during the electrochemical intercalation process. Density functional theory revealed that the compressive strain could engineer the electronic structure of the bismuth, allowing optimized binding of OCHO^* species. Our findings open up a new avenue for the development of next-generation high-performance CO₂RR electrocatalysts via strain engineering.