Bismuth Oxides with Enhanced Bismuth-Oxygen Structure for Efficient Electrochemical Reduction of Carbon Dioxide to Formate

Electrochemical conversion of carbon dioxide (CO₂) into high-value chemical products has become a dramatic research area because of the efficient exploitation of carbon resources and simultaneous reduction of atmospheric CO₂ concentration. Herein, we report the bismuth-based catalyst in the efficient electroconversion of CO₂ for the formation of formate with a maximum Faradaic efficiency of 91% and partial current density of ∼8 mA cm^-2 at -0.9 V vs RHE. Experimental and theoretical results show that the bismuth-oxygen structure of bismuth oxides is beneficial for a higher adsorption of CO₂ and the rate-determining route switching from the initial fast pre-equilibrium of electron transfer process to the subsequent hydrogenation step, accompanied by a lower free energy of intermediate. This work may offer valuable insights into crystal structure engineering to achieve efficient electrocatalysts for selective CO₂ reduction toward generation of valuable products.