Dynamic Transformation of Functionalized Bismuth to Catalytically Active Surfaces for CO₂ Reduction to Formate at High Current Densities

A facile strategy to boost the activity and preserve the selectivity of CO 2 reduction to formate using organic‐functionalized metal catalysts, specifically 2‐methyl‐imidazole coordinated to Bi, Bi[2‐MeIm], is reported, and the active surfaces are investigated during structural transformation under the applied cathodic potential necessary for CO 2 reduction. Operando Raman spectroscopy unveils the structure evolution during the reaction and post‐electrolysis analysis shows the formation of three phases of bismuth‐based active surfaces. As a result, Bi[2‐MeIm] achieves an excellent CO 2 reduction performance with an average formate selectivity of ≈90% Faradaic efficiency and high activity reaching a current density of up to −1 A cm −2 in a narrow window of cathodic potentials from −0.46 to −0.78 V versus RHE.