In Situ Bismuth Nanosheet Assembly for Highly Selective Electrocatalytic CO2 Reduction to Formate

Abstract The reduction of carbon dioxide (CO2) into value‐added fuels using an electrochemical method has been regarded as a compelling sustainable energy conversion technology. However, high‐performance electrocatalysts for CO2 reduction reaction (CO2RR) with high formate selectivity and good stability need to be improved. Earth‐abundant Bi has been demonstrated to be active for CO2RR to formate. Herein, we fabricated an extremely active and selective bismuth nanosheet (Bi‐NSs) assembly via an in situ electrochemical transformation of (BiO)2CO3 nanostructures. The as‐prepared material exhibits high activity and selectivity for CO2RR to formate, with nearly 94% faradaic efficiency at −1.03 V (versus reversible hydrogen electrode (vs. RHE)) and stable selectivity (>90%) in a large potential window ranging from −0.83 to −1.18 V (vs. RHE) and excellent durability during 12 h continuous electrolysis. In addition, the Bi‐NSs based CO2RR/methanol oxidation reaction (CO2RR/MOR) electrolytic system for overall CO2 splitting was constructed, evidencing the feasibility of its practical implementation.