Copper as an Electron Hunter for Enhancing Bi 2 O 2 CO 3 Electrocatalytic CO 2 Conversion to Formate.

Cu-doped Bi 2 O 2 CO 3 catalyst with copper (Cu) acting an electron hunter for conversion of carbon dioxide into formate is developed. The Cu-Bi 2 O 2 CO 3 catalyst with hollow microsphere structure extends the duration of CO 2 retention on the catalyst, providing a greater number of active sites. It exhibits remarkable performance with conversion efficacy of 98.5% and current density of 800 mA cm -2 across a wide potential window (-0.8 to -1.3 V vs RHE). Density functional theory investigations reveal that the presence of copper (Cu) significantly enhances the charge density at the active sites and influences the local electronic structure of bismuth (Bi), thereby reducing the energy barrier associated with the transformation of *OCHO species into formate.