Nitrogen Dopant Induced Highly Selective and Durable CO₂ Electroreduction into Formate on the In₂O₃ Surface

The inactive and unstable active sites limit the development of the electrochemical CO₂ reduction reaction (CO₂RR) under a large current density. Herein, nitrogen-doped In₂O₃ was designed, which achieved a formate Faradaic efficiency (FE_formate) of 97.6% with a formate partial current density (<i>j</i>_formate) of 390.6 mA cm^-2. Moreover, it maintained an FE_formate above 90% for over 20 h at 200 mA cm^-2 in a flow cell, while pristine In₂O₃ lost CO₂RR activity within 4 h. It was found that nitrogen doping induced the electrons to transfer from the catalyst to the reactant molecules more easily and quickly to avoid the corrosion of the catalyst caused by electron accumulation. Meanwhile, the nitrogen dopant favored the adsorption of *CO₂^- intermediates in the form of the OC*O*^- adsorption mode and promoted the formation of formate-related *CO₂^- and *OCHO intermediates at lower potentials, thus facilitating formate production. This fundamental insight aids in the development of highly active catalysts with ultrastability under a large current density.