Homogeneous Vacancies-Enhanced Orbital Hybridization for Selective and Efficient CO₂-to-CO Electrocatalysis

Crafting vacancies offers an efficient route to upgrade the selectivity and productivity of nanomaterials for CO₂ electroreduction. However, defective nanoelectrocatalysts bear catalytically active vacancies mostly on their surface, with the rest of the interior atoms adiaphorous for CO₂-to-product conversion. Herein, taking nanosilver as a prototype, we arouse the catalytic ability of internal atoms by creating homogeneous vacancies realized via electrochemical reconstruction of silver halides. The homogeneous vacancies-rich nanosilver, compared to the surface vacancies-dominated counterpart, features a more positive d-band center to trigger an intensified hybridization of the Ag_d orbital with the C_P orbital of the *COOH intermediate, leading to an accelerated CO₂-to-CO transformation. These structural and electronic merits allow a large-area (9 cm^-2) electrode to generate nearly pure CO with a CO/H₂ Faradaic efficiency ratio of 6932 at an applied current of 7.5 A. These findings highlight the potential of designing new-type defects in realizing the industrialization of electrocatalytic CO₂ reduction.