Modulating Oxygen Vacancies via Ag Induced Interfacial Electron Transfer in SnO 2 for CO 2 Electroreduction

ABSTRACT Regulating oxygen vacancies (O v ) in SnO 2 to facilitate high‐efficiency carbon dioxide electroreduction reduction reaction (CO 2 RR) is still a significant challenge. Therefore, a strategy based on Ag‐induced interfacial electron transfer was proposed to modulate O v in SnO 2 for CO 2 electroreduction. The prepared Ag/SnO 2 with an optimal O v content delivers a formate Faradaic efficiency (FE) of 94.2% at −0.9 V versus RHE and maintains a formate FE of over 80% from −0.8 to −1.2 V versus RHE. Ag constructs a consecutive Ag/SnO 2 interface, inducing spontaneous electron transfer from Ag to SnO 2 . This interfacial charge transfer weakens surface Sn‐O bonds, thereby lowering the formation energy of oxygen vacancies (O v ) from 2.532 to 0.223 eV. The synergistic interaction between the Ag/SnO 2 interface and O v facilitates the formation of electron‐rich Sn active sites. The tailored Sn sites selectively stabilize the *OCHO intermediate (Δ G *OCHO = −0.320 eV) while suppressing the hydrogen evolution reaction (Δ G *H = 0.464 eV), thereby enabling efficient CO 2 ‐to‐formate conversion. This work paves the way for designing efficient Sn‐based catalysts via synergistic interface and oxygen vacancy engineering.