Interfacial-Confined Oxygen Vacancy Clusters in ZrO₂-Supported In₂O_{3- x} Catalysts Boost Methanol Production From CO₂

Oxygen vacancies (V_O) play a vital role in catalytic reactions. Tuning the V_O structures beyond its density is of great significance for optimizing catalytic performance, but remains challenging due to uncontrolled reduction and its poor stability under reaction conditions. Here, we report that the integration of quantum size effect for enhanced In₂O₃ reducibility with strong In-O-Zr interfacial confinement for high stability enables the creation of stable large-size V_O clusters (e.g., trimers, tetramers, and larger) on ZrO₂-supported monolayer In₂O_{3- x} nano-islands with high density without overreduction to metallic indium. In the CO₂ hydrogenation reaction, the ZrO₂-supported monolayer In₂O_{3- x} catalyst with V_O clusters exhibits a considerably higher intrinsic activity for methanol production than that of bulk In₂O₃ with single V_O sites. Further addition of Pd onto these monolayer In₂O_{3- x} with enriched V_O clusters allows achieving an unprecedentedly high methanol space-time yield of 46.6 mmol_MeOH·g_cat ^-1 h^-1 at 270 °C along with long-term stability for at least 200 h, surpassing all In₂O₃-based catalysts reported to date.