Interfacial-Confined Oxygen Vacancy Clusters in ZrO2-Supported In2O3- x Catalysts Boost Methanol Production From CO2.

Oxygen vacancies (VO) play a vital role in catalytic reactions. Tuning the VO 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 VO clusters (e.g., trimers, tetramers, and larger) on ZrO2-supported monolayer In2O3- x nano-islands with high density without overreduction to metallic indium. In the CO2 hydrogenation reaction, the ZrO2-supported monolayer In2O3- x catalyst with VO clusters exhibits a considerably higher intrinsic activity for methanol production than that of bulk In2O3 with single VO sites. Further addition of Pd onto these monolayer In2O3- x with enriched VO clusters allows achieving an unprecedentedly high methanol space-time yield of 46.6 mmolMeOH·gcat -1 h-1 at 270 °C along with long-term stability for at least 200 h, surpassing all In2O3-based catalysts reported to date.