Dual-Vacancy Synergy in Vertically Aligned In ₂ O ₃ –MoS ₂ for High-Efficiency CO ₂ Hydrogenation to Methanol

In recent years, In2O3 catalysts have demonstrated high selectivity for CO2-to-methanol conversion at elevated temperatures, while MoS2 exhibits high activity at lower temperatures. Herein, we engineer a vertically aligned In2O3–MoS2 nanocomposite through crystal phase and interface engineering. The vertical growth of MoS2 nanosheets on In2O3 enhances interfacial electron transfer and creates abundant sulfur and oxygen vacancies, which synergistically promote the formation of the key intermediate HCOO* for methanol synthesis. Spectroscopic studies and density functional theory calculations confirm that the vertically aligned interface strengthens the CO2 adsorption and lowers the energy barrier for HCOO* formation. The hexagonal-phase In2O3–MoS2-h catalyst exhibits improved stability and performance, achieving a methanol selectivity of 78.2% and a space-time yield of 0.80 gMeOH gcat.–1 h–1 at 260 °C, outperforming both In2O3-based and MoS2-based benchmarks. In situ and quasi-in situ characterizations reveal that the hexagonal In2O3 phase suppresses structural reconstruction into inactive In2(MoO4)3, thereby preserving active vacancies during the prolonged reaction. This work highlights the crucial role of vertically oriented heterostructures and dual-vacancy synergy in the design of efficient CO2 hydrogenation catalysts.