Oxygen vacancy-engineered In2O3@carbon catalysts from steam-pyrolyzed MOFs for photothermal CO2 hydrogenation

Photothermal CO2 hydrogenation has attracted considerable attention as a promising approach to utilize carbon dioxide through the efficient conversion of solar energy into chemicals and fuels. In this study, we report a novel approach to improve the catalytic performance of indium oxide-based catalysts for the photothermal reverse water-gas shift (RWGS) reaction. Catalysts derived from the steam pyrolysis of the metal-organic framework MIL(In)-68 display a high density of oxygen vacancies and defect sites on the In2O3 surface. These features significantly enhance CO2 adsorption and H2 dissociation ability while maintaining the porosity of the material and enhancing its photothermal properties. Among the catalysts investigated, the Rb-promoted catalyst exhibited superior activity, achieving CO production rates of 53 mmol gIn2O3-1 h-1 with 100% selectivity without any external heating. Comprehensive characterization, including XPS and Raman spectroscopy, confirmed that steam-pyrolysis leads to extensive defective site formation, resulting in improved catalytic performance. These results highlight the potential of steam-pyrolyzed MOF materials as efficient and selective catalysts for photothermal CO2 hydrogenation, offering a sustainable route to valuable chemical production.