Tailoring photothermal CO2 hydrogenation by oxide-supported Pt catalysts prepared by flame spray pyrolysis

CO 2 hydrogenation provides a route for carbon utilization and renewable energy storage, but the catalytic behavior of supported Pt catalysts is strongly influenced by the oxide support. Herein, Pt-supported CeO 2 , In 2 O 3 , and TiO 2 catalysts were prepared by flame spray pyrolysis (FSP) to compare support-dependent CO 2 hydrogenation under thermal and light-irradiation conditions. The three reducible semiconductor oxides showed distinct redox properties, optical responses, and surface chemical environments, enabling a comparative evaluation of support effects. Characterization results indicate that the oxide support affects catalyst morphology, surface area, reducibility, light absorption, Pt chemical state, and surface oxygen species. Catalytic tests revealed support-dependent CO 2 conversion and CO/CH 4 selectivity. Under illumination, the measured light-induced temperature rise of approximately 20 °C, but CO 2 conversion was markedly enhanced over all three catalysts. This indicates that the photothermal effect plays an important role in improving catalytic performance, although the extent of improvement still depends on the oxide support. In situ DRIFTS over Pt-TiO 2 provided information on carbonate-, bicarbonate- and CO-related surface species under reaction conditions. This work highlights that both oxide-support selection and photothermal activation are important for optimizing Pt-supported catalysts in CO 2 hydrogenation.