Photothermal dry reforming of methane (DRM), as an emerging branch of heterogeneous catalysis, could effectively convert CO2 and CH4 into high-value-added chemicals via the synergistic effect between thermochemical and photochemical processes. Herein, we report that loading Rh nanoparticles (NPs) on Ga2O3−x with oxygen vacancies improves CO2 conversion efficiency through photo-assisted DRM. On the Rh/Ga2O3−x catalyst, the photothermal catalytic CO2 conversion rate (112.0 μmol g−1 min−1) is 1.6 times that of the thermal reaction at 500 °C (71.9 μmol g−1 min−1). Rh2O3 and Ga2O3 as precursors are in situ reduced to Rh NPs and Ga2O3−x under the reductive DRM reaction atmosphere, respectively. Characterization results indicate that Rh NPs accelerate the DRM process by enhancing light absorption ability and charge transfer efficiency. Meanwhile, the oxygen vacancies in Ga2O3−x are beneficial for activating reactant molecules rapidly. In situ DRIFTS spectra showed that Rh NPs and oxygen vacancies served as reduction and oxidation sites during the photothermal DRM process. This work paves the way for the rational design of better photothermal catalysts in the future.
