In situ fabricating a Rh/Ga2O3 photothermal catalyst for dry reforming of methane

Abstract

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 Ga₂O_3−x with oxygen vacancies improves CO₂ conversion efficiency through photo-assisted DRM. On the Rh/Ga₂O_3−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 Ga₂O_3−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 Ga₂O_3−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.