Photo-Assisted Catalytic CO2 Hydrogenation to CO with Nearly 100% Selectivity over Rh/TiO2 Catalysts

Photo-assisted catalytic CO 2 hydrogenation represents a promising route to convert CO 2 into value-added chemicals under mild conditions, but challenges remain in the design and development of highly active and selective catalysts. Herein, we synthesized highly efficient catalysts comprising Rh nanoparticles supported on TiO 2 nanosheets for photo-assisted catalytic CO 2 hydrogenation, which achieved a high CO production rate of 20.6 mmol g cat –1 h –1 (5.15 mol g Rh –1 h –1 ) with nearly 100 % selectivity and excellent stability at 250 °C under light irradiation, outperforming most reported metal-based catalysts. X-ray photoelectron spectroscopy revealed that the electrons transfer from Rh nanoparticles to TiO 2, hinting a strong interaction between Rh and the TiO 2 support. Under illumination, the accumulated hot electrons on TiO 2 surfaces could effectively promote the activation of CO 2 molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy results revealed that formate was the critical intermediate in the reverse water–gas shift reaction process, and light irradiation could effectively facilitate the activation and conversion of reactants and intermediate species, thereby improving CO production. This work provides a new strategy for the integration of solar and thermal energy for an efficient RWGS reaction under mild conditions.