Synergistic Effect between Rhenium-Zinc Binary Oxides in Catalytic CO 2 Hydrogenation to Methanol

CO2 hydrogenation to methanol utilizing renewable H2 offers a promising route for carbon neutrality, but efficient catalysts with synergistic active sites of H2 and CO2 remain challenging. Herein, we demonstrate a TiO2-supported rhenium-zinc binary oxide catalyst that exhibits methanol selectivity up to ca. 70% at a CO2 conversion of 9.3% and a methanol space-time yield of 529 mg·h−1·gcat−1 at 320 °C and 5 MPa, outperforming ReOx/TiO2 and ZnO/TiO2 catalysts by 5.8 and 2.3 times, respectively. Kinetics analysis combined with structural characterization supports the synergistic effect between dual ReOx and ZnO sites for enhanced performance. Strong Re-Zn interactions generate ReOx sites that are responsible for promoted H2 activation, whereas the highly dispersed, partially reduced ZnO strengthens CO2 adsorption and activation. The activation of CO2 and H2 is decoupled on distinct sites yet coupled via efficient hydrogen supply, thereby accelerating hydrogenation of CO2-derived intermediates. In situ diffuse reflectance infrared Fourier transform spectroscopy reveals a preferred formate pathway, featuring the evolution of b-CO3* to HCOO* and subsequently to H3CO*. This work highlights the synergistic effect between dual oxide sites in promoting selective CO2 conversion to value-added chemicals.