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

CO 2 hydrogenation to methanol utilizing renewable H 2 offers a promising route for carbon neutrality, but efficient catalysts with synergistic active sites of H 2 and CO 2 remain challenging. Herein, we demonstrate a TiO 2 -supported rhenium-zinc binary oxide catalyst that exhibits methanol selectivity up to ca. 70% at a CO 2 conversion of 9.3% and a methanol space-time yield of 529 mg·h −1 ·g cat −1 at 320 °C and 5 MPa, outperforming ReO x /TiO 2 and ZnO/TiO 2 catalysts by 5.8 and 2.3 times, respectively. Kinetics analysis combined with structural characterization supports the synergistic effect between dual ReO x and ZnO sites for enhanced performance. Strong Re-Zn interactions generate ReO x sites that are responsible for promoted H 2 activation, whereas the highly dispersed, partially reduced ZnO strengthens CO 2 adsorption and activation. The activation of CO 2 and H 2 is decoupled on distinct sites yet coupled via efficient hydrogen supply, thereby accelerating hydrogenation of CO 2 -derived intermediates. In situ diffuse reflectance infrared Fourier transform spectroscopy reveals a preferred formate pathway, featuring the evolution of b-CO 3 * to HCOO* and subsequently to H 3 CO*. This work highlights the synergistic effect between dual oxide sites in promoting selective CO 2 conversion to value-added chemicals.