Photothermal-Driven CO ₂ Hydrogenation to Methanol over Sn-Doped ZnZrO x Catalysts with Abundant Oxygen Vacancies

ZnZrOx catalysts have attracted considerable attention for the thermal catalytic hydrogenation of CO2 to methanol. However, their practical application remains challenging hindered by elevated temperatures and pressures, resulting in unsatisfactory methanol space-time yields (STYs). In conventional oxide-based catalysts, surface oxygen vacancies have been recognized as key active sites that substantially enhance hydrogenation efficiency. Herein, a high concentration of oxygen vacancies in ZnZrOx was introduced by doping dopants, and the potential of the catalyst for CO2-to-methanol conversion was systematically explored via a photothermal coupling strategy. The optimized Sn1Zn2Zr9 catalyst achieved a methanol selectivity of 62.3%, a CO2 conversion of 15.8%, and a methanol STY of 811 mg·g–1·h–1 under mild reaction conditions at 180 °C. It is worth mentioning that this is approximately 1.3 times higher than that obtained under light-free conditions, confirming the positive contribution of light assistance to catalytic performance. Furthermore, density functional theory (DFT) calculations demonstrated that Sn doping reduces the adsorption energy barriers for both CO2 and H2, thereby effectively promoting the utilization of both reactants and strengthening the catalytic performance in CO2 hydrogenation to methanol. These findings provide new insights into oxygen vacancy engineering and photothermal coupling strategies for optimizing ZnZrOx catalysts toward efficient CO2 hydrogenation to methanol.