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

ZnZrO x catalysts have attracted considerable attention for the thermal catalytic hydrogenation of CO 2 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 ZnZrO x was introduced by doping dopants, and the potential of the catalyst for CO 2 -to-methanol conversion was systematically explored via a photothermal coupling strategy. The optimized Sn1Zn2Zr9 catalyst achieved a methanol selectivity of 62.3%, a CO 2 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 CO 2 and H 2, thereby effectively promoting the utilization of both reactants and strengthening the catalytic performance in CO 2 hydrogenation to methanol. These findings provide new insights into oxygen vacancy engineering and photothermal coupling strategies for optimizing ZnZrO x catalysts toward efficient CO 2 hydrogenation to methanol.