CO₂ Hydrogenation to Methanol over PdZnZr Solid Solution: Effects of the PdZn Alloy and Oxygen Vacancy

Utilization of CO2 with renewable hydrogen to produce value-added chemicals is highly desirable to reduce the dependence on fossil fuels. Methanol is a key intermediate for hydrocarbon products as they require a high methanol selectivity at high temperature to connect the methanol-to-olefin and methanol-to-aromatic processes. To improve the performance of CO2 hydrogenation at a higher temperature, this study prepared a 0.1% Pd/ZnZr catalyst using the coprecipitation method, which showed an 87% methanol selectivity and a space time yield of 735 gmethanol kgcat–1 h–1 at 320 °C, significantly higher than that of the binary ZnZr solid solution (434 gmethanol kgcat–1 h–1). The characterization of the catalyst revealed that Pd2+ species formed a PdZn alloy from the ZrO2 lattice. More oxygen vacancies were generated on the surface, which enhanced the CO2 adsorption and activation capacity and then led to the formation of a higher amount of *HCOO species and better catalytic performance.