CO<sub>2</sub> Hydrogenation to Methanol over PdZnZr Solid Solution: Effects of the PdZn Alloy and Oxygen Vacancy
Chaojie Huang, Zhaoxuan Wu, Hu Luo, Shunan Zhang, Zilong Shao, Hui Wang, Yuhan Sun
Abstract
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.