ZnZrO<sub><i>x</i></sub> Nanoparticles Derived from Metal–Organic Frameworks as Superior Catalysts to Boost CO<sub>2</sub> Hydrogenation to Methanol
Jialing Song, Bin Chen, Juanjuan Bian, Yanmei Cai, Sajid Ali, Dongren Cai, Bingyun Zheng, Jiale Huang, Guowu Zhan
Abstract
ZnZrO x solid solution is a promising catalyst for the hydrogenation of CO 2 to methanol, but precise design of the nanostructure to enhance catalytic performance remains a significant challenge. Herein, a ZnZrO x -based solid solution (ZnZrO x -MD) nanoparticle catalyst with uniform metal dispersion and remarkable CO 2 activation ability was developed via calcination of metal–organic frameworks [MOFs, viz., PCN-223(Zn)] with mixed metal (Zr and Zn) as solid precursors. It was found that the ZnZrO x -MD nanoparticle catalyst outperformed its counterparts prepared using a traditional deposition–precipitation method (ZnZrO x -TD). Furthermore, the effects of the micromorphology and crystal composition on the catalytic performance of ZnZrO x -MD were systematically investigated. Comprehensive characterization results reveal that ZnZrO x -MD contained abundant oxygen vacancies, large specific surface area, and uniform metal dispersion, which collectively contributed to its excellent CO 2 hydrogenation performance, resulting in a high methanol selectivity of 77.2% at 320 °C. In situ DRIFTS experiments confirm the mechanism for the CO 2 hydrogenation to methanol over the ZnZrO x nanoparticle catalysts involved the initial formation of HCOO* species, followed by subsequent hydrogenation to generate CH 3 O* and ultimately produce methanol. Overall, this work highlights the potential benefits of MOFs as thermal decomposition precursors for the fabrication of solid-state catalysts with unique properties.