Cu/ZnAl2O4 catalysts prepared by ammonia evaporation method: Improving methanol selectivity in CO2 hydrogenation via regulation of metal-support interaction

Numerous studies have demonstrated that improving the metal-support interaction is beneficial for reaction activity and stability in methanol synthesis from CO2. In this research, we deposit Cu onto ZnAl2O4 spinel by the ammonia evaporation method and obtain excellent catalytic performance with methanol selectivity close to 100% at 220 ℃ (STY of methanol: 317 gMeOH·kgcat-1·h−1) at low Cu loading (4 wt%). As opposed to the wet impregnation method, more well-dispersed Cu species are dispersed on the surface of ZnAl2O4 with a higher copper surface area, forming a strong interaction between Cu and ZnAl2O4. And meanwhile the distribution of basic sites is also improved. Thus, the adsorption and activation of CO2 are significantly enhanced. In addition, more Cu+ is readily generated upon reduction due to the fine interaction, which accelerates the stabilization and transformation of methoxy species, promoting the production of methanol.