Consecutive sol-gel synthesis of Cu-Zn/Al2O3 catalyst for CO2 Hydrogenation

Cu-Zn/Al2O3 catalyst was prepared by using the consecutive sol-gel method and employed for the hydrogenation of carbon dioxide (CO2) in a closed reaction system reactor. The purpose of this research is to preliminary study the catalytic performance of Cu-Zn/Al2O3 catalyst for CO2 hydrogenation. With an increase in the reaction temperatures, the conversion of CO2 initially increased and then decreased at higher temperatures. Cu-Zn/Al2O3 800°C-5h-cal produced the highest conversion of CO2, 95.40%, at reaction temperature of 220℃ for 2 hours under atmospheric pressure. Physicochemical studies by XRD, XRF, NH3−TPD, CO2−TPD, surface area analyzer and porosity meter showed that the calcination treatment of the catalyst at higher temperature calcination triggered copper and aluminum to form the spinel structure, CuAl2O4 that contributed to the higher catalytic activity. Combined with the catalytic results, we conclude that the increase in the both acidity and basicity are responsible for the catalytic activity on the CO2 hydrogenation.