The impact of oxide support on the reaction mechanism of copper-based catalysts for CO2 activation

This study investigates the activation mechanism of carbon dioxide in the catalytic hydrogenation to methanol using five copper-based catalyst models: Cu/CeO 2 , Cu/Al 2 O 3 , Cu/SiO 2 , Cu/ZnO, and Cu/MgO. It is observed that the mechanism of CO 2 activation changes with the type of support. In terms of CO 2 adsorption, Cu/Al 2 O 3 exhibits the most significant physical adsorption capacity, while Cu/MgO demonstrates the strongest chemical adsorption characteristics. Furthermore, the stronger the adsorption energy of the catalyst for CO 2 , the greater its charge transfer ability. During the activation of CO 2 , the variation in support type significantly influences the energy barriers of the three activation pathways, thereby altering the CO 2 activation route. The Cu/CeO 2 , Cu/SiO 2 , and Cu/ZnO catalysts activate CO 2 via the HCOO pathway, while the Cu/Al 2 O 3 catalyst also employs the HCOO pathway, and the Cu/MgO catalyst activates CO 2 through the reverse water-gas shift (RWGS) pathway. Among these catalysts, Cu/CeO 2 exhibits the highest catalytic activity, with an activation energy barrier of only 0.490 eV for the HCOO pathway. This indicates the potential of Cu/CeO 2 as a highly efficient catalyst for CO 2 hydrogenation, reinforcing the importance of support selection in catalyst design . • Changing the type of support alters the activation energy barriers for the three pathways of carbon dioxide activation. • The physical adsorption strength of CO 2 follows the order: Cu/Al 2 O 3 > Cu/MgO > Cu/CeO 2 > Cu/ZnO > Cu/SiO 2 . • The Cu/CeO 2 catalyst shows the best performance for activating carbon dioxide through the HCOO pathway.