The impact of oxide support on the reaction mechanism of copper-based catalysts for CO2 activation
Juntian Niu, Ziyu Zhou, Siqi Song, Baihe Guo, Haiyu Liu, Yan Jin, Jingyu Ran
Abstract
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 .