Developing Ni-based CO2 methanation catalysts with enhanced low-temperature activities via constructing advantageous mesoporous CeO2 nanosphere support

In this work, the advantageous mesoporous CeO2 nanosphere with large specific surface area up to 190.4 m2/g was facilely prepared using an improved hydrothermal method. The obtained mesoporous CeO2 nanosphere was used as the support for Ni-based CO2 methanation catalysts. The effects of Ni loading, structural properties, and redox characteristics on the catalytic performances were systematically investigated. The catalyst with 20 wt% Ni loading supported on mesoporous CeO2 nanosphere demonstrated exceptional low-temperature activity. A comprehensive suite of characterization techniques, including XRD, N2 physisorption, SEM, XPS, H2-TPR, CO2-TPD, in-situ DRIFTS, and online TPSR, were utilized to elucidate the underlying reasons for the superior performance. The superior activity of the Ni-based catalyst was attributed to the large specific surface area, mesoporous structure, and excellent redox properties of the mesoporous CeO2 nanosphere support. In contrast, Nibased catalysts supported on commercial materials (e.g., SiO2, Al2O3, CeO2) exhibited poor low-temperature performance due to severe thermal sintering of metallic Ni active sites and inferior redox properties. Therefore, the present mesoporous CeO2 nanosphere with large specific surface area, advantageous redox property, and abundant surface oxygen vacancies are promising supports for Ni-based catalysts, enhancing low-temperature CO2 methanation performance and potentially benefiting other reactions.