Carbon dioxide hydrogenation for value-added chemicals has been regarded as a promising way for CO 2 utilization. This paper describes the preparation of Ni/CeO 2 catalysts derived from Ce-MOF precursor by impregnation or one-pot method and their application in carbon dioxide methanation. Various techniques were employed to characterize the prepared catalysts, including N 2 adsorption–desorption, X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (SEM), H 2 -temperature programmed reduction (H 2 -TPR), H 2 -temperature programmed desorption (H 2 -TPD) and CO 2 -temperature programmed desorption (CO 2 -TPD). The results showed that compared with commercial CeO 2 and CeO 2 prepared by precipitation, CeO 2 derived from Ce-MOF exhibited more oxygen vacancies and lower temperature reducibility, making it more beneficial for the adsorption and activation of CO 2 . Consequently, nickel supported on rod-shaped CeO 2 derived from Ce-MOF exhibited higher CO 2 conversion and methane selectivity at low temperatures. Furthermore, the Ni/CeO 2 −M-1 catalysts prepared by one-pot method showed superior activity since nickel could be partially incorporated into ceria lattice, leading to the formation of Ce 1-x Ni x O 2-y solid solutions and oxygen vacancies. The effect of nickel loading on the properties of the catalysts by one-pot method was also investigated, and the optimum Ni loading was 15 wt.% owing to the maximum number of oxygen vacancies being reached.
CO 2 hydrogenation to chemicals and fuels is a significant approach for achieving carbon neutrality. It is essential to rationally design the chemical structure and catalytic active sites towards the development of efficient catalysts. Here we show a Ce-CuZn catalyst with enriched Cu/Zn-O V -Ce active sites fabricated through the atomic-level substitution of Cu and Zn into Ce-MOF precursor. The Ce-CuZn catalyst exhibits a high methanol selectivity of 71.1% and a space-time yield of methanol up to 400.3 g·kg cat −1 ·h −1 with excellent stability for 170 h at 260 °C, comparable to that of the state-of-the-art CuZnAl catalysts. Controlled experiments and DFT calculations confirm that the incorporation of Cu and Zn into CeO 2 with abundant oxygen vacancies can facilitate H 2 dissociation energetically and thus improve CO 2 hydrogenation over the Ce-CuZn catalyst via formate intermediates. This work offers an atomic-level design strategy for constructing efficient multi-metal catalysts for methanol synthesis through precise control of active sites.
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