Comparative Study of Ce-MOF-Derived Mesoporous CeO₂ Architectures for Enhanced CO₂ Methanation over Ni/CeO₂ Catalysts

Metal-organic frameworks (MOFs) are promising precursors for constructing high-performance catalysts due to their ordered porous architectures, high surface areas, and tunable compositions. In this work, mesoporous CeO₂ supports derived from Ce-BTC, Ce-UiO-66, and Ce-BDC were prepared and used to construct 10 wt % Ni/CeO₂ catalysts for CO₂ methanation. The catalysts were characterized by XRD, SEM, TEM, XPS, H₂-TPR, CO₂-TPD, and in situ DRIFTS to investigate their structural properties, redox behavior, and reaction mechanism. Compared with the commercial CeO₂-supported catalyst (10Ni/CeO₂-C), the Ce-MOF-derived mesoporous CeO₂-supported catalysts exhibited significantly enhanced performance. At 330 °C, the CO₂ conversions over 10Ni/CeO₂-BTC, 10Ni/CeO₂-BDC, and 10Ni/CeO₂-UiO-66 reached 86.0%, 85.3%, and 82.8%, respectively, substantially higher than that of 10Ni/CeO₂-C (57.0%). The corresponding CH₄ selectivity reached 99.8%, 99.8%, and 99.7%, respectively, also superior to that of 10Ni/CeO₂-C (98.7%). The superior activity was attributed to the inherited mesoporous framework, enlarged specific surface area, and strengthened metal-support interaction, which collectively promoted Ni dispersion, CO₂ adsorption/activation, and H₂ dissociation. The in situ DRIFTS results indicated that CO₂ methanation over these catalysts predominantly proceeded via a formate-mediated pathway. These findings provided new insights into the rational design of high-performance Ni-based catalysts for CO₂ methanation.