CO ₂ Hydrogenation over MOF-74-Based Catalysts: Role of Physical Mixing and Mg-MOF-74 as a Support

MOF-derived catalysts were prepared by physical mixing of Ni-MOF-74 and Mg-MOF-74. Catalytically active Ni metal particles were generated upon thermal treatment of Ni-MOF-74 (acting as a precursor), while Mg-MOF-74 functions as a stable catalyst support with a high CO₂ adsorption capacity. The resulting 50Ni50Mg-MOF-74-derived catalyst exhibited superior performance in CO₂ hydrogenation to CH₄ at 350 °C compared to catalysts derived solely from Ni-MOF-74. The thermal stability of Mg-MOF-74 was confirmed through X-ray diffraction and TG-DTA, while the formation of well-dispersed Ni metal particles was shown by transmission electron microscopy and HAADF-STEM measurements. Molecular dynamics simulation also indicates the formation of Ni metal particles from Ni-MOF-74 and the high stability of Mg-MOF-74. The catalyst prepared by physical mixing demonstrated high activity and durability for the CO₂ hydrogenation reaction over 50 h.