Catalytic activity of Ni/SSZ-13 catalyst for CO₂ methanation

Ni/SSZ-13 catalyst was prepared by the impregnation method and used to catalyze CO₂ methanation in a fixed-bed reactor. The microstructure and physical-chemical properties of catalyst were characterized by N₂ physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results show that Ni/SSZ-13 catalyst initiates catalytic activity towards CO₂ methanation at 250 ℃. Ni/SSZ-13 catalyst shows the optimal performance for CO₂ methanation at 450 ℃. CO₂ conversion rate and CH₄ selectivity are 70% and 95%, respectively. SSZ-13 support shows a cuboid structure. Moreover, SSZ-13 support mainly possesses microporous and contains some mesopores, which provide larger surface area for nickel species dispersion. During the reduction process of the calcined catalyst at 500 ℃, NiO is reduced by H₂ into metal Ni, which is the main active component for CO₂ methanation.