Development of Ni–Ce/Al-MCM-41 catalysts prepared from natural kaolin for CO2 methanation.

We prepared Ni–Ce/Al-MCM-41 catalyst with enhanced activity at low temperatures via one-pot hydrothermal synthesis using kaolin as a silica precursor for CO 2 methanation and investigated the influence of Ce addition on the catalytic activity enhancement. The as-synthesized Al-MCM-41 possessed hexagonal mesoporous silica with a surface area of 436 m²/g and a mesopore of 3.8 nm, allowing the incorporation of Ni and Ce into the Al-MCM-41 structure. In a fixed-bed tubular reactor, the catalytic performance of the as-prepared catalyst was evaluated in terms of CO 2 conversion, CH 4 /CO selectivity, CH 4 yield, reaction rates per catalyst mass (r m), and catalyst surface (r s), TOF, activation energy, and the deactivation rates of its corresponding activities at 250–550 °C and 1 atm. As the Ce content increased, the catalytic activity greatly improved due to the improved Ni dispersion and higher CO 2 adsorption, although the porosity of the catalyst significantly decreased. With the optimum Ce content, 100% CH 4 yield was achieved at 350 °C and weight hourly space velocity (WHSV) = 20,000 mL g⁻¹ h⁻¹. The optimum catalyst also exhibited high stability with a deactivation rate of −0.072% Y CH4 g⁻¹ h⁻¹ over 76 h, attributed to the strong interaction between Ce and Al in Al-MCM-41. [Display omitted] • The MCM-41 could be prepared from natural kaolin. • The MCM-41 possessed high surface area of 436 m²/g and mesopore of 3.8 nm. • The optimum catalyst provided the CH 4 yield of 100% at 350 °C. • The optimum catalyst exhibited a high stability over 76 h. • The high stability of catalyst was attributed to the strong interaction between Ce and Al. [ABSTRACT FROM AUTHOR]