Assessing the potential of xNi-yMg-Al2O3 catalysts prepared by EISA-one-pot synthesis towards CO2 methanation

Abstract

Mesoporous xNi-yMg-Al2O3 catalysts prepared by combined evaporation induced self-assembly (EISA) and one-pot techniques were tested in CO2 methanation reaction. All calcined/reduced materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), N2 physisorption, thermogravimetric analysis (TGA), CO2 adsorption, H2 temperature programmed reduction (H2-TPR) and transmission electron microscopy (TEM). The effects of Mg and Ni loadings on the catalysts properties and performances were systematically studied. Higher Mg contents enhanced methanation performances due to more favourable metallic interactions between the Ni, Mg and Al species. In addition, higher Ni contents led to better selectivity to CH4 by enhancing methane formation that involves H2 dissociation on Ni0 sites. The mesoporous 5Ni–Al2O3 catalyst obtained by the EISA-one-pot technique was significantly more active than silica-based catalysts with same 5 wt% Ni content supported on USY zeolite and SBA-15. Moreover, the performances of the most promising 15Ni–7Mg–Al2O3 mesoporous material were similar to those of a commercial 25Ni/γ-Al2O3 catalyst in spite of its reduced nickel content.