CO2reforming of methane over Mg-promoted Ni/SiO2catalysts: the influence of Mg precursors and impregnation sequences

Abstract

Mg-promoted Ni/SiO₂ catalysts with different Mg precursors were prepared by different impregnation sequences and used in CO₂ reforming of methane. The catalysts were characterized by XRD, TPR-H₂, TPD-CO₂, TG-DTA and SEM techniques. The use of Mg(CH₃COO)₂ as Mg precursor favored the performance of the catalyst. The impregnation of Mg(CH₃COO)₂ prior to Ni led to stronger interaction of nickel species with the support and the formation of stable Ni₂SiO₄ and Mg₂SiO₄ species, which inhibited the sintering of metallic Ni and then made the catalyst show better activity and stability. The catalyst thus prepared also exhibited enhanced capacity of CO₂ adsorption, which accelerated the CO₂ activation and the elimination of deposited carbon. No significant carbon deposition was observed on the surface of the catalysts, keeping the catalyst stable.