Preparation and characterization of Ni/CeO2-SiO2 catalysts and their performance in catalytic partial oxidation of methane to syngas

Hexahydrated cerium(III) nitrate (Ce(NO3)3·6H2O) and tetraethyl orthosilicate (C8H20O4Si) were used as the precursors for the synthesis of a series of xCeO2-(1-x)SiO2 (x = 0, 0.25, 0.5, 0.75, 1) composite oxides using a sol-gel process under acidic conditions. The active component, Ni, was loaded on the as-synthesized composite oxides, producing supported Ni catalysts for catalytic partial oxidation of methane to syngas. The properties of the as-synthesized products, such as textural structure, reduction behavior, surface acidity, and carbon deposition, were determined using N2 physical adsorption/desorption, X-ray diffraction, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed reduction by H2, temperature-programmed desorption of NH3, and thermogravimetric analysis. The effects of catalyst composition, calcination temperature, and reaction time on the catalytic performance were investigated. The characterization results showed that these Ni/CeO2-SiO2 catalysts have large surface area, small CeO2 crystals, weak acidity, and low carbon deposition. Highly dispersed NiO is present and is easy to be reduced. The Ni/CeO2-SiO2 catalyst with a Ce/Si molar ratio of 1:1, w(Ni) = 10%, and calcined at 700 °C exhibited good stability and the highest CH4 conversion (∼84%) and CO and H2 selectivity (> 87%).

Graphical AbstractA catalyst consisting of Ni (10%) loaded on a CeO2-SiO2 composite support synthesized using a sol-gel process exhibited high performance in the catalytic partial oxidation of methane to syngas, as a result of its large BET surface area, weak acidity, high dispersion, easy of Ni reduction, and low carbon deposition.Figure optionsDownload full-size imageDownload as PowerPoint slide