Effect of preparation method on the performance of Ni/MgO-SiO2 catalysts for glycerol steam reforming

Catalysts were prepared with 10 wt% of Ni(II) and 30 wt% of MgO over commercial SiO2, using dry (physical mixture) and wet (impregnation with different polarities solvents: ethanol and acetone) sequential processes. The characterization techniques used were energy dispersive X-ray spectroscopy, nitrogen physisorption, X-ray diffractometry, H-2 temperature-programmed reduction, X-ray diffractometry in situ with H-2, H-2 temperature-programmed desorption, and scanning electron microscopy. In order to verify activity, selectivity, and carbon deposition, the catalysts were tested in glycerol steam reforming reaction at 600 degrees C, for 5 h, at a 12:1 water:glycerol molar ratio. After the reactions, the catalysts were submitted to thermogravimetric analysis, X-ray diffractometry, and scanning electron microscopy, in order to characterize the carbon deposits during the catalytic process. Impregnation solvent polarity influenced the metallic dispersion and the metallic area of the catalysts, given that, the lower the polarity of the solvent, the higher the metallic dispersion and the area, and the lesser the carbon deposition during the reaction. The material that presented the best catalytic performance in terms of H-2 output and carbon deposition was the catalyst prepared with ethanol as impregnation solvent (less polar solvent), as a consequence of its greater dispersion and larger metallic area. (C) 2018 Published by Elsevier Ltd on behalf of Energy Institute.