Hydrogen production by glycerol steam reforming over Ni based catalysts prepared by different methods

Ni supported and co-precipitated catalysts promoted by Mg were evaluated for hydrogen production by the glycerol steam reforming. The samples were prepared by incipient wetness impregnation of alumina and by the continuous co-precipitation method. The catalysts were characterized by XRD, S-BET, TPR, NH3-TPD, TPO and SEM/TEM. The catalytic tests were performed in the range from 500 to 650 degrees C in a fixed bed tubular reactor. The gaseous products were analyzed online by gas chromatography. It was found that the partial substitution of Ni by Mg improves the dispersion of Ni, decreases the acidity of the catalysts and increases the resistance to sintering of Ni. The unreduced catalysts presented higher selectivity for H-2 than the previously reduced catalysts. The catalyst unreduced impregnated with 20% Ni showed the highest selectivity in the production of hydrogen (55%), at the temperature of 650 degrees C. Unreduced samples prepared by co-precipitation presented smaller Ni-0 crystallite size after the reaction. The catalyst reduction step is unnecessary for this reaction.