Synthesis, characterization and catalytic application of Ni catalysts supported on alumina-zirconia mixed oxides

摘要

Alumina and alumina-zirconia mixed oxides were compared as supports to prepare nickel catalysts. The oxides were prepared by the sol-gel method using aluminum tri-sec-butoxide and zirconium (IV) propoxide as precursors, and its physicochemical properties were determined by BET, TGA, DTA, XRD, SEM and TEM. The catalysts of nickel were obtained by the impregnation of the supports with nickel nitrate (10 wt%) and were heat-treated at 700 degrees C. The specific area of the supports and catalysts decreased with the increase in the zirconia content in agreement with the crystalline phase formed. TEM micrographs of nickel catalysts revealed particles in the size range of 10-30 nm. The Ni/Al2O3-ZrO2 catalysts were tested in the steam reforming reaction of ethanol (SRE) at 500 degrees C, and the obtained results suggest that the differences in catalytic activities depended on the content of ZrO2. The selectivity towards H-2 was similar to 56% for the named catalyst Ni-Al-0.25Zr.