Hydrogen Production by Glycerol Steam Reforming on the Ni/CaO-Al2O3 Catalysts: The Study of Synergistic Effect Between CaO and Al2O3.

Ni catalysts impregnated on CaO–Al2O3 with various Al/Ca molar ratios were synthesized, and employed in the glycerol steam reforming process to investigate the effect of calcium content on the catalyst efficiency. The prepared catalysts were characterized by XRD, BET, H2-TPR, CO2-TPD and SEM analyses. According to the preliminary tests, the characteristic features of the catalysts were directly affected by the Al/Ca molar ratio. The specific surface area and total pore volume increased with increasing in Al2O3 content. Meanwhile, the higher CaO content increased the catalyst reducibility and also the concentration of basic sites. The sample with Al/Ca of 2 had the best performance with glycerol conversion of 99.4% and H2 yield of 99.9% at 700 °C. Moreover, the results revealed that the catalyst calcined at 500 °C, and reduced at 700 °C possessed a glycerol conversion of 99.4% and this catalyst was selected as the best sample among the studied catalysts. [ABSTRACT FROM AUTHOR]