Characterization of alumina-supported Ni and Ni-Pd catalysts for partial oxidation and steam reforming of hydrocarbons

Hydrogen production by partial oxidation and steam reforming (POSR) of n-octane has been investigated over alumina-supported Ni and Ni-Pd catalysts. The process was found to occur by a combination of exothermic partial oxidation and endothermic steam reforming. Ni/gamma-Al2O3 catalysts had good activity at high temperatures; the activity increased with increasing Ni loadings up to 5.0 wt.%. However, the Ni/gamma-Al2O3 catalysts rapidly lost activity during the POSR process. XRD results showed that an increase in the particle size was the main reason for the poor stability of the Ni/gamma-Al2O3 catalysts. A further important reason was the deposition of carbon produced during the POSR process on the Ni/gamma-Al2O3 catalyst surface. The activity and hydrogen selectivity of Ni-Pd/gamma-Al2O3 catalyst were significantly higher than the values of the nickel catalyst under the same experimental conditions. Catalytic stability was also enhanced by the presence of palladium. Such improvement indicates that palladium plays an important role in the catalytic action. SEM and TG results did not show any great difference between the fresh and spent Ni-Pd/gamma-Al2O3 catalysts. Overall, the bimetallic Ni-Pd/gamma-Al2O3 catalyst could be an effective catalyst for the production of hydrogen from hydrocarbons. (C) 2002 Elsevier Science B.V. All rights reserved