Study On Hydrogen Production By Ethanol Steam Reforming Over Pd/Al₂O₃ Catalyst

The utilizations of hydrogen attract much attention all over the world due to the rapid development of fuel cell technique. Producing hydrogen from ethanol steam reforming would be environmentally friendly. Hydrogen production by ethanol steam reforming over Pd-based catalyst was evaluated. The influence of Pd loading and reactor temperature of the Pd/Al₂O₃ catalyst performance was mainly studied.The products of ethanol steam reforming were analyzed. Acetaldehyde, acetone, carbon monoxide, carbon dioxide, methane, ethane and ethylene were separated and qualitatively analyzed, respectively. The reaction mechanism was concluded.The dependence of the catalytic activity and selectivity on reaction temperature, Pd loading with Al₂O₃ was studied. Hydrogen selectivity was proportional to the high Pd loading or high reactor temperature and ethanol was completely converted even at relatively high temperature values. Hydrogen selectivities up to 110% were obtained at temperature values close to 750℃with 1wt%Pd/Al₂O₃ catalyst. And Hydrogen selectivities up to maximum value (134%) were obtained at 5wt%Pd/Al₂O₃ at 650℃reactor temperature.The effect of Pd over the different supported solid oxide catalysts on the reaction activity was investigated. The evaluation results showed that there was a significant increasing on the catalyst activity when ZrO₂ was used. However,ethylene was effectively restrained by Pd/Ce₂O₃ catalyst.The characteristic analysis by XRD , XPS, TGA and NH₃-TPD showed that the nature of Pd0 catalyst relatively stabilized. However, Pd metallic clusters were formed after reaction. Carbon rate formation and acidic sites on the catalyst surface was decreased by increasing Pd loading and reactor temperature.