Production of Hydrogen by Steam Reforming of Bio-Ethanol Over Nickel Catalysts Supported on Ceria Based Mixed Oxides

Steam reforming of bio-ethanol is an important process to produce hydrogen, a potential fuel from renewable sources. This manuscript compares the performance of CeO2-Y2O3 and CeO2-Gd2O3 supported NiO catalysts at various reforming temperatures, space velocities and steam to carbon ratios. All the catalysts were prepared through co-precipitation with NiO contents of 10, 15 and 25 wt%. These were characterized by X-ray diffraction (XRD), specific BET surface area, temperature programmed reduction, EDAX analysis. BET surface area has increased initially with NiO loading upto a loading of 15% while it has reduced at higher loading. XRD analysis shows that both CeO2-Y2O3 and CeO2-Gd2O3 were obtained as solid solutions, while there was no indication of NiO forming solid solution. A small reduction in lattice parameter was observed for CeO2-Y2O3 apparently as a result of oxygen ion vacancies while a small but perceptible increase was observed for CeO2-Gd2O3 solid solution. TPR profile shows the presence of Ni2O3 along with NiO. Steam reforming of ethanol shows that the conversion of ethanol reaches 100% even at lower temperatures, but useful conversion calculated in terms of higher hydrogen yield was achieved only at temperatures higher than 823 K. Though higher ethanol conversion was achieved at lower temperatures on yttria based catalysts, useful conversion was similar to that of gadolonia based catalysts mostly as a result of higher methane production on the former.