Characterization of NiAl and NiCuAl catalysts prepared by different methods for hydrogen production by thermo catalytic decomposition of methane

NiAl and NiCuAl catalysts have been prepared by co-precipitation, fusion and impregnation methods to promote the Ni formation, as active phase, in different degrees of dispersion and crystal domain sizes as evidenced through the characterization study of fresh catalysts. Performance tests show that the hydrogen production was not highly dependent on the preparation method used but the presence of Cu as a dopant in NiCuAl catalysts enhanced the catalytic activity substantially. The catalyst deactivation was never reached at the fixed times used in the reactivity tests. The Ni properties, mostly derived from thermal sintering and chemical-induced faceting were substantially altered during the process of methane decomposition, and the properties of the deposited carbon were highly dependent on the presence of Cu as a dopant in NiCuAl catalysts. NiCuAl catalysts enhances the formation of a well-ordered graphitic carbon while NiAl catalysts promote the deposition of a turbostratic carbon suitable as catalytic supports or hydrogen storage. (C) 2006 Elsevier B.V. All rights reserved.