Ni catalysts from NiAl2O4 spinel forCO2 reforming of methane

A series of mixed oxides close to NiAl2O4 was obtained by a sol-gel like method (propionic acid). The characterization of the different structures was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) or transmission electron microscopy (TEM). For the stoichiometric ratio of Ni to Al exactly equal to 0.5, homogeneous crystalline spinel phase was formed for a temperature of calcination equal or higher than 725 degrees C. A solid solution was obtained for a Ni/Al ratio lower than 0.5. The spinel structure is non-tolerant concerning a change of nickel to aluminum ratio higher than 0.5: an excess of nickel gives large particles of NiO on spinel phase. Comparative reduction and dry reforming of these oxides was made to control the formation of Ni and its sintering for applications in methane dry reforming. Preliminary reactivity results in dry reforming of methane are given. (c) 2005 Elsevier B.V. All rights reserved.