Influence of the Urea Content in the Combustion Synthesis for Preparation of NiAl2O4 Support Catalytic to Steam Reforming of Methane

The aim of this work is to evaluate the catalytic performance in steam reforming of methane of the NiAl2O4catalysts prepared by combustion reaction with different urea levels. The catalysts were prepared with urea in the stoichiometric proportion, and with excess of 10% and 20%. The samples were characterized by DRX, textural analysis by nitrogen adsorption, SEM, TPR, and then, catalytically evaluated in the methane reforming reaction. The results showed the presence of NiAl2O4and traces of NiO for all the samples. The increase of the urea content caused an increase in the particle size and a reduction in the surface area, from 171 to 35 m2/g. All the samples presented irregular morphology. The TPR curves showed peaks of reduction of the NiO species, and reduction of nickel present in the NiAl2O4. Regarding the conversion of methane to synthesis gas, it was observed that the increase of the urea content allowed obtaining higher conversion. However, it was also observed a rapid deactivation of these catalysts due to high coke deposition on the active phases surfaces.