Steam reforming of toluene, methane and mixtures over Ni/ZrO2 catalysts

This work studied the performance of Ni catalysts supported on three different zirconia structures for SR of toluene, methane and methane/toluene mixtures. The presence of both reactants in the feed decreased the conversion of toluene and methane. This was due to the increase in the concentration of CH. species on the surface of the metallic particle. All Ni/ZrO2 catalysts deactivated during SR of toluene, methane or the mixture. Scanning electron microscopy and thermogravimetric analysis revealed the formation of carbon deposits over the surface of catalysts. However, the amount of carbon deposited depended on the reaction conditions and the structure of zirconia. Monoclinic zirconia exhibits a lower densitiy of acid sites and a higher degree of hydration, which contributes to the lower carbon formation. The amount of carbon deposited over all catalysts significantly increased during SR of the mixture. This is due to a decrease in the rate of the gasification reaction and an increase in the rate of the CH. species formation reaction, which enhances the catalysts deactivation rate. (C) 2016 Elsevier B.V. All rights reserved.