Pt-implanted intermetallides as the catalysts for CH4-CO2 reforming

A new type of catalytic system on the base of Ni3Al intermetallic compound was proposed for CO2 reforming of methane. Several catalysts were prepared by self-propagating high temperature synthesis and characterized by XRD (in situ and ex situ), DTA-TG, SEM + EDS, HRTEM + EDS and XPS. Ion implantation was used as a method of catalyst surface modification. Activity testing has been performed in the fixed bed reactor at the temperatures of 600-900 degrees C under atmospheric pressure and the reactant molar ratio of 1. The structure and morphology of different types of carbon deposits obtained on the surface of unmodified Ni3Al were investigated. The results indicated that the addition of a low amount (less than 0.1 wt%) of Pt to the Ni3Al intermetallide leads to a decrease in carbon deposition and Pt-implanted catalysts were stable for a long period of time. The evidence suggests that the differences in the stabilities may be due to the following reasons: (1) Pt prevents Ni phase sintering by avoiding particle coalescence, which is the main sintering process under severe CH4-CO2 reforming conditions, (2) Pt hinders deactivating carbon formation by limiting bulk nickel carbide and therefore carbon filament formation, which may lead to reactor plugging and/or particle fragmentation, and by suppressing encapsulating carbon formation which limits access of reactant to the active nickel phase. (C) 2011 Elsevier B. V. All rights reserved.