Carbon deposition and gasification kinetics of used lanthanide-promoted Co-Ni/Al2O3 catalysts from CH4 dry reforming

The kinetics of both carbon deposition and removal on lanthanide-promoted Co-Ni/Al2O3 dry reforming catalysts were investigated. Carbon deposition rate decreased with temperature in the range, 923-1023 K. Catalyst regeneration (via TPR-TPO-TPR and TPO-TPR) may be adequately modelled by the geometrical contracting volume gas-solid reaction model. Lanthanide promotion resulted in lower coke formation due to interaction of the rare-earth oxide with the more reactive surface carbonaceous matter in redox reactions, while the amount of the less reactive deposited carbon pool remained similar in all catalysts. Although both regeneration schemes studied were able to completely remove all carbon, samples from the TPO-TPR regime experienced marginal sintering. (C) 2012 Elsevier B.V. All rights reserved.