Chemical Engineering Journal, Vol.292, 321-325, 2016
Unsteady-state operation of supported platinum catalysts for high conversion of methane
Total oxidation of methane over model monolith catalysts with platinum supported on alumina, alumina-ceria and ceria has been studied under unsteady-state operation of the feed gas stoichiometry. The general activity for methane oxidation follows the order Pt/alumina < Pt/alumina-ceria < Pt/ceria. Thanks to high catalytic activity at the gas composition switches, increased cycling frequency between oxygen excess and oxygen free conditions increases the average methane conversion significantly from 11% to 58% for Pt/alumina and from 25% to 87% for Pt/alumina-ceria. The corresponding stationary methane conversion is 10% and 19%, respectively. The underlying reason for the enhanced catalytic activity is likely twofold namely that periods with detrimentally high coverage of either oxygen or carbon are shortened and that the transients induce a highly active (chemical) state of the catalyst, thus, facilitating high average conversion of methane. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Transient reactor operation;Enhanced catalyst efficiency;Oxygen self-poisoning;Methane activation