| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 145693 | Chemical Engineering Journal | 2016 | 5 Pages |
•Unsteady-state operation enhances catalytic processes.•Promoting methane oxidation by transient operation.•Utilisation of temporary states with high catalytic activity.
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.
