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Induced low temperature catalytic ignition by transient changes in the gas composition |
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| Authors: | Per-Anders Carlsson Magnus Skoglundh Erik Fridell Edward Jobson and Bengt Andersson |
| Affiliation: | a Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96 Göteborg, Sweden b Department of Chemical Reaction Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden c Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden d Department of Applied Surface Chemistry, Chalmers University of Technology, SE-412 96 Göteborg, Sweden e Volvo Technological Development, SE-405 08 Göteborg, Sweden |
| Abstract: | The effect of gas composition changes on the low temperature activity for supported platinum model catalysts has been studied. By introducing well-controlled periodic O2 pulses to a simple diluted gas mixture of CO and O2, a substantial improvement of the low temperature oxidation activity was observed. The reason for low activity on noble metals at low temperatures is often attributed to self-poisoning by CO. The improved catalytic performance observed is proposed to origin from the transients causing a surface reactant composition that is favourable for the reaction rate, i.e. lower degree of self-poisoning. This was also confirmed by in situ Fourier transform infrared (FT-IR) spectroscopy in combination with mass spectrometry (MS) measurements, which gave evidence for the existence of a strong interplay between the gas phase concentration and the adsorbate composition for these catalysts. |
| Keywords: | Platinum Carbon monoxide Catalytic oxidation Low temperature activity Self-poisoning Cold start emissions Periodic pulsing Transient changes In situ FT-IR DRIFT |
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