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| 3. |
- Skoglundh, Magnus, 1965, et al.
(author)
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Improved light-off performance by using transient gas compositions in the catalytic treatment of car exhausts
- 1999
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In: Chemical Engineering Science. - 0009-2509. ; 54:20, s. 4559-4566
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Journal article (peer-reviewed)abstract
- The influence of transient changes in the exhaust gas composition on the low-temperature activity of a Pt/CoOx/Al2O3, catalyst and a commercial three-way catalyst has been studied. Periodic O2 and CO pulses caused well-controlled perturbations in the composition of a synthetic car exhaust which was found to affect the overall performance of both catalysts. The presence of transients shifted the conversion starts of CO and propene as well as their light-off temperatures towards lower temperatures. The improved performance is suggested to origin from the combined effect of rich (CO) and lean (O2) pulses that cause perturbations in the adsorbate composition on the active sites at temperatures below light-off.
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- Skoglundh, Magnus, 1965, et al.
(author)
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Light-off performance over cobalt oxide- and ceria-promoted platinum and palladium catalysts
- 1998
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In: Studies in Surface Science and Catalysis. - 0167-2991. ; 116, s. 113-122
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Journal article (peer-reviewed)abstract
- Monolith catalysts containing Co, Ce, Pt and Pd supported on alumina were prepared and tested with respect to low-temperature activity for oxidation of CO and propene. The catalysts were either pre-oxidised or pre-reduced prior to evaluation with respect to light-off performance, using net oxidising and net reducing CO/C3H6/O2/N2 gas mixtures. Promotion of Pt and Pd with cobalt or cerium oxide, favoured the low temperature activity significantly. Pre-reduction of Co- and Ce-promoted noble metals shifted the conversion starts of CO and propene toward lower temperatures compared with pre-oxidised samples. Pre-reduction of cobalt oxide, without Pt or Pd, yielded a dramatic improvement of the low-temperature catalytic performance compared with pre-oxidation of the said oxide. The catalysts were characterised by temperature programmed desorption of CO and specific surface area measurements. The high activity over the pre-reduced cobalt containing catalysts is suggested to be due to the presence of reduced cobalt oxide sites on those samples.
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| 7. |
- Thormählen, Peter, 1969, et al.
(author)
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Catalytic oxidation of CO in cold start emissions
- 1998
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In: 2nd World Congress on Environmental Catalysis as part of Topical Conference on Environmental Catalysis and Reaction Engineering in Miami Beach, Florida, USA, November 15-20, 1998..
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Conference paper (peer-reviewed)
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| 10. |
- Thormählen, Peter, 1969, et al.
(author)
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Low temperature CO oxidation over platinum and cobalt oxide catalysts
- 1999
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In: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 188:2, s. 300-310
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Journal article (peer-reviewed)abstract
- The low-temperature CO oxidation activity of three monolith catalysts (Pt/Al2O3, CoOx/Al2O3, and Pt/CoOx/Al2O3) has been studied. The catalytic properties of the catalysts were investigated by using different temperature-programmed methods: CO-TPD (desorption), TPO (oxidation), TPR (reduction), TPReaction, and CO light-off. Preoxidized cobalt-oxide-containing catalysts were found to be highly active for CO oxidation at temperatures as low as 200 K,and at these low temperatures the activity is independent of the presence of platinum. The catalytic properties and how they relate to the surface reaction kinetics are discussed.
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