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The effect of plati...
The effect of platinum distribution in monolithic catalysts on the oxidation of CO and hydrocarbons
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- Arnby, Karl, 1974 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Assiks, Johan, 1979 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Carlsson, Per-Anders, 1972 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Palmqvist, Anders, 1966 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Skoglundh, Magnus, 1965 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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(creator_code:org_t)
- Elsevier BV, 2005
- 2005
- Engelska.
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Ingår i: Journal of Catalysis. - : Elsevier BV. - 0021-9517 .- 1090-2694. ; 233:1, s. 176-185
- Relaterad länk:
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http://dx.doi.org/10...
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https://research.cha...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Monolithic Pt/gamma-Al2O3 catalysts were prepd. by depositing of the platinum phase, either homogeneously or heterogeneously (i.e., local high platinum concn.), in the washcoat. The influence of the platinum distribution on the ignition and extinction processes for oxidn. of CO, propene, and propane, resp., was investigated by both temp.-programmed and oxygen step-response flow-reactor expts. In addn., in situ XANES spectroscopy was used to follow changes in the chem. state of platinum during propane oxidn. For samples with heterogeneous platinum distribution, the results show an improved low-temp. activity for CO oxidn., whereas no clear improvement is obsd. for oxidn. of propene or propane. Comparison of the results for CO and hydrocarbon oxidn. shows that the improved activity cannot be explained by thermal effects. Moreover, calcns. indicate that the enhanced activity for CO oxidn. can be due to mass-transfer phenomena. This could not be confirmed by our expts., however. Instead, the improved activity for CO oxidn. can be due to varying platinum particle size between the samples. Furthermore, the oxidn. of propane is shown to be highly influenced by the oxygen concn., showing an activity max. for gas compositions close to the stoichiometric. High oxygen levels result most probably in a predominantly oxygen-covered surface, which inhibits the reaction and, as supported by the in situ XANES experiments, passivates the surface by forming platinum oxide.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Kemiteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Chemical Engineering (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)
Nyckelord
- Platinum
- Mass transport
- Alumina
- Environmental catalysis
- Propane
- Structure sensitivity
- XANES spectroscopy
- Total oxidation
- Heat transport
- CO
- Propene
- Low-temperature activity
- Platinum oxide
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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