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FältnamnIndikatorerMetadata
00004324naa a2200529 4500
001oai:research.chalmers.se:a01374fa-453d-425d-813b-cbb6a7990ba3
003SwePub
008171007s2004 | |||||||||||000 ||eng|
009oai:DiVA.org:uu-235921
0247 a https://research.chalmers.se/publication/83312 URI
0247 a https://doi.org/10.1016/j.jcat.2004.06.0092 DOI
0247 a https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-2359212 URI
040 a (SwePub)cthd (SwePub)uu
041 a engb eng
042 9 SwePub
072 7a art2 swepub-publicationtype
072 7a ref2 swepub-contenttype
1001 a Carlsson, Per-Anders,d 1972u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)perc
2451 0a A transient in situ FTIR and XANES study of CO oxidation over Pt/Al2O3 catalysts
264 1b Elsevier BV,c 2004
520 a We report experimental results for the oxidation of CO over supported Pt/Al2O3 catalysts operating in oxygen excess at atmospheric pressure. To study the reaction kinetics under transient conditions we have employed step changes of the O2 concentration by intermittently switching off the O2 supply at various temperatures ranging from 523 to 623 K. Detailed in situ FTIR and XANES data for CO coverage and the chemical state of Pt, respectively, are presented together with the CO conversion, which in both cases was monitored by mass spectrometry. A red-shift of the vibrational frequency of linearly bonded CO which correlates with a blue-shift of the Pt LIII binding energy indicates that the Pt catalyst initially is partially oxidised and gradually reduced when the O2 supply is switched off. Control experiments with a NO2 oxidised Pt/Al2O3 catalyst support these findings. A hysteresis in the catalytic activity due to the different rates whereby Pt is oxidised and reduced as a function of gas-phase composition is observed. The activation energy for the Pt oxide reduction (decomposition) process is estimated to be about 50 kJ/mol. The results further emphasise that the conventional three-step Langmuir-Hinshelwood (LH) scheme used to interpret CO oxidation on Pt surfaces must be complemented by a Pt oxidation and reduction mechanism during transient conditions. Moreover, FTIR data suggest that during the extinction, the partially oxidised platinum surface is reduced by chemisorbed CO which should be explicitly accounted for in the modeling of the reaction mechanism.
650 7a NATURVETENSKAPx Fysik0 (SwePub)1032 hsv//swe
650 7a NATURAL SCIENCESx Physical Sciences0 (SwePub)1032 hsv//eng
650 7a NATURVETENSKAPx Geovetenskap och miljövetenskapx Miljövetenskap0 (SwePub)105022 hsv//swe
650 7a NATURAL SCIENCESx Earth and Related Environmental Sciencesx Environmental Sciences0 (SwePub)105022 hsv//eng
653 a Ignition
653 a Platinum
653 a Step-response experiments
653 a Pt/Al<sub>2</sub>O<sub>3</sub>
653 a XANES
653 a FTIR
653 a Catalysis
653 a CO oxidation
653 a Extinction
653 a Platinum oxide
7001 a Österlund, Lars,d 1967u Uppsala universitet,Fasta tillståndets fysik4 aut0 (Swepub:uu)laros288
7001 a Thormählen, Peter,d 1969u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)petert
7001 a Palmqvist, Anders,d 1966u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)adde
7001 a Fridell, Erik,d 1963u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)fridell
7001 a Jansson, Jonas,d 1973u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)jansson
7001 a Skoglundh, Magnus,d 1965u Chalmers tekniska högskola,Chalmers University of Technology4 aut0 (Swepub:cth)skoglund
7102 a Chalmers tekniska högskolab Chalmers University of Technology4 org
7730 t Journal of Catalysisd : Elsevier BVg 226:2, s. 422-434q 226:2<422-434x 0021-9517x 1090-2694
8564 u http://dx.doi.org/10.1016/j.jcat.2004.06.009y FULLTEXT
8564 8u https://research.chalmers.se/publication/8331
8564 8u https://doi.org/10.1016/j.jcat.2004.06.009
8564 8u https://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-235921

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