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The potential of operando XAFS for determining the role and structure of noble metal additives in metal oxide based gas sensors

Grunwaldt, J.-D.; Hübner, M.; Koziej, D.; Barsan, N.; Weimar, U.

Abstract:
Noble metal additives significantly improve the performance of SnO2 based sensors. Recently, it has been found that X-ray absorption spectroscopy is an excellent tool to identify their structure under sensing conditions, despite of the low concentrations and the rather thin (50 μm) and highly porous layers. For this purpose a new in situ approach has been established and here we highlight the potential with an overview on the results of Pd-, Pt-, and Au-additives in SnO2-based sensors at work. Emphasis was laid on recording the structure (by XANES and EXAFS) and performance at the same time. In contrast to earlier studies, Pd- and Pt-additives were observed to be in oxidized and finely dispersed state under sensing conditions excluding a spillover from metallic noble metal particles. However, Au was mainly present as metallic particles in the sensing SnO2-layer. For the Pt- and Au-doped SnO2-layers high energy-resolved fluorescence detected X-ray absorption spectra (HERFD-XAS) were recorded not only to minimize the lifetime-broadening but also to eliminate the Au- and Pt-fluorescence effectively and to record range-extended EXAFS.

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Verlagsausgabe §
DOI: 10.5445/IR/1000047580
Veröffentlicht am 28.05.2018
Originalveröffentlichung
DOI: 10.1088/1742-6596/430/1/012078
Scopus
Zitationen: 6
Coverbild
Zugehörige Institution(en) am KIT Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2013
Sprache Englisch
Identifikator ISSN: 1742-6588, 1742-6596
urn:nbn:de:swb:90-475802
KITopen-ID: 1000047580
Erschienen in Journal of physics / Conference Series
Band 430
Heft 1
Seiten 012078
Nachgewiesen in Scopus
Web of Science
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