title: Silicon drift detectors as a tool for time-resolved fluorescence XAFS on low-concentrated samples in catalysis.
abstract: A silicon drift detector (SDD) was used for ex situ and time-resolved in situ fluorescence X-ray absorption fine structure (XAFS) on low-concentrated catalyst samples. For a single-element and a seven-element SDD the energy resolution and the peak-to-background ratio were verified at high count rates, sufficient for fluorescence XAFS. An experimental set-up including the seven-element SDD without any cooling and an in situ cell with gas supply and on-line gas analysis was developed. With this set-up the reduction and oxidation of a zeolite supported catalyst containing 0.3 wt% platinum was followed by fluorescence near-edge scans with a time resolution of 10 min each. From ex situ experiments on low-concentrated platinum- and gold-based catalysts fluorescence XAFS scans could be obtained with sufficient statistical quality for a quantitative analysis. Structural information on the gold and platinum particles could be extracted by both the Fourier transforms and the near-edge region of the XAFS spectra. Moreover, it was found that with the seven-element SDD concentrations of the element of interest as low as 100 ppm can be examined by fluorescence XAFS.
authors.affiliation: Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, Hamburg, Germany. peter.kappen@desy.de
authors.forename: Peter
authors.initials: P
authors.lastname: Kappen
authors.forename: Larc
authors.initials: L
authors.lastname: Tröger
authors.forename: Gerhard
authors.initials: G
authors.lastname: Materlik
authors.forename: Christian
authors.initials: C
authors.lastname: Reckleben
authors.forename: Karsten
authors.initials: K
authors.lastname: Hansen
authors.forename: Jan-Dierk
authors.initials: JD
authors.lastname: Grunwaldt
authors.forename: Bjerne S
authors.initials: BS
authors.lastname: Clausen