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- 2016 (12) (entfernen)
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- Zeitschriftenartikel (12)
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- Englisch (12) (entfernen)
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- Mechanochemistry (3)
- Single-shot XAFS (3)
- Time resolution (3)
- Adsorbates (2)
- DRIFTS (2)
- In situ (2)
- Infrared spectroscopy (2)
- Metal phosphonate (2)
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- X-ray absorption spectroscopy (2)
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- CO adsorption (1)
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- Divergent XAFS (1)
- Fluorapatite-gelatin nanocomposites (1)
- Gold Synchrotron XRF (1)
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- Phosphates (1)
- Platinum Wavelength dispersive D2XRF (1)
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- Re-XANES (1)
- Sample changer (1)
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- String metal support interaction (1)
- Strong metal support interaction (1)
- TXRF (1)
- TXRF-XANES (1)
- XANES X-ray absorption near edge structure spectroscopy (1)
- XRD (1)
- Zinc phosphate (1)
- mXRF Micro-X-ray fluorescence spectroscopy (1)
- progressive hepatolenticular degeneration (1)
The adsorption behavior of Platinum nanoparticles was studied for the as-received catalyst (under inert gas), under hydrogen and CO atmosphere using our newly designed in-situ cell. X-ray Absorption Spectroscopy (XAS) and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) experiments were performed simultaneously with high data quality. Structural information and the type of adsorbate could be revealed via Extended X-ray Absorption Fine Structure (EXAFS) analysis, Dl X-ray Absorption Near Edge Structure analysis (Dl XANES) and in-situ DRIFTS. The as-received catalyst showed sub-surface oxygen and O(n-fold). Under CO atmosphere only CO(atop) was found. Reversible adsorbate induced changes of the Pt nanoparticle structure were derived from changes in the PtAPt coordination number and the corresponding bond distance. Under reducing conditions (H2, CO) a significant increase in both values occurred. Temperature dependent desorption of CO revealed a gradual shift from PtACO to PtAO. Reoxidation was clearly assigned to strong metal support interaction from the SiO2 support.
A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved.