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Title: Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

An ultra-high vacuum (UHV) setup for “real” and “inverse” model catalyst preparation, depth-resolved near-surface spectroscopic characterization, and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the all-quartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile, and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy, and low-energy ion scattering measurements. Due the dedicated geometry of the X-ray gun (54.7°, “magic angle”) and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depths, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained. To demonstrate the capability ofmore » the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming on PdGa and PdZn near-surface intermetallic phases are shown.« less
Authors:
; ;  [1] ;  [1] ;  [2] ;  [1] ;  [3]
  1. Institute of Physical Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck (Austria)
  2. (Germany)
  3. (Austria)
Publication Date:
OSTI Identifier:
22254894
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; AUGER ELECTRON SPECTROSCOPY; CATALYSIS; CATALYSTS; DESIGN; ELECTRON BEAMS; EVAPORATORS; METHANOL; MICROBALANCES; PUMPS; QUARTZ; REACTION KINETICS; SAMPLE HOLDERS; SAMPLE PREPARATION; THICKNESS; X RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY