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Title: Closing the pressure gap in x-ray photoelectron spectroscopy by membrane hydrogenation

Comprehensive studies of gas-solid reactions require the in-situ interaction of the gas at a pressure beyond the operating pressure of ultrahigh vacuum (UHV) X-ray photoelectron spectroscopy (XPS). The recent progress of near ambient pressure XPS allows to dose gases to the sample up to a pressure of 20 mbar. The present work describes an alternative to this experimental challenge, with a focus on H{sub 2} as the interacting gas. Instead of exposing the sample under investigation to gaseous hydrogen, the sample is in contact with a hydrogen permeation membrane, through which hydrogen is transported from the outside to the sample as atomic hydrogen. Thereby, we can reach local hydrogen concentrations at the sample inside an UHV chamber, which is equipped with surface science tools, and this corresponds to a hydrogen pressure up to 1 bar without affecting the sensitivity or energy resolution of the spectrometer. This experimental approach is validated by two examples, that is, the reduction of a catalyst precursor for CO{sub 2} hydrogenation and the hydrogenation of a water reduction catalyst for photocatalytic H{sub 2} production, but it opens the possibility of the new in situ characterisation of energy materials and catalysts.
Authors:
;  [1] ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [1]
  1. Laboratory for Advanced Analytical Technologies, Swiss Federal Laboratories for Materials Science and Technology (Empa), Überlandstrasse 129, CH-8600 Dübendorf (Switzerland)
  2. (Empa), Überlandstrasse 129, CH-8600 Dübendorf (Switzerland)
  3. Department of Chemistry, University of Zürich (UZH), CH-8057 Zürich (Switzerland)
  4. Laboratory for Hydrogen and Energy, Swiss Federal Laboratories for Materials Science and Technology (Empa), Überlandstrasse 129, CH-8600 Dübendorf (Switzerland)
  5. (EPFL), SB, ISIC, LMER, CH-1015 Lausanne (Switzerland)
Publication Date:
OSTI Identifier:
22392489
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 5; Other Information: (c) 2015 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; CARBON DIOXIDE; CATALYSTS; ENERGY RESOLUTION; GASES; HYDROGEN; HYDROGENATION; MEMBRANES; PHOTOCATALYSIS; SPECTROMETERS; X-RAY PHOTOELECTRON SPECTROSCOPY