Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating

Renaud Delmelle, Peter Ngene, Bernard Dam, Davide Bleiner, Andreas Borgschulte

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

The catalytic activity of Pd surfaces towards hydrogen desorption was significantly improved by a nanometer-thin polytetrafluoroethylene (PTFE) layer, as shown by an enhancement in the permeability of a Pd membrane coated on the permeate side. The origin of this effect was found to be due to a lowering of the barrier for hydrogen desorption, as evidenced by a change in the rate-limiting mechanism of hydrogen permeation through the membrane from desorption (un-coated) to diffusion controlled. In situ X-ray photoelectron spectroscopy (XPS) revealed the electronic structure of the sputtered PTFE. Apart from C-Fn subunits (n=1, 2, 3), we found that nonsaturated carbon atoms became hydrogenated during hydrogen permeation, which was indicative of an interaction between Pd and PTFE. This interaction was weak; no Pd-F bonds were formed. We thus attributed the effect to an increase in the hydrophobicity of the surface by the porous PTFE layer and to a promoter effect of hydrogen desorption as a result of electrostatic interactions between chemisorbed hydrogen and physisorbed PTFE.

Original languageEnglish
Pages (from-to)1646-1650
Number of pages5
JournalChemCatChem
Volume8
Issue number9
DOIs
Publication statusPublished - 9 May 2016

Keywords

  • electrostatic interactions
  • hydrogen desorption
  • membranes
  • palladium
  • polymer coatings

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