Heat treatment driven surface segregation in Pd77Ag23 membranes and the effect on hydrogen permeability

Tianmiao Lai, Marylaura Thomas

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We applied different heat treatment to commercial Pd77Ag23 membranes to promote surface segregation and measured the influence of surface segregation on hydrogen permeability. We report X-ray photoelectron spectroscopy (XPS) analysis of the surface elemental composition of the membranes. We used atomic force microscopy (AFM) to observe the surface roughness and area change. We found that surface composition varied with the method of heat treatment. The surface area of all membranes increased after heat treatment. We found that the higher the surface Pd/(Pd + Ag) ratio, the higher the hydrogen permeability. We demonstrate that surface carbon removal and surface area increase do not explain the observed permeability differences. The vacuum level during the heat treatment is crucial to promote Ag surface segregation of membranes. After exposure to hydrogen, we observed reverse segregation (Pd segregation).

Original languageEnglish (US)
Pages (from-to)373-382
Number of pages10
JournalInternational Journal of Hydrogen Energy
Volume40
Issue number1
DOIs
StatePublished - Jan 5 2015

Keywords

  • Heat treatment
  • Hydrogen permeability
  • PdAg
  • Surface roughness
  • Surface segregation

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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