Pd segregation to the surface of Au on Pd(111) and on Pd/TiO2(110)

Ryan Sharpe, Jon Counsell, Michael Bowker

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The interaction of Au and Pd in bimetallic systems is important in a number of areas of technology, especially catalysis. In order to investigate the segregation behaviour in such systems, the interaction of Pd and Au was investigated by surface science methods. In two separate sets of experiments, Au was deposited onto a Pd(111) single crystal, and Pd and Au were sequentially deposited onto TiO2(110), all in ultra-high vacuum using metal vapour deposition. Heating Au on Pd/TiO2(110) to 773 K resulted in the loss of the Au signal in the LEIS, whilst still remaining present in the XPS, due to segregation of Pd to the surface and the formation of a Au-Pd core-shell structure. It is likely that this is due to alloying of Au with the Pd and surface dominance of that alloy by Pd. The Au:Pd XPS peak area ratio is found to substantially decrease on annealing Au/Pd(111) above 773 K, corresponding with a large increase in the CO sticking probability to that for clean Pd(111). This further indicates that Au diffuses into the bulk of Pd on annealing to temperatures above 773 K. It therefore appears that Au prefers to be in the bulk in these systems, reflecting the exothermicity of alloy formation.

Original languageEnglish
Pages (from-to)60-65
Number of pages6
JournalSurface Science
Volume656
DOIs
Publication statusPublished - 1 Feb 2017

Keywords

  • Au-Pd alloys
  • Core-shell
  • Model catalysts
  • Nanoparticles
  • Pd(111)
  • TiO(110)

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Pd segregation to the surface of Au on Pd(111) and on Pd/TiO2(110). / Sharpe, Ryan; Counsell, Jon; Bowker, Michael.

In: Surface Science, Vol. 656, 01.02.2017, p. 60-65.

Research output: Contribution to journalArticle

Sharpe, Ryan ; Counsell, Jon ; Bowker, Michael. / Pd segregation to the surface of Au on Pd(111) and on Pd/TiO2(110). In: Surface Science. 2017 ; Vol. 656. pp. 60-65.
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