Segregation of boron and its reaction with oxygen on Rh

János Kiss, Károly Révész, Frigyes Solymosi

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21 Citations (Scopus)

Abstract

The segregation of boron and its reactivity towards oxygen has been investigated by means of AES, XPS, UPS and ELS (in the electronic range) in the temperature range 100-1300 K. The segregation of boron in a Rh foil started from 700 K. The segregated boron produced a peak in XPS for the B(1s) level at 187.8 eV and emissions in UPS at 4.0 and 8.6-9.0 eV for B(2p) and B(2sp2), respectively. Analysis of the results suggested that the segregated boron on Rh foil mainly forms dimers or islands, instead of isolated monomers, without any significant charge transfer between rhodium and boron. Upon oxygen adsorption the B(1s) and O(1s) levels shifted to higher binding energy (to 191.5 and 532.6 eV, respectively) and a new loss in the EELS was produced at 9.4 eV, demonstrating a strong chemical interaction between oxygen and boron. The interaction occurs at as low as 159 K, as indicated by the development of the 9.4 eV loss feature. It is assumed that boron suboxides are formed in which the BB bond is retained. The cleavage of the BB bonds starts above 400 K and is completed at 750 K, when the 2sp2 hybrid state at 8.6-9.0 eV in the UPS, due to the BB bond, is no longer detected. Formation of a polymer-like B2O3 species is proposed which reacts with elemental boron above 900 K to give B2O2.

Original languageEnglish
Pages (from-to)95-110
Number of pages16
JournalApplied Surface Science
Volume37
Issue number1
DOIs
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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