AIP Advances (Jan 2019)

Operando study of Pd(100) surface during CO oxidation using ambient pressure x-ray photoemission spectroscopy

  • Youngseok Yu,
  • Dongwoo Kim,
  • Hojoon Lim,
  • Geonhwa Kim,
  • Yoobin E. Koh,
  • Daehyun Kim,
  • Kohei Ueda,
  • Satoru Hiwasa,
  • Kazuhiko Mase,
  • Fabrice Bournel,
  • Jean-Jacques Gallet,
  • François Rochet,
  • Ethan J. Crumlin,
  • Philip N. Ross Jr.,
  • Hiroshi Kondoh,
  • Do Young Noh,
  • Bongjin Simon Mun

DOI
https://doi.org/10.1063/1.5081066
Journal volume & issue
Vol. 9, no. 1
pp. 015314 – 015314-8

Abstract

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The surface chemical states of Pd(100) during CO oxidation were investigated using ambient pressure x-ray photoelectron spectroscopy and mass spectroscopy. Under the reactant ratio of CO/O2 = 0.1, i.e. an oxygen-rich reaction condition, the formation of surface oxides was observed with the onset of CO oxidation reaction at T = 525 K. As the reactant ratio (CO/O2) increased from 0.1 to 1.0, ∼ 90 % surface oxides remains on surface during the reaction. Upon the formation of surface oxides, the core level shift of oxygen gas phase peak was observed, indicating that change of surface work function. As CO oxidation takes places, i.e. making a transition from CO covered surface to the oxidic surface, the work functions of surface oxide on Pd(100) and Pt(110) display opposite behavior.