Affordable Access

Publisher Website

Oxidation of Pt(1 0 0)-hex-R0.7° by gas-phase oxygen atoms

Surface Science
Publication Date
DOI: 10.1016/j.susc.2006.09.040
  • Oxidation
  • Platinum
  • Atomic Oxygen
  • Atom-Solid Interactions
  • Desorption
  • Single Crystal Surfaces
  • Metal-Oxide Interfaces
  • Physics


Abstract We utilized temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (ELS), and low energy electron diffraction (LEED) to investigate the oxidation of Pt(1 0 0)-hex-R0.7° at 450 K. Using an oxygen atom beam, we generated atomic oxygen coverages as high as 3.6 ML (monolayers) on Pt(1 0 0) in ultrahigh vacuum (UHV), almost 6 times the maximum coverage obtainable by dissociatively adsorbing O 2. The results show that oxidation occurs through the development of several chemisorbed phases prior to oxide growth above about 1 ML. A weakly bound oxygen state that populates as the coverage increases from approximately 0.50 ML to 1 ML appears to serve as a necessary precursor to Pt oxide growth. We find that increasing the coverage above about 1 ML causes Pt oxide particle growth and significant surface disordering. Decomposition of the Pt oxide particles produces explosive O 2 desorption characterized by a shift of the primary TPD feature to higher temperatures and a dramatic increase in the maximum desorption rate with increasing coverage. Based on thermodynamic considerations, we show that the thermal stability of the surface Pt oxide on Pt single crystal surfaces significantly exceeds that of bulk PtO 2. Furthermore, we attribute the high stability and the acceleratory decomposition rates of the surface oxide to large kinetic barriers that must be overcome during oxide formation and decomposition. Lastly, we present evidence that structurally similar oxides develop on both Pt(1 1 1) and Pt(1 0 0), therefore concluding that the properties of the surface Pt oxide are largely insensitive to the initial structure of the Pt single crystal surface.

There are no comments yet on this publication. Be the first to share your thoughts.


Seen <100 times

More articles like this

An examination of electrochemical and gas phase de...

on Journal of Electroanalytical C... Jan 01, 2003

Hydrogen oxidation at the Pt-BaZr0.1Ce0.7Y0.1Yb0.1...

on Physical Chemistry Chemical Ph... Mar 21, 2013
More articles like this..