Skip to main content
Article thumbnail
Location of Repository

The adsorption and incorporation of oxygen on Cu(100) and its reaction with carbon monoxide; comparison with Cu(111) and Cu(110)

By F.H.P.M. Habraken, C.M.A.M. Mesters and G.A. Bootsma

Abstract

Ellipsometry, LEED, Auger electron spectroscopy and monitoring of work function changes have been used to study the interactions of O2 and N2O with a clean annealed Cu(100) surface and of the reaction of CO with sorbed oxygen. Gas pressures were in the range 10−7−10−4 Torr and crystal temperatures varied between 25–400°C. The initial interaction of oxygen with Cu(100) occurs in three stages. Oxygen chemisorbs with an initial sticking coefficient of ˜10−7 at room temperature and an apparent activation energy of 1.3−3.5 kcal/mol, depending on the substrate temperature. The first stage is the formation of a (√2 × √2)R45° LEED pattern up to a coverage of 0.5, which is converted with an apparent activation energy of 3.2 kcal/mol to a (√2 × 2√2)R45° structure at a coverage of 0.75 in the second stage. The work function increases inthe first stage in an amount of ˜300 meV, but decreases in the second stage to the value of the clean surface. In a third stage after an induction period further oxygen uptake could be registered only with ellipsometry. The apparent activation energy is 4.5 kcal/mol. The initial decomposition probability of N2O at room temperature is 5 × 10−5, its apparent activation energy 3.2 kcal/mol. The LEED patterns observed were the same as with O2. The sorbed oxygen can be removed at all coverages with CO. The reaction appears to follow Langmuir-Hinshelwood kinetics with an activation energy for the reaction COad + Oad → CO2 of 19–20 kcal/mol. A comparison is made with the data obtained for Cu(111) and Cu(110)

Topics: Scheikunde
Year: 1980
OAI identifier: oai:dspace.library.uu.nl:1874/24424
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://dspace.library.uu.nl:80... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.