Oxygen adsorption on nickel surfaces: Detection of different species by x-ray photoelectron spectroscopy

✍ Scribed by C.R. Brundle; A.F. Carley

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 525 KB
• Volume: 31
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(75)85056-1

✦ Synopsis

Interaction of oxygen with evaporated nickel films has been studied by v ~-ray photoelectron spectrosmpy. XPS, over the temperature nnge 77-500 K and pressure range 10mg -IO4 torr. Three oxygen species Iiave been- positively,identified from O(ls) bir.ding energy shifts (I, II and III with BE's 5295.531.4 and 533.2 eV). A fourth state at u. 534.8 eV may also exist. The rehtive proportions of each species present depends on the temperature of the substrate. Type I is tentatively considered to represent oxygen atoms in an oxide-like electronic environmeat~ type 11 is assigned as chemisorbed oxygen atoms, &ho&_ the possibility of assignment at high oxygen mi'cnges ?o a defect Ni203 structure is admitted. Type III is only formed in sub-,xonolayer quaniities on interaction at 7'/ K; converting irreversibly to II on warming to 300 K. I and II me elways formed together between 300 and 500 K. The auihors believe this implies some incorporation of oxygen atoms from the start of adsorption, which in turT hu important implications for recent LEED studies.