Sy. Li et al., REACTION OF HYDROGEN WITH O RU(001) AND RUOX FILMS - FORMATION OF HYDROXYL AND WATER/, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 15(3), 1997, pp. 1692-1697
Citations number
24
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
The interaction of gas phase atomic hydrogen with chemisorbed oxygen o
n Ru(001) and RuOx films has been investigated by means of Auger elect
ron spectroscopy and thermal desorption spectroscopy at surface temper
atures between 120 and 320 K. Although molecular hydrogen does not ads
orb on oxygen saturated Ru(001) or RuOx films even at 120 K, atomic hy
drogen reacts with oxygen on Ru(001) surfaces, and both D-2 and D2O de
sorb at temperatures below 500 g. The 2D(gas)+O-ad->D2Ogas reaction is
approximately six times faster at 310 K than at 120 K. For RuOx films
, a unity reaction probability was found at oxygen coverages above 3 m
onolayers (ML), while it decreased to 0.4 at theta(0) < 3 ML. Such var
iation can be attributed to a change in the structure of the oxide fil
m. The reaction probably follows an Eley-Rideal mechanism where gas ph
ase atomic hydrogen reacts with oxygen prior to thermal accommodation
within the surface. The desorption of water is the rate limiting step
at surface temperatures below 200 K, whereas the formation of water is
the rate limiting step at higher temperatures. (C) 1997 American Vacu
um Society.