|
| |
FIZIKA A 4 (1995) 2, 279-286
 
INTERACTION OF OXYGEN AND WATER-VAPOUR WITH CLEAN AND
HYDROGEN-PRECOVERED THIN IRON FILMS STUDIED BY SURFACE POTENTIAL MEASUREMENTS
WOJCIECH LISOWSKI and RYSZARD DU\' S
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224
Warsaw, Poland
Received 7 April 1995
Revised manuscript received 31 May 1995
Oxygen adsorption on both clean and hydrogen-precovered thin Fe films has been
investigated by measuring the surface potential (SP), gas phase composition and the total
gas pressure at 298 K. The results were supplemented by SP studies of water-vapour
adsorption on clean and oxygen-precovered thin iron films. Oxygen interaction with Fe film
pre-exposed to water-vapour has also been studied at 298 K. It has been observed that only
a small part of the initially deposited hydrogen desorbs due to the competitive adsorption
of oxygen. Most of the hydrogen adspecies remain on the surface diminishing the amount of
adsorbed oxygen and affecting the electrical character of the oxygen adsorbate. Water
adsorbs dissociatively on clean Fe film at 298 K, decreasing the SP. Precovering Fe film
with O2 at 298 K prevents the decomposition of water. The amount of oxygen
consumed is only slightly diminished by water preadsorbed on clean Fe film at 298 K.
UDC 538.971
PACS 68.45.Da
|
