Studies of the oxidation of iron by water vapour using X-ray photoelectron spectroscopy and QUASES™

被引：204

作者：

Grosvenor, AP

Kobe, BA

McIntyre, NS

机构：

[1] Univ Western Ontario, Surface Sci Western, Western Sci Ctr, London, ON N6A 5B7, Canada

[2] Univ Western Ontario, Dept Chem, London, ON N6A 5B7, Canada

来源：

SURFACE SCIENCE | 2004年 / 572卷 / 2-3期

基金：

加拿大自然科学与工程研究理事会;

关键词：

X-ray photoelectron spectroscopy; iron; water; oxidation; tunneling; polycrystalline surfaces;

D O I：

10.1016/j.susc.2004.08.035

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The oxidation of Fe by water (H2O) vapour was studied using X-ray photoelectron spectroscopy (XPS) and QUASES(TM). The results indicated that the oxide formed at 25degreesC and 150degreesC was thinner than that formed when oxygen (02) gas was present. The kinetics of the reaction were studied and found to follow a direct logarithmic relationship at both 25degreesC and 150degreesC. At 150degreesC, a change in mechanism occurred after an oxide layer of approximately 0.7nm had formed. It was determined the mechanism changed from a temperature-independent place-exchange to a temperature-dependent field-driven mechanism. The decreased rate of oxide growth in water vapour compared to that in O-2 is proposed to result from the presence of H within the oxide as well as adsorbed to the surface. Its location within the oxide acts to restrict the amount of diffusion that can occur, while its presence on the surface restricts the number of surface states available for further adsorption of H2O. The slow conversion of hydroxide to oxide, as well as differences in transport properties between hydroxides and oxides, were also felt to decrease the thickness of the layer formed compared to equivalent reactions with oxygen. (C) 2004 Elsevier B.V. All rights reserved.

引用

页码：217 / 227

页数：11

共 31 条

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