Mixed water/OH structures on Pd(111)

被引：38

作者：

Clay, Chris ^{[1
]}

Cummings, Linda ^{[1
]}

Hodgson, Andrew ^{[1
]}

机构：

[1] Univ Liverpool, Surface Sci Res Ctr, Liverpool L69 3BX, Merseyside, England

来源：

SURFACE SCIENCE | 2007年 / 601卷 / 02期

基金：

英国工程与自然科学研究理事会;

关键词：

desorption; surface reaction; palladium; water; OH;

D O I：

10.1016/j.susc.2006.10.024

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：

Chemisorbed O and water react on Pd(111) at low temperatures to form a mixed OH/H2O layer with a (root 3 x root 3)R30 degrees registry. Reaction requires at least two water molecules to each 0 before the (2 x 2)0 islands are consumed, the most stable OH/water structure being a (OH + H2O) layer containing 0.67 ML of oxygen, formed by the reaction 3H(2)O + O -> 2(H2O + OH). This structure is stabilised compared to pure water structures, decomposing at 190 K as OH recombines and water desorbs. The (root 3 x root 3)R30 degrees - (OH + H2O) phase cannot be formed by O/H reaction and is distinct from the (root 3 x root 3)R30 degrees structure formed by O/H coadsorption below 200 K. Mixed OH/water structures do not react with coadsorbed H below 190 K on Pd(111), preventing this phase catalyzing the low temperature H-2/O-2, reaction which only occurs at higher temperatures. (c) 2006 Elsevier B.V. All rights reserved.

引用

页码：562 / 568

页数：7

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