Adsorption and hydrogenation of CO on Pd(111) and Rh(111) modified by subsurface vanadium

被引：36

作者：

Klötzer, B ^{[1
]}

Unterberger, W ^{[1
]}

Hayek, K ^{[1
]}

机构：

[1] Univ Innsbruck, Inst Phys Chem, A-6020 Innsbruck, Austria

来源：

SURFACE SCIENCE | 2003年 / 532卷

关键词：

low index single crystal surfaces; catalysis; palladium; rhodium; vanadium; carbon monoxide; chemisorption; thermal desorption spectroscopy; computer simulations; models of surface kinetics;

D O I：

10.1016/S0039-6028(03)00136-5

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：

On Pd(111) and Rh(111) a subsurface alloy of V atoms located mainly in the second metal layer is formed by vapor, deposition of V at elevated temperatures. The topmost layer consists exclusively of Pd or Rh atoms in root3 x root3R30degrees geometry. Neither reversible adsorption of CO under UHV conditions nor hydrogenation of CO at atmospheric pressure lead to surface segregation of V compounds. Numerical simulation and threshold temperature programmed desorption analysis of CO TPD series obtained from the clean and V modified samples showed that the presence of subsurface V significantly reduces the desorption energy of molecular CO over a wide coverage range and changes the coverage-dependence of the desorption energy. The presence of subsurface V atoms promotes CO hydrogenation. on both Pd(111) and Rh(111). The enhanced catalytic activity is interpreted in view of the reduced CO desorption energies and of surface roughening induced by subsurface alloy growth. (C) 2003 Elsevier Science B.V. All rights reserved.

引用

页码：142 / 147

页数：6

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