吸附在Pt(S)-[n(100)x(110)]电极上的一氧化碳的原位红外反射吸收光谱

In situ infrared reflection absorption spectroscopy of carbon monoxide adsorbed on Pt(S)-[n(100)x(110)] electrodes.

作者信息

Mikita Kosuke, Nakamura Masashi, Hoshi Nagahiro

机构信息

Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.

出版信息

Langmuir. 2007 Aug 14;23(17):9092-7. doi: 10.1021/la7007182. Epub 2007 Jul 11.

DOI:10.1021/la7007182

PMID:17625897

Abstract

Structural effects on the adsorption of CO have been studied using infrared reflection absorption spectroscopy (IRAS) on Pt(S)-[n(100)x(110)] surfaces (n = 2, 5, 9) that have densely packed kink atoms in the step. Coverage and potential dependence of the IRAS spectra are scrutinized. On-top and bridge-bonded CO are found on all of the surfaces examined. CO is adsorbed on only kink at low coverage (thetaCO < or = 0.2). Adsorbed CO on kink gives an IR band at lower frequency than that on step. CO is adsorbed on both kink and terrace at 0.3 < or = thetaCO. Water is adsorbed on the terrace of Pt(510) n = 5 and Pt(910) n = 9 at low CO coverage, but water is not found on Pt(210) n = 2 of which the first layer is composed of only kink atoms. It is suggested that coadsorbed water on the terrace enhances the activity for the oxidation of adsorbed CO on the kink remarkably.

摘要

利用红外反射吸收光谱（IRAS）对Pt(S)-[n(100)x(110)]表面（n = 2、5、9）上CO的吸附结构效应进行了研究，这些表面在台阶处有密集堆积的扭结原子。仔细研究了IRAS光谱的覆盖度和电位依赖性。在所研究的所有表面上均发现了顶位吸附和桥位吸附的CO。在低覆盖度（θCO≤0.2）时，CO仅吸附在扭结处。扭结处吸附的CO产生的红外波段频率低于台阶处的。当0.3≤θCO时，CO同时吸附在扭结和平台上。在低CO覆盖度下，水吸附在Pt(510)（n = 5）和Pt(910)（n = 9）的平台上，但在第一层仅由扭结原子组成的Pt(210)（n = 2）上未发现水。研究表明，平台上共吸附的水显著提高了扭结处吸附的CO的氧化活性。