期刊
SURFACE SCIENCE
卷 605, 期 17-18, 页码 1754-1762出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.susc.2011.06.017
关键词
Oxidation; Fe(111); Methanol adsorption; STM; XPS; Surface structure
资金
- EPSRC
The oxidation of Fe(111) was studied using Auger electron spectroscopy (AES), low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS) and scanning tunnelling microscopy (STM). Oxidation of the crystal was found to be a very fast process, even at 200 K, and the Auger O signal saturation level is reached within similar to 50 x 10(-6) mbar s. Annealing the oxidised surface at 773 K causes a significant decline in apparent surface oxygen concentration and produces a clear (6 x 6) LEED pattern, whereas after oxidation at ambient temperature no pattern was observed. STM results indicate that the oxygen signal was reduced due to the nucleation of large, but sparsely distributed oxide islands, leaving mainly the smooth (6 x 6) structure between the islands. The reactivity of the (6 x 6) layer towards methanol was investigated using temperature programmed desorption (TPD), which showed mainly decomposition to CO and CO(2), due to the production of formate intermediates on the surface. Interestingly, this removes the (6 x 6) structure by reduction, but it can be reformed from the sink of oxygen present in the large oxide islands simply by annealing at 773 K for a few minutes. The (6 x 6) appears to be a relatively stable, pseudo-oxide phase, that may be useful as a model oxide surface. (C) 2011 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据