CO和CO₂在氧化和还原的SrTiO₃(100)表面上的吸附与反应。

Adsorption and reaction of CO and CO2 on oxidized and reduced SrTiO3(100) surfaces.

作者信息

Azad Samina, Engelhard Mark H, Wang Li-Qiong

机构信息

Environmental Molecular Science Laboratories, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.

出版信息

J Phys Chem B. 2005 May 26;109(20):10327-31. doi: 10.1021/jp045864b.

DOI:10.1021/jp045864b

PMID:16852251

Abstract

The adsorption and reaction of CO and CO(2) on oxidized and reduced SrTiO(3)(100) surfaces have been studied with temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). XPS results indicate that the oxidized SrTiO(3)(100) surfaces are nearly defect-free with predominantly Ti(4+) ions whereas the sputter-reduced surfaces contain substantial amounts of defects. Both CO and CO(2) are found to adsorb weakly on the oxidized SrTiO(3)(100) surfaces. On sputter-reduced surfaces, enhanced reactivity of CO and CO(2) is observed due to the presence of oxygen vacancy sites, which are responsible for dissociative adsorption of these molecules. Our studies indicate that the CO and CO(2) molecules exhibit relatively weaker interactions with SrTiO(3)(100) compared to those with TiO(2)(110) and TiO(2)(100) surfaces. This is most likely an influence of the Sr cations on the electronic structure of the Ti cations in the mixed oxide of SrTiO(3).

摘要

利用程序升温脱附（TPD）和X射线光电子能谱（XPS）研究了CO和CO₂在氧化和还原的SrTiO₃(100)表面上的吸附和反应。XPS结果表明，氧化的SrTiO₃(100)表面几乎无缺陷，主要为Ti(4+)离子，而溅射还原的表面含有大量缺陷。发现CO和CO₂在氧化的SrTiO₃(100)表面上吸附较弱。在溅射还原的表面上，由于存在氧空位，CO和CO₂的反应活性增强，这些氧空位导致这些分子的解离吸附。我们的研究表明，与TiO₂(110)和TiO₂(100)表面相比，CO和CO₂分子与SrTiO₃(100)的相互作用相对较弱。这很可能是Sr阳离子对SrTiO₃混合氧化物中Ti阳离子电子结构的影响。