XANES and XPS study of silica-modified titanias prepared by the glycothermal method
XANES and XPS study of silica-modified titanias prepared by the glycothermal method
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DOI：
10.1021/cm040045p
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发表时间：
2005-01
影响因子：
8.6
通讯作者：
S. Iwamoto;and Seiu Iwamoto;M. Inoue;H. Yoshida;Tsunehiro Tanaka;K. Kagawa
中科院分区：
文献类型：
--
作者：
S. Iwamoto;and Seiu Iwamoto;M. Inoue;H. Yoshida;Tsunehiro Tanaka;K. Kagawa
通过糖热法制备了具有高热稳定性的锐钛矿结构的二氧化硅改性二氧化钛，并应用 XANES 和 XPS 技术研究了这些样品中 Si 原子的局部结构。为了进行比较，通过在二氧化钛上浸渍 TEOS 或硅溶胶制备了两种二氧化硅改性二氧化钛样品。 XPS测定的糖热产物中Si原子的表面浓度小于浸渍法制备的参考样品的表面浓度，表明在糖热产物中硅原子高度分散在锐钛矿基体中。由于四面体配位的 Si 原子，糖热产物的 Si K 边 XANES 光谱在 1847.1 eV 处显示出主峰。然而，检测到 1849 eV 处的肩峰，这归因于八面体配位的 Si 原子。糖热产物中后一种组分的比例大于参考样品中的比例，并且随着 Si c 的增加而变大。
Silica-modified titania with the anatase structure having high thermal stabilities was prepared by the glycothermal method, and XANES and XPS techniques were applied for investigating the local structure of Si atoms in these samples. For comparison, two silica-modified titania samples were prepared by impregnation of TEOS or silica sol on titania. The surface concentration of Si atoms in the glycothermal product, as determined by XPS, was smaller than those of the reference samples prepared by the impregnation method, suggesting that in the glycothermal product silicon atoms are highly dispersed in the anatase matrix. The Si K-edge XANES spectra of the glycothermal products exhibited a main peak at 1847.1 eV due to the tetrahedrally coordinated Si atoms. However, a shoulder peak at 1849 eV was detected, which was attributed to the octahedrally coordinated Si atoms. The proportion of the latter component in the glycothermal product was larger than those in the reference samples and became large as the Si c...