XAFS Study of Tungsten L1- and L3-Edges: Structural Analysis of WO3 Species Loaded on TiO2 as a Catalyst for Photo-oxidation of NH3
XAFS Study of Tungsten L1- and L3-Edges: Structural Analysis of WO3 Species Loaded on TiO2 as a Catalyst for Photo-oxidation of NH3
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DOI：
10.1021/jp711250f
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发表时间：
2008-04
影响因子：
3.7
通讯作者：
S. Yamazoe;Y. Hitomi;T. Shishido;Tsunehiro Tanaka
中科院分区：
文献类型：
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作者：
S. Yamazoe;Y. Hitomi;T. Shishido;Tsunehiro Tanaka
我们分析了X射线吸收精细结构（XAFS）光谱的W L1-和L3-边缘，以确定各种W物种的结构上的TiO 2。在所有含W样品（WO 3，Na 2 WO 4，Cr2 WO 6，Ba 2NiWO 6，（NH 4）10 W12 O 41·5 H2O，Sc2 W3 O 12，H3 PW 12 O 40·13 H2O，和TiO 2负载的WO 3样品）的WL 3边X射线吸收近边结构（XANES）的二阶导数谱中观察到两个2 p → 5d跃迁。这两个跃迁可以归属于被配体场分裂的5d轨道。5d轨道的分裂与W L1边XANES谱的边前峰面积成线性关系。八面体和四面体W模型的密度泛函理论（DFT）计算支持这种线性关系。在此线性关系的基础上，我们估计了各种W物种在TiO 2上的结构。所得结构与W L3边扩展X射线吸收精细结构（EXAFS）曲线拟合分析结果一致。另外，我们发现八头龙...
We analyzed the X-ray absorption fine structure (XAFS) spectra of W L1- and L3-edges in order to determine the structure of various W species on TiO2. Two 2p → 5d transitions were observed in the second derivative of the W L3-edge X-ray absorption near-edge structure (XANES) spectra of all samples containing W (WO3, Na2WO4, Cr2WO6, Ba2NiWO6, (NH4)10W12O41·5H2O, Sc2W3O12, H3PW12O40·13H2O, and TiO2-loaded WO3 samples). These two transitions can be assigned to 5d orbitals split by the ligand field. The split in the 5d orbital has a linear relationship with the area of pre-edge peak of the W L1-edge XANES spectrum. This linear relationship is supported by density functional theory (DFT) calculations of the octahedral and tetrahedral W models. On the basis of this linear relationship, we estimated the structure of various W species on TiO2. The obtained structure is in accordance with the curve fitting analysis of W L3-edge extended X-ray absorption fine structure (EXAFS). Additionally, we found that the octah...