Polarization-Dependent Total-Reflection Fluorescence XAFS Study of Mo Oxides on a Rutile TiO2(110) Single Crystal Surface
Polarization-Dependent Total-Reflection Fluorescence XAFS Study of Mo Oxides on a Rutile TiO2(110) Single Crystal Surface
复制标题
金红石 TiO2(110) 单晶表面上 Mo 氧化物的偏振相关全反射荧光 XAFS 研究
DOI：
10.1021/jp9820368
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发表时间：
1998
影响因子：
3.3
通讯作者：
Y. Iwasawa
中科院分区：
文献类型：
--
作者：
W. Chun;K. Asakura;Y. Iwasawa
采用偏振相关全反射荧光X射线吸收精细结构（PTRF-EXAFS）方法，在单晶表面的3个不同方向上研究了分散良好的Mo氧化物在TiO 2（110）表面的结构。以（NH 4）6 Mo 7 O24·4 H2O为载体，经超纯水浸渍、773 K焙烧制备了负载型Mo氧化物催化剂模型样品。直接比较的EXAFS观测值和计算的三维模型结构的基础上进行。我们发现各向异性的Mo二聚体优先在TiO 2（110）表面形成，Mo-Mo距离（0.335 nm）平行于表面的[110]方向。还发现Mo二聚体附着在表面上，显示Mo-Ti（界面）距离为0.296 nm。
The structure of well-dispersed Mo oxides on TiO2(110) was investigated by means of polarization-dependent total-reflection fluorescence X-ray absorption fine structure (PTRF-EXAFS) in three different directions of the single-crystal surface. A model sample for supported Mo oxide catalysts was prepared by impregnation of (NH4)6Mo7O24·4H2O dissolved in ultrapure water, followed by calcination at 773 K. Direct comparison of the observed EXAFS and the calculated one was performed based on three-dimensional model structures. We found that anisotropic Mo dimers were preferentially formed on the TiO2(110) surface, with Mo−Mo distance (0.335 nm) parallel to the [110] direction of the surface. It was also found that the Mo dimers were attached to the surface, showing Mo−Ti (interfacial) distance at 0.296 nm.