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RESEARCH PRODUCT

Properties of Multi Phase Interfaces on the Tungsten Trioxide Particles in the Thin Films

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description

A wide spectrum of physical and chemical properties of thin films of tungsten trioxide compounds depend on composition, constitution and structure of the film, interaction with environment, and the type of external influences/excitations. The reason is the non-stoichiometric nature of transition metal oxides and properties of d-electrons. The short range order of non-stoichiometric compounds or phases of WO3 has a strong perovskite arrangement of tungsten and oxygen ions [1, 2]. The smallest crystalline clusters of perovskite short range order consist 6÷9 of [WO6]-octahedrons. One of the structural peculiarities-features of tungsten trioxide, related to non-stoichiometry, is a variety of [WO6]-octahedron sharing in structural units of pure tungsten oxide compounds with crystalline patterns (oxygen based non-stoichiometry) [1]. An other basic common peculiarity-feature of tungsten trioxide phases is the ion insertion /extraction phenomenon (ion insertion based non-stoichiometry). The homogeneity range of non-stoichiometry of a corresponding phase is 0.1÷1.0 atomic units. The surface of all these compounds has a high adsorption capability for different chemical species and a high catalytic activity.