Tungsten Oxide Mesoporous Structure Factors

Composites calcined in the silica pores of silica acid is converted to form the influential tungsten oxide, tungsten oxide calcination temperature of crystallization and its mesoporous structure. This paper explores at 550-950 ℃ between different calcination temperature impact of mesoporous tungsten oxide structure. Ethanol as a dispersant, and silicotungstic acid silica mesoporous material than m (WO3) / m (SiO2) 3/1, after calcination at different temperatures HF treated tungsten oxide. When the calcination temperature at 550 ℃, almost no diffraction peaks in the small, indicating the degree of structural ordering poor, while N2 adsorption - desorption characterization of the specific surface area of ​​42.7m2 • g-1, and after more than 600 ℃ calcined surface area of ​​68.0m2 • g-1 there were significant decreases when the calcination temperature is 600-750 ℃ ​​when, in the vicinity of 2θ = 1 ° there is a clear diffraction peaks, indicating that the tungsten oxide upon calcination crystalline SiO2 is preferably within the hard model , ordered mesoporous structure after HF treatment of tungsten oxide is preferably, but in a small angle diffraction, no diffraction peaks were observed secondary peaks, indicating that the mesoporous structure is not a good long-range order in the calcination temperature reached 850 and 950 ℃, the structure of the degree of order is poor, there may be caused by high temperature volatile part of the tungsten oxide, thus affecting its structure degree of order.

Small angle XRD patterns of ethanol as a dispersing agent in a different material than silicon tungsten acid mesoporous silicon when, 600 ℃ calcination and get treated by HF tungsten oxide mesoporous materials can be seen when the silicon and silicon-mediated acid hole material ratio m (WO3) / m (SiO2) is 2:1, the figure in the small-angle XRD diffraction peaks, showing that structural order is poor, while the N2 adsorption - desorption characterization of the specific surface area of ​​40.7m2 • g-1, and calcined at 600 ℃ than the surface area of ​​68.0m2 • g-1 significantly decreased compared to when the material ratio 3/1 and 4:1, there is a distinct diffraction peaks near the (211), Description In this mass ratio is preferably within a range of structures can be prepared tungsten oxide mesoporous material. When silicotungstic acid and mesoporous silicon material ratio 5:1 when, in the small-angle XRD pattern of the diffraction peaks is not obvious, indicating that its structure Sequence poor, probably due to the content of tungsten is too high, the silicon oxide outside the tunnel crystallization

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