Formulated a number of copies 0.3mol than concentrations of sodium tungstate solution of 100ml, according to different proportions join RI (OOH). Or where (OOH) n. The clear solution was then transferred to an autoclave, and heated hydrothermal reaction at 140 ℃, detected during the reaction pH of the solution. 24h after filtration, washing (washing with deionized water and ethanol each 3 to 5 times), dried (5O℃) treatment.

Which changes the whole situation, adding organic matter weak acid solution acidity than adding a solution of hydrochloric acid acidity is lower. Since the preparation of the tungsten oxide pyrochlore type process is actually consumed in expansion, increase in the acidity of the solution will help improve the nucleation rate, such that the formation of hydrothermal more grains in a relatively short period of time. And in the material conditions of a constant increase in the number of grains of system generated will lead to reducing the grain radius. From this perspective, the difference between the actual average particle size of the product categories inconsistent with the theory of judgment, may be due to hydrothermal systems PH stability of the product particle size also play a role in the impact, and the effect is more pronounced.

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The pyrochlore-type tungsten trioxide was synthesized by controlling pH value accurately using hydrothermal method. X-ray diffraction data show that the pure pyrochlore-type tungsten trioxide with small grain size is obtained when the initial pH of the solution is 3. The Pt-W O3-C composite catalysts using the pyrochlore-type tungsten trioxide and carbon powder as support were prepared by different processes for polymer exchange membrane fuel cells. The catalytic activity of Pt/(W O3-C ) synthesized by one step hydrothermal and following impregnation method was more active than that of Pt/C measured by cyclic voltammetry (CV) and the single-cell polarization tests. The SEM image shows a better dispersion of Pt/(W O3-C )com posite catalyst than others.

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When using a weak acid-type organic and neutral organics as additives, various additives may also occur their redox reaction in the hydrothermal system. However, since the reactor does not provide an oxidizing agent, organic additives is difficult to oxidation-reduction reaction by itself ultimately generate cO32 one. Experiments show that, to each group after the reaction was added dropwise a solution of calcium chloride solution, no white precipitate formed, the solution described does not generate co wide.

Organic amendments after the hydrothermal reaction in the complete conversion of cO32 a is the ideal result, so that, by means causticizing reaction to convert solution NaZCO3 into NaOH, so as to realize recycling NaoH, traditional oxide tungsten production of raw materials is difficult cycle, high productivity, and poor environmental benefits expected to be resolved many key issues, has obvious practical significance.

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Research tungsten oxide photochromic almost half a century, but uncertainty and change color to characterize the selected light source so that the unity of development is very slow. 1973 Dbell use urbach rules: K = K0exp {-B (E0g-hv) / KT} where hv is the radiation energy, features B and all the material constants. Selecting the appropriate light source, is the key to the realization of discoloration. The current sources are mainly two kinds of pressure mercury lamp and a high pressure xenon lamp, wattage of light source of different, there are a mercury lamp 500W, 400W, 250W, 150W, etc; xenon lamp has a 50 () W, 200W, 150W, 75W and the like. Although only change the wattage of light intensity, but it reflects the color properties of tungsten oxide. In particular, to meet the different needs from the viewpoint of the photochromic material under the sun light is sunglass manufacturers have been pursued, and long-term stability of high-band color material is desired field of information, and requires a material having a display aspect of a fast decolorization performance. Therefore, light-induced oxidation of tungsten exploration is still a long way to go discolored material.

Most scholars are detected by UV spectroscopy after light irradiation discoloration of materials, but the method can not measure the discoloration process in a short time, so we discoloration of the mechanism and process of its difficult to accurately grasp. Electrons produced until 1993 using a highly sensitive technique to detect TR tungsten oxide in a few seconds after the light discoloration, gives the decolorization tungsten oxide reversible process is the conclusion at the same time, and proposed rate and colored light when empty Point of view related to the number. In addition, by EsR, XPS and other means can also check the process side of the tungsten oxide discoloration, but the two instruments are very expensive, and therefore can not serve as a common means of representation.

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