What’s Halide Ammonium Tungstate

Halide tungstate, the new type of visible light responsive photocatalyst, is a kind of tungstate which is mainly composed of halogen oxygen compounds.

The luminous intensity of barium tungstate is much weaker than that of other alkaline earth metal tungstate, so people try to modify the structure of barium tungstate. In 1982, Domesle synthesized fluorinated barium tungstate by using BaF₂ and WO₃ as raw materials. Ba₂WO₃F₄ is a kind of halogen tungstate, which has strong fluorescence intensity. With its strong blue-green luminescence under ultraviolet excitation, it can be developed as a practical UV and X ray luminescent material.

It is also found that rare earth tungsten composite halides can be produced with stronger luminescence properties by the preparation of halogen tungstate. LaWO₄Cl, for example, has a strong absorption of X light, of which the absorption wavelength is just within the useful range of medicine. So it is suitable for X light absorption materials. At the same time, some rare earth ions show special spectral properties. Pure La₃WO₆Cl₃, for example, the weakly luminescent chemical compound will emit a very strong fluorescence after doping with Eu³⁺ and Tb³⁺.

To sum up, the main qpplication of halogen tungstate catalyst is to make X ray machine. Although it has great potential for application, there are some disadvantages. For example, its most light quantum efficiency is not high, its catalytic capacity in the visible region is very low and it is easy to deactive. The best way is to find the appropriate carrier and immobilization method. Solving the shortcomings of suspension phase photocatalyst such as easy to agglomerate and difficult to recover need the carrier. Moreover, the photocatalytic activity of the photocatalyst can be enhanced by the synergistic action of the carrier.

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