Halotungstate is a kind of tungstate which is mainly composed of oxyhalide, it is a new type of visible light response photocatalyst.
In alkaline earth tungstate, the luminescent intensity of barium tungstate is very weak. Therefore, people try to modify its structure. In 1982, domele and others synthesized barium tungstate with BaF2 and WO3 as raw materials. Ba2WO3F4 is a kind of halotungstate. Through the improvement of its structure. It has been found that ba2wo3f4 has strong fluorescence intensity and strong blue-green luminescence under UV excitation. It can be developed into practical UV and X-ray luminescent materials.
It has also been found that the rare earth tungsten composite halide oxide, which is made by the preparation of the halide tungstate, can glow stronger luminescence performance. For example, the study of lawo4cl shows that it has a strong absorption of X-ray, and its absorption wavelength is just within the range of medical usefulness. It is suitable for X-ray absorption materials. At the same time, it is also found that some rare earth ions show characteristic spectral properties in it. For example, the pure La3WO6Cl3 only has weak luminescence, and when Eu3+ and Tb3+ are doped, La3WO6Cl3 will be activated and emit extremely strong fluorescence.
To sum up, the main function of the halotungstate catalyst is to make X-ray machine. Although it has great application potential, it also has some disadvantages, such as the low efficiency of most of the light quantum, the low catalytic ability in the visible light area and the easy deactivation.
Therefore, the best way is to find a suitable carrier and immobilization method, using carrier to solve the shortcomings of suspension phase photocatalyst, such as easy agglomeration and difficult recovery, and using carrier synergy, can enhance the reaction activity of photocatalyst