Tungsten oxide nanopowder applying for nano-ceramic dispersion solution has photocatalytic property, but its photocatalytic activity needs to be improved. That is to say, it is necessary to carry out related researches on the method of increasing tungsten oxide photo-generated carriers. Researchers have found an effective way to increase photogenerated carriers --- metal loading.
The reason why metal loading method can be used to improved photogenerated carriers of tungsten oxide is that the work ding of the metal is higher than that of tungsten oxide semiconductor. So, the photogenerated electrons will flow from the semiconductor to the metal, and the photogenerated holes left on the surface of the semiconductor, which will bend the energy band of the semiconductor surface upward to form Schottky barrier. The Schottky barrier acts as an electron trapping trap that blocks the recombination of photogenerated electrons and holes. Some common seen loaing metals are Pt (platinum), Pd (palladium), Ag (silver), Au (gold) and Ru (ruthenium).
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