In recent years, semiconductor photocatalytic research has developed rapidly. Wherein, yellow tungsten oxide (tungsten trioxide /WO3) has become more and more attractive as a photocatalyst. Tungsten trioxide catalyst has the advantages of stable catalytic performance, no secondary pollution, no photo-corrosion and no toxicity. Therefore, it is widely used in photocatalytic water splitting. Some experts researched the photocatalytic activity of WO3 and found that the optimal oxygen production of WO3 is about 79.9 μmol/(L·h) under visible light radiation.

Yellow tungsten oxide is also called tungsten trioxide (WO3). Tungsten trioxide is an electrochromic material that has been widely investigated and is expected to replace traditional energy-saving glasses. And WO3 thin film is the most favorable inorganic electrochromic film that has been researched. Some experts have prepared WO3 electrochromic film by the sol-gel method, and studied the effect of heat treatment temperature on the discoloration characteristics and structure of the obtained WO3 films.

The photocatalytic performance of nonmetal-doped yellow tungsten oxide as a photocatalyst is improved compared to pure WO3. This is because compared with O2p orbitals, nonmetal ions such as C, N, F and S have orbits with relatively high energy. Substituting some of O atoms in semiconductor oxides (such as WO3) with the abovementioned atoms may increase the position of the valence band of the semiconductor, reduce the semiconductor band gap width, and make its absorption edge red shift.

In the past few years, many users of ammonium paratungstate (APT) have a more strict quality requirement in its quality, including particle-size and apparent density, crystal shape, etc. Thus, a new preparation of APT with coarse grain that meets the requirements of industry has been introduced.