Yellow tungsten oxide, namely tungsten trioxide or WO3, is a common semiconductor photocatalytic material. Certainly, there are other common semiconductor photocatalytic materials such as TiO2, ZnO, Fe2O3 and Bi2WO6. Wherein, so far, the most studied material is TiO2. However, due to the shortcomings of TiO2 - wide band gap and low conversion efficiency of visible light, people have begun to improve the light utilization efficiency of photocatalysts from two directions:

A yellow tungsten oxide composite film uses amorphous tungsten oxide as a matrix, and the SiO2 nanocrystals are uniformly distributed in the amorphous tungsten oxide. Some experts prepared such a composite film with a spectral modulation amplitude at 633 nm of 46%, a coloring time of 8 s, and a fade time of 4.3 s through the following steps:

As a new energy-saving building material, WO3 electrochromic glass has attracted more and more attention. For example, some experts use a WO3 thin film having nanocrystalline mosaic structure as an electrochromic material, and combine it with NiO to assemble an electrochromic device – an electrochromic glass, with high spectral modulation amplitude.

As a photocatalyst, yellow tungsten oxide (WO3) has significant volume effects, surface effects, quantum size effects, and macro quantum tunnel effects, so that it has a wide range of applications in environmental pollution purification and energy regeneration, and therefore it has attracted much attention. Compared with commonly used photocatalysts such as TiO2 and ZnO, yellow tungsten oxide has a smaller forbidden band width and a larger light absorption range, thus it can use visible light (accounting for nearly half of the solar radiation energy) more effectively.