Compared with titanium dioxide, tungsten trioxide (WO₃) nano-powder can efficiently photocatalytically degrade methylene blue due to its narrow band gap, which can only absorb ultraviolet light. However, the technical problem of photocatalytic degradation of methylene blue by tungsten trioxide is to select catalysts with high catalytic activity.

Tungsten trioxide is not only a kind of n-type semiconductor material, but also a kind of "d0" oxide. This dual identity makes tungsten trioxide have catalytic, optical and electrical properties at the same time, making it a basic material for industrial manufacturing such as smart windows, electronic packaging, secondary lithium batteries, gas sensors and so on.

Tungsten oxide is a typical transition metal oxide with a band gap of 2.4-2.8eV. It belongs to a typical n-type semiconductor. Tungsten-based oxides not only act as catalysts, electrochromic, battery electrodes, solar energy absorbing materials and invisible materials, but also have the properties of pressure sensitive, thermal sensitive and gas sensitive semiconductor functional materials.

Gas-sensitive materials refer to a class of gas-sensitive materials. Usually, the resistance of these materials varies with the surrounding gas environment. Using the so-called selectivity and sensitivity, it can not only distinguish different kinds of gases, but also identify the concentration of specific gases. At present, the sensitive components made of gas-sensitive materials have entered the practical stage in the petroleum, chemical industry, coal mine, automobile manufacturing, electronics, power generation and other industrial departments, as well as environmental monitoring, residential harmful gas alarm, national defense and other departments.