Titanium Dioxide / Tungsten Oxide Composite Semiconductors

The semiconductor material is used as a photocatalyst, due to the limitation of the photocatalytic mechanism, photogenerated electrons and holes can easily be recombined inside and on the surface of the material to affect the photocatalytic efficiency. Pure tungsten oxide nanomaterials also have this problem. By constructing semiconductor / semiconductor heterostructures with other semiconductors, the effective separation of photogenerated electrons and holes can be well promoted, and recombination of photogenerated electron-hole pairs can be avoided.

Titanium dioxide is one of the most commonly used semiconductor materials for photocatalysts but has a wide bandgap of about 3.2 e V and absorbs only ultraviolet light. Tungsten oxide, on the other hand, has a narrow bandgap of 2.25 eV, which absorbs visible light. Therefore, if tungsten oxide is used as a co-catalyst with titanium dioxide, the range of light absorption by titanium dioxide can be broadened. Making it absorb more photon energy for the excitation of photo-generated electrons. At the same time, due to the good match of the band gap of titanium dioxide and tungsten oxide, the separation of photogenerated electron-hole pairs can be effectively promoted and the photocatalytic activity can be promoted.

How to compound titanium dioxide and tungsten oxide becomes a subject worth studying. In recent years, the proposed two-dimensional heterojunction provides an idea for it. We can stack titanium dioxide and tungsten oxide on top of each other to form a vertical heterojunction. Such a heterostructure ensures adequate contact between the titanium and tungsten oxide layers, providing more channels for the transport of photo-generated electrons and holes. Improve the transmission efficiency, but also promote the photo-generated electron-hole pair separation. Therefore, it is of great significance to explore a method for preparing a two-dimensional heterojunction of titanium / tungsten oxide for improving the photocatalytic performance.

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