Tungsten Oxide Photocatalytic Ability to Improve

In the development of photocatalysts, tungsten oxide as a stable, band structure suitable material can be modified to obtain a visible light response of high activity photocatalyst. Due to the lower valence band position of tungsten oxide, the forbidden band width is variable, it has excellent photoelectric properties, UV - visible light catalysis and other characteristics, so it can replace the old catalyst.

There are many ways to improve the photocatalytic ability of tungsten oxide, mainly in the following categories:

（1）Precious metal load: A Schottky barrier that blocks recombination of photogenerated electrons and holes is formed by loading noble metal such as Pt on the surface of tungsten trioxide. The Schottky junction captures photogenerated electrons in the conduction band into Pt, thereby reducing the recombination efficiency of photogenerated electrons and holes. However, the high price of precious metals and the cost hinder the development of such photocatalysts.

（2）Morphology and structural improvement: By limiting the width of the tungsten oxide nanowires within 1 nm to produce a quantum confinement effect, the near-infrared absorption intensity of the tungsten oxide material is enhanced and a higher photocatalytic activity is obtained.

（3）Increasing Oxygen Defects: Tungsten trioxide films with many oxygen defects and a band gap of 2.0 eV were prepared by hydrothermal method. This oxygen deficiency increases the charge concentration on the surface of tungsten trioxide and increases the chemisorption of oxygen molecules on the surface. At the same time, the oxidative capacity of reactive oxygen ions is increased, thereby broadening the light response range of the tungsten trioxide to the infrared region and improving the catalytic efficiency.

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