Tungsten Disulfide/Titanium Silicide Composite Used in Water-splitting for Hydrogen Production

Composite of tungsten disulfide and titanium silicide has broad application prospects in water-splitting for hydrogen production as a new type of photocatalyst. It can be successfully prepared by modifying titanium silicide with tungsten disulfide.

Water-splitting for hydrogen production is a process to decompose water to produce hydrogen, converting solar energy into chemical energy. As solar energy and hydrogen energy are clean and efficient sources, water-splitting for hydrogen production is a powerful way to solve the problems of energy shortage and environmental pollution.

Together with the interaction of water and light, semiconductor can be applied in water-splitting for hydrogen production as a photocatalyst. It is usually a kind of powder with specific band gap width and band gap structure. And semiconductor particles suspended in water are regarded as micro-electrodes acting as photoanodes or photocathodes. Even pairs of electrodes are assumed to be on the same particle. The water-splitting for hydrogen production process is simple.

Semiconductor catalyst can be used in the water-splitting for hydrogen production. It involves the following steps:

Step One: Under sunlight, semiconductor absorbs photon energy to excite photogenerated electron-hole pairs. When the semiconductor absorbs photon energy the same as or higher than its bandgap energy, electrons in the valence band will excite a transition to the conduction band, and holes (h+) will be produced in the valence band.

Step Two: Photogenerated charges are separated and migrated on the catalyst surface, and finally reacted with water to produce hydrogen and oxygen. To realize the water-splitting for hydrogen production, semiconductor catalyst must have an appropriate band gap to absorb visible light as much as possible. And the bottom of semiconductor conduction band should be higher than the reduction potential of water while the top of its valence band is lower than the oxidation potential of water.

Step Three: Some photogenerated electron-hole pairs combine inside the catalyst, which will reduce the catalytic activity and the utilization of sunlight.

Composite of tungsten disulfide and titanium silicide, which is prepared by modifying titanium silicide with tungsten disulfide is a highly efficient photocatalyst for the water-splitting for hydrogen production.

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