Nano semiconductor material used as photocatalyst to photolysis water has gained well efficiency. TiO2 has high catalytic activity and stability is widely used as a kind of photocatalytic material. But its band gap is big (~3.2 eV), it can only be motivated by ultraviolet with short wave length, its light transaction efficiency is low (~4%). Tungsten oxide is an indirect band series transition semiconductor material. Compared to TiO2, it has narrow band gap (2.5~3.0 eV), the relevant absorbing wave length is 410~500nm and well photoelectric responsive property in visible light area.
Tungsten oxide thin film electrode preparation method:
Raw material: FTO glass; tungstic acid; hydrogen peroxide; acetone.
(1) Be ready with clean FTO glass as the substrate of depositing WO3. Cut FTO glass into 1.2cm*2.5cm pieces and clean it by ultrasound and ultraviolet. The clean and flatness of FTO substrate has big effect on adhesive force and uniformity of thin film electrode. So before depositing thin film electrode, the FTO glass should be well cleaned. Firstly, clean the dirties on the surface by ethyl alcohol. Then put the substrate in acetone and ultrasound for 30min to eliminate the ethyl alcohol and oil contamination on the surface. After that, ultrasound it in water for 20 min to eliminate the residual acetone. Finally dry it by nitrogen gas. Then put it into ultraviolet disinfectant tank to sterilize.
(2) Weigh 0.02g tungstic acid and dissolve it by 20ml 30% hydrogen peroxide. Stay it for 12 hours to obtain transparent tungstic acid solution, it will be used as electrolyte solution to deposit WO3.
(3) Use substrate obtained from step (1) as working electrode, measure 30 micro liter tungstic acid solution, dispensing it evenly on the surface of FTO conductive glass. Dry it under room temperature, colorless thin film is obtained.
(4) Put the deposited thin film from step (3) into tube furnace, calcinating it for 2 hours under 500℃, colorless WO3 electrode is obtained .