3D quasi-vertical WO3?0.33H2O film can be prepared by the following steps: preparing a hydrated WO3 nanosheet sol; electrodepositing.
First, prepare a hydrated WO3 nanosheet sol: 5g of tungstic acid was dissolved in 60mL of hydrogen peroxide at 95°C, cooled to room temperature, and diluted to 200mL with an equal volume of ethylene glycol and deionized water to obtain a stable peroxo-tungstic acid solution (PTA) of a concentration of 0.1mol/L. The obtained PTA solution was then mixed in equal volume with deionized water and condensed and refluxed at 120°C to give a light yellow sol, and then heating was stopped.
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Next, carry out an electrodepositing process: after cooling the PTA sol to about 80°C, a constant voltage multi-step electrodeposition was performed. By a three-electrode method, the cleaned FTO conductive glass was used as a working electrode, a platinum plate (1.5cm x 1.5cm) was used as a counter electrode, and the reference electrode was Ag/AgCl (3mol/L KCl). First, deposition was carried out for 30s at a voltage of -1V to enhance the bonding force between the film and the FTO; then, it was deposited at a voltage of -0.5V for 600s. After the deposition is completed, the obtained film is immersed in ethanol, and air-dried to obtain a tungsten trioxide film.
