One Step Hydrothermal Preparation of Tungsten Trioxide Powder

Metal oxides play a key role in the development of many advanced functional materials and smart devices. Among many metal oxides, tungsten trioxide (WO₃) is a kind of unique material, which has attracted much attention due to its versatility. For example, WO₃ is an n-type semiconductor with various crystal forms, band gap width of 2.5-2.8ev, and visible light response characteristics. Therefore, WO₃ can be used as light sensing device, photochromic device, transparent electrode, visible light catalyst, etc.

It is very important to synthesize high performance tungsten trioxide. The shape and size of the materials obtained by different synthesis methods are different, which affects the properties of the materials. There are many synthesis methods of WO₃, such as solid phase method, deposition method, hydrothermal method and so on. Among them, hydrothermal method is divided into one step hydrothermal synthesis and two-step hydrothermal synthesis. This paper mainly introduces the one step hydrothermal synthesis of tungsten trioxide powder.

In one step hydrothermal synthesis, WO₃ with different morphology and photoelectric properties can be prepared by adjusting the concentration of sodium tungstate and the pH value of the precursor:

(1)Weigh 0.825g of sodium tungstate dihydrate and 0.29g of sodium chloride respectively, add 75ml of water, make the concentration of the sodium tungstate dihydrate in water 0.033mol/l, ultrasound 5min, adjust the pH value of the solution with hydrochloric acid under magnetic stirring, continue stirring for 1h, and obtain the precursor solution;

(2)Transfer the precursor solution to the reactor, conduct hydrothermal reaction at 180 ℃ for 24 hours, naturally cool to room temperature, wash the product with distilled water and anhydrous ethanol in turn, and dry it after centrifugation to obtain tungsten trioxide powder.

The one step hydrothermal synthesis method has the advantages of simple operation, mild synthesis conditions and good repeatability, and reduces the production cost. The prepared WO₃ has high photodegradation efficiency.

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