Coprecipitation Preparing Tungsten Trioxide

Coprecipitation refers to coprecipitation of two or more cations in solution, they are present in the homogeneous solution, adding precipitating agent, after the precipitation reaction, obtaining uniform precipitation of various components. Advantages of coprecipitation method, the first is getting directly nanopowders uniform chemical composition by a variety of chemical reactions in solution, and the second is easy to prepare small particle size and distribution of nano-powder materials.

The steps to make tungsten trioxide by Coprecipitation is that taking firstly a certain percentage of 1mol / L of Na₂WO₄ solution and Na₂SnO₄ solution, dropping them slowly to boiling dilute H₂SO₄ after mixing, and stirring constantly to generate the precipitation in the aging, and washing, filtering, drying and calcining to obtain SnO₂-WO₃ powder. The study shows the addition inhibits the growth of SnO₂ WO₃ grains, increases the sensitivity of its gas, the doping amount of 0.5% is optimum.

The study shows Sol - tungsten trioxide can be prepared by coprecipitation method, adding ammonia and suitable WCl6 and TiCl (4wt %) aqueous solution to form W (OH) ₆ and Ti (OH) ₄, after the separation can obtain 3 ~ 9nm tungsten trioxide powder. The study shows that the smaller the particle, the more uniform particle size.

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