Ultrafine yellow tungsten oxide is a yellow powder with a large specific surface area, which can be prepared by hydrothermal method. There are three obvious characteristics of hydrothermal method:
1. Accelerate hydrolysis reaction.
2. Accelerate reaction between complex ions.
3. The oxidation-reduction potential of the reactants changed obviously.
Hydrothermal Method to Produce Yellow Tungsten Oxide
Step one: Weigh a certain ratio of sodium tungstate dehydrate (Na2WO4?2H2O) and sodium chloride into distilled water. The concentration of sodium tungstate in distilled water should be well controlled in a certain range.
Step two: Process sodium tungstate solution by ultrasonic treatment. Adjust pH value by hydrochloric acid solution on a magnetic stirrer. And then keep stirring to get polymeric precursor solution.
Step three: Move precursor solution to reactor, via hydrothermal reaction for some time. And then cool it down to room temperature. After that, wash the obtained product with distilled water and absolute ethyl alcohol. WO3 can be obtained after centrifugal drying.
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