Sodium tungsten bronze (NaxWO3, 0<X<1) may be prepared by low temperature hydrothermal synthesis method.
Low Temperature Hydrothermal Synthesis of Sodium Tungsten Bronze
1. Add dilute hydrochloric acid to 0.25 mol•L-1 Na2WO4 solution dropwise under stirring until the pH is around 6.5.
2. The NaBH4 solution was dropped into the Na2WO4 solution at a rate of 2~4d/s.
3. Keep the pH of the solution at 6.5±0.2 by adding dilute hydrochloric acid dropwise.
4. The obtained dark green suspension was allowed to stand for 2 hours. After delaminating, the brown gel was obtained by suction filtration of the brown precipitate, which was washed with water and acetone three times respectively and dried as much as possible.
5. Burn the gel at the range of 400~600°C for 2~4 hours.
6. The obtained product after burning is boiled in 15% oxalic acid solution between 80°C and 100°C for 2 hours.
7. Suction filtration, wash sequentially with water, dilute hydrochloric acid and dilute ammonia, and dry at 110°C to obtain sodium tungsten bronze. Tabletting to determine the infrared spectrum and conductivity of the product.
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