Preparation method of monoclinic tungsten trioxide

A technology of tungsten trioxide and monoclinic crystal, applied in the direction of tungsten oxide/tungsten hydroxide, nanotechnology, etc., to achieve good reproducibility, uniform particle size distribution, and avoid production

Active Publication Date: 2016-09-07
HENAN UNIV OF SCI & TECH
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Problems solved by technology

[0003] At present, the preparation of tungsten trioxide mainly includes direct calcination of tungstates such as ammonium metatungstate or ammonium paratungstate, or the preparation of tungsten trioxide by hydrometallurgy using sodium tungstate as raw material. Crystalline tungsten oxide mixture, at present, there is no relevant literature in the prior art to characterize the preparation method of monoclinic tungsten trioxide

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[0024] A preparation method of monoclinic tungsten trioxide, which will be able to ionize WO in solution 4 2- The soluble tungstate (ammonium metatungstate is used as an example in this description) is prepared by hydrothermal method after stirring and mixing with nitric acid solution. Include the following steps:

[0025] (1) Measure a certain volume of commercially available nitric acid (63vol.% concentration, 1.4g / ml density) to prepare a nitric acid solution with a concentration of 12.14~14mol / L, and place it in a clean beaker.

[0026] (2) Weigh 303g of ammonium metatungstate powder [(NH 4 ) 6 h 2 W 12 o 40 ], where the ammonium metatungstate used is a white crystalline powder. Add to the beaker in step 1, stir for 10-30min to make it evenly mixed. During this process, the main reactions that take place are:

[0027] (NH 4 ) 6 h 2 W 12 o 40 +8H 2 O=6NH 4 + +12WO 4 2- +18H +

[0028] WO 4 2- +2H + =H 2 WO 4

[0029] (3) Immediately transfer the r...

Embodiment 1

[0038] (1) Weigh 303g of ammonium metatungstate powder [(NH 4 ) 6 h 2 W 12 o 40 ], where ammonium metatungstate is a white crystalline powder.

[0039] (2) Measure 347ml of commercially available nitric acid solution (mass concentration is 63%, density is 1.4g / ml.), put it in a clean beaker, and dilute the solution in this beaker to 400ml with deionized water.

[0040] (3) Add the ammonium metatungstate in step (1) into the above-mentioned beaker containing the nitric acid solution, and stir for 30 minutes to make it evenly mixed.

[0041] (4) Transfer the reaction system obtained in step (3) to a polytetrafluoroethylene-lined hydrothermal reaction kettle, place it in a vacuum drying oven, and react at 150°C for 20 hours, then take it out, and cool it at room temperature. A hydrothermal product is obtained.

[0042] (5) The hydrothermal reaction product obtained in step (4) is subjected to vacuum filtration, and the suction filtration is multiple suction filtration. Slo...

Embodiment 2

[0045] (1) Weigh 303g of ammonium metatungstate powder [(NH 4 ) 6 h 2 W 12 o 40 ], where ammonium metatungstate is a white crystalline powder.

[0046] (2) Measure 380ml of commercially available nitric acid solution (mass concentration: 63%, density: 1.4g / ml.), and place it in a clean beaker.

[0047] (3) Add the ammonium metatungstate in step (1) into the above-mentioned beaker containing the nitric acid solution, and stir for 30 minutes to make it evenly mixed.

[0048] (4) Transfer the reaction system obtained in step (3) to a polytetrafluoroethylene-lined hydrothermal reaction kettle, place it in a vacuum drying oven, and react at 170°C for 15 hours, then take it out, and cool it at room temperature. A hydrothermal product is obtained.

[0049] (5) The hydrothermal reaction product obtained in step (4) is subjected to vacuum filtration, and the suction filtration is multiple suction filtration. Slowly add distilled water into the funnel during the first suction fil...

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Abstract

The invention provides a preparation method of monoclinic tungsten trioxide. WO4(2-) in soluble tungstate capable of ionizing WO4(2-) in a solution is combined to H+ in a salpeter solution, unstable weak electrolyte H2WO4 is formed in hydrothermal reaction, and then H2WO4 is prompted to be dehydrated to form tungsten oxide. The technology of the method is simple, and the method is convenient to operate and low in cost. The prepared tungsten trioxide is uniform in particle size distribution, high in purity, high in activity, good in reproducibility and good in quality stability, and crystalline grains are monoclinic, and are fully refined. The high-purity monoclinic tungsten oxide has huge application prospect and excellent and remarkable physicochemical property in the fields of photoelectrochemistry, catalytic degradation, gas sensors, thermochromic devices and the like. Therefore, the preparation method of the monoclinic tungsten trioxide has relatively large practical significance on production and application of the tungsten oxide, and is suitable for being popularized and used in the industry.

Description

technical field [0001] The invention relates to the technical field of preparation of tungsten oxide, in particular to a preparation method of monoclinic tungsten trioxide. Background technique [0002] As a typical transition metal element, tungsten can present a variety of different valence states due to its outer electron configuration: +2, +3, +4, +5, +6. Among them, WO 3 most stable. But since WO 3 The presence of oxygen vacancies in the structure, in WO 3 There may be several valence states coexisting, usually in WO 3-x（x=0~1） form exists. With the different oxygen content in the structure, the color will change, such as WO 3 is light yellow, W 20 o 58 (WO 2.9 ) for blue, W 18 o 49 (WO 2.7 ) for purple, WO 2 For tan etc. WO of the same valence 3 There are different crystal forms, the common ones are monoclinic, triclinic and hexagonal. Tungsten oxide with different phases and crystal forms has different characteristics in photoelectrochemistry, catalyti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G41/02B82Y40/00
CPCC01G41/02C01P2002/72C01P2004/03C01P2004/64
Inventor 潘昆明赵阳魏世忠单康宁杨璐朱甜媛蒋金林柳海斌何洪锋
Owner HENAN UNIV OF SCI & TECH
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