Method for preparing tungsten trioxide crystals with controllable growth of crystal surfaces

A technology of tungsten trioxide and crystal, which is applied in the field of preparation of tungsten trioxide crystal plane controlled growth, to achieve the effect of uniform appearance, controllable ratio of exposed crystal plane, and controllable particle size

Active Publication Date: 2012-10-10
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a preparation method for the controllable growth of tungsten trioxide crystal planes, which can solve the problem of providing tungsten trioxide photocatalysts with different redox abilities for different reaction systems, and can prepare tungsten trioxide photocatalysts with different morphology. Regular tungsten trioxide crystals with some crystal faces exposed

Method used

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  • Method for preparing tungsten trioxide crystals with controllable growth of crystal surfaces
  • Method for preparing tungsten trioxide crystals with controllable growth of crystal surfaces
  • Method for preparing tungsten trioxide crystals with controllable growth of crystal surfaces

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Weigh 150 mg of commercial tungsten boride powder without any treatment (in this embodiment, the size of tungsten boride powder is 800nm, chemical formula WB x , x=1), put it into a 80mL stainless steel reaction kettle lined with polytetrafluoroethylene, which is equipped with 8mL of 2M hydrofluoric acid water and ethanol mixed solution (the volume ratio of water and ethanol is 3:4) . After the reactor was sealed, put it into an oven and heat it at 190°C for 36 hours, take out the reaction sample, wash it with deionized water and dry it at 80°C to obtain hydrogen tungsten bronze (H 0.23 WO 3 ) crystals, and heat treatment in air at 700°C for 2 hours to obtain tungsten trioxide crystals with equal proportions of three crystal planes.

[0031] Such as figure 1 As shown in (a), (b), (c), and (d), the hydrothermally formed hydrogen tungsten bronze crystals have a complete cubic morphology, and the particle size is 2000nm. The tungsten trioxide crystal obtained after hea...

Embodiment 2

[0036] Weigh 100 mg of commercial tungsten boride powder without any treatment (in this embodiment, the size of tungsten boride powder is 800nm, chemical formula WB x , x=1), put it into a 22mL 2M hydrofluoric acid water-ethanol mixed solution (the volume ratio of water and ethanol is 1:1), and take polytetrafluoroethylene as the inner liner 80mL stainless steel reaction kettle . After the reaction kettle is sealed, put it in an oven and heat it at 190°C for 24 hours, take out the reaction sample, wash it with deionized water and dry it at 80°C, and then heat it in air at 700°C for 2 hours to get the three oxides with equal crystal plane ratios. Tungsten crystals.

[0037] Such as Figure 6 As shown in (a), the tungsten trioxide crystal synthesized under this condition has a complete cubic shape, and the particle size is 1000nm.

Embodiment 3

[0039] Weigh 300 mg of commercial tungsten boride powder without any treatment (in this embodiment, the size of tungsten boride powder is 800nm, chemical formula WB x , x=1), put it into a 22mL 2M hydrofluoric acid water-ethanol mixed solution (the volume ratio of water and ethanol is 1:1), and take polytetrafluoroethylene as the inner liner 80mL stainless steel reaction kettle . After the reaction kettle is sealed, put it in an oven and heat it at 190°C for 24 hours, take out the reaction sample, wash it with deionized water and dry it at 80°C, and then heat it in air at 700°C for 2 hours to get the three oxides with equal crystal plane ratios. Tungsten crystals.

[0040] Such as Figure 6 As shown in (b), the tungsten trioxide crystals synthesized under this condition have some agglomerations, so that the formed cubes cross each other, and the size of the particles is 2000nm.

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Abstract

The invention, relating to the field of tungsten trioxide crystals, concretely discloses a method for preparing tungsten trioxide crystals with controllable growth of the crystal surfaces. The method is characterized by using tungsten boride as a precursor by wet chemical process and carrying out hydrothermal growth of the crystal surfaces to expose tungsten trioxide crystals with different proportions, so that the problem of providing tungsten trioxide catalysts with different redox abilities for different reaction systems can be solved; putting the precursor in a reaction vessel filled with an aqueous nitric acid solution, and carrying out heat treatment to obtain crystal surface-dominated tungsten trioxide crystals {002}; putting the precursor in a reaction vessel filled with a hydrofluoric acid solution or a hydrofluoric acid ethanol solution or a mixed solution of aqueous hydrofluoric acid and ethanol, carrying out heat treatment to obtain cubic hydrogen tungsten bronze crystals, and heating the hydrogen tungsten bronze crystals in air to obtain tungsten trioxide crystals with identical crystal surface proportion {002}, {200}, {020}. According to the invention, tungsten trioxide crystals with regular morphology, different crystal surface proportions, and good ability of oxygen production by water splitting can be prepared.

Description

technical field [0001] The invention relates to the field of tungsten trioxide crystals, in particular to a preparation method for the controllable growth of crystal planes of tungsten trioxide crystals, which uses tungsten boride as a precursor to hydrothermally grow tungsten trioxide crystals with different proportions of crystal planes through a wet chemical process. Background technique [0002] Because tungsten trioxide has a suitable band gap (2.5-2.8eV), high acid resistance and high thermal stability, it has attracted extensive attention and in-depth research as an n-type semiconductor material. Tungsten trioxide photocatalysts are widely used in photodegradation, solar cells, photoelectrochemistry, photochromism, and gas sensors in addition to photocatalytic water splitting. Because photocatalytic reactions are mainly carried out on the surface of semiconductor materials, it is the focus of research in recent years to find ways to improve their photocatalytic effici...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/16C30B7/10
Inventor 刘岗谢英鹏成会明
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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