CN113184912A - Method for preparing hierarchical tungsten trioxide under assistance of microwaves - Google Patents

Method for preparing hierarchical tungsten trioxide under assistance of microwaves Download PDF

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CN113184912A
CN113184912A CN202110361907.0A CN202110361907A CN113184912A CN 113184912 A CN113184912 A CN 113184912A CN 202110361907 A CN202110361907 A CN 202110361907A CN 113184912 A CN113184912 A CN 113184912A
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microwave
tungsten trioxide
hierarchical
assisted
tungsten
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CN113184912B (en
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席晓丽
王建宇
刘阳思
聂祚仁
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Beijing University of Technology
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    • C01INORGANIC CHEMISTRY
    • C01GCOMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G41/00Compounds of tungsten
    • C01G41/02Oxides; Hydroxides
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    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/12Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
    • B01J19/122Incoherent waves
    • B01J19/126Microwaves
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2002/70Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2004/03Particle morphology depicted by an image obtained by SEM

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Abstract

The invention provides a method for preparing hierarchical tungsten trioxide by microwave assistance, which comprises the steps of obtaining a tungsten trioxide precursor by a microwave-assisted precipitation method, and calcining the tungsten trioxide precursor; in the microwave-assisted precipitation method, tungsten hexachloride and oxalic acid are dispersed in an organic solvent for reaction. The invention provides a microwave-assisted method for preparing hierarchical tungsten trioxide, which is characterized in that a tungsten trioxide precursor is obtained by adopting a microwave-assisted precipitation method and then calcined, so that the hierarchical tungsten trioxide can be conveniently and quickly obtained, and the method has low equipment requirement and high repeatability and is easier to popularize compared with other methods.

Description

Method for preparing hierarchical tungsten trioxide under assistance of microwaves
Technical Field
The invention relates to the technical field of preparation of nano materials, in particular to a method for preparing hierarchical tungsten trioxide by microwave assistance.
Background
Tungsten trioxide (WO)3) The N-type semiconductor metal oxide has the forbidden band width of 2.4-2.8 eV, can absorb most visible light, has high solar spectrum utilization rate, is easy to prepare due to abundant raw materials, and has the advantages of light corrosion resistance, good light stability, excellent electrochromism and photoluminescenceThe color change is of great concern, and the method has great application prospect in the fields of sensing devices, photoelectric energy storage materials, water pollution treatment and the like.
Compared with a block material, the nano tungsten trioxide material has some unique properties, such as excellent photocatalytic performance, excellent gas-sensitive response and the like. Therefore, the synthesis of nano tungsten trioxide materials of different morphologies, such as nanoparticles, nanotubes, nanowires, nanorods, nanosheets, nanoplates, hollow spheres and three-dimensional hierarchical structures, has been widely studied.
At present, the preparation methods of the nano tungsten trioxide material mainly comprise a sol-gel method, a hydrothermal method, a solvothermal method, a template method and the like. The whole preparation process of the sol-gel method needs longer time, which usually needs several days or weeks; the template method is complicated in post-treatment process, and template impurities may remain in the product; the hydrothermal method and the solvothermal method can be used for preparing nano tungsten trioxide materials with various shapes, but the whole preparation process is carried out under the conditions of high temperature and high pressure, and the requirement on equipment is high.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for preparing hierarchical tungsten trioxide by microwave assistance, which has the advantages of simple operation, short reaction time, low equipment requirement and high repeatability.
The invention adopts the following technical scheme:
the invention provides a method for preparing hierarchical tungsten trioxide by microwave assistance, which comprises the steps of obtaining a tungsten trioxide precursor by a microwave-assisted precipitation method, and calcining the tungsten trioxide precursor;
in the microwave-assisted precipitation method, tungsten hexachloride and oxalic acid are dispersed in an organic solvent for reaction.
The research of the invention finds that the tungsten trioxide with the hierarchical structure can be conveniently and quickly obtained by adopting a microwave-assisted precipitation method to obtain the tungsten trioxide precursor and then calcining the tungsten trioxide precursor, and the method has low requirement on equipment and high repeatability. Wherein, the microwave-assisted precipitation method needs to adopt tungsten hexachloride as a tungsten source to react with oxalic acid dispersed in an organic solvent, so as to obtain a relatively ideal product.
Preferably, the organic solvent is ethanol.
Preferably, the concentration of the tungsten hexachloride is 0.005-0.025mol/L, preferably 0.01mol/L, and the concentration of the shape control agent is 0.05-0.20mol/L, preferably 0.1 mol/L.
Further, the microwave-assisted precipitation method is characterized in that heating is performed at a constant microwave power.
Preferably, the microwave power is 300-600W, and the heating time is 30-60 min.
Further, the temperature for calcining the tungsten trioxide precursor is 400-550 ℃, preferably 500 ℃, and the temperature is kept for 1-6 hours.
In a specific embodiment of the invention, the microwave-assisted method for preparing hierarchical tungsten trioxide specifically comprises the following steps:
s1, dispersing tungsten hexachloride and oxalic acid in an organic solvent, and stirring in an air atmosphere to obtain a precursor solution;
s2, performing microwave heating on the precursor solution at normal temperature and normal pressure, wherein the reactor is externally connected with a condensation reflux device, the microwave power is 300-600W, and the heating time is 30-60 min;
s3, standing and cooling to room temperature after the reaction is finished, carrying out centrifugal separation on the reaction product, repeatedly washing and centrifuging the obtained solid substance by using an organic solvent, and drying for later use;
and S4, calcining the dried product, setting the temperature to be 500 ℃, preserving the heat for 1-6 h, taking out, placing in air, and cooling to room temperature to obtain the catalyst.
The invention also provides the tungsten trioxide with the hierarchical structure prepared by any one of the preparation methods.
The invention provides a microwave-assisted method for preparing hierarchical tungsten trioxide, which is characterized in that a tungsten trioxide precursor is obtained by adopting a microwave-assisted precipitation method and then calcined, so that the hierarchical tungsten trioxide can be conveniently and quickly obtained, and the method has low equipment requirement and high repeatability and is easier to popularize compared with other methods.
Drawings
FIG. 1 is an SEM photograph (magnification of 50000 times) of a hierarchical tungsten trioxide prepared in example 1 of the present invention;
FIG. 2 is an XRD pattern of hierarchical tungsten trioxide prepared in example 1 of the present invention;
FIG. 3 is an SEM photograph (magnification of 50000 times) of hierarchical tungsten trioxide prepared in example 2 of the present invention;
FIG. 4 is an XRD pattern of hierarchical tungsten trioxide prepared in example 2 of the present invention;
FIG. 5 is an SEM photograph (magnification of 50000 times) of hierarchical tungsten trioxide prepared in example 3 of the present invention;
FIG. 6 is an XRD pattern of hierarchical tungsten trioxide prepared in example 3 of the present invention;
FIG. 7 is an SEM photograph (magnification of 50000) of a product obtained in comparative example 1 of the present invention;
FIG. 8 is an SEM photograph (magnification of 50000) of a product obtained in comparative example 2 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Unless otherwise specified, the test reagents and materials used in the examples of the present invention are commercially available.
Unless otherwise specified, the technical means used in the examples of the present invention are conventional means well known to those skilled in the art.
Example 1
The embodiment provides a preparation method of tungsten trioxide with a hierarchical structure, which comprises the following specific steps:
0.397g of tungsten hexachloride and 1.261g of oxalic acid are weighed out and dissolved in 100ml of ethanol, and the solution is placed on a magnetic stirrer with the rotating speed of 350r/min and stirred for 30min under the air atmosphere to obtain a yellow solution. Transferring the solution to a three-neck flask, placing the three-neck flask in an XH-300UL computer microwave ultrasonic ultraviolet light combined catalytic synthesizer (only using the microwave function), externally connecting a condensation reflux device, setting the microwave power to be 500W, selecting a microwave power constant mode to heat for 45min, and naturally cooling to the room temperature after the reaction is finished. Centrifuging to obtain precipitate, washing with ethanol repeatedly, and centrifuging for 2 times at 3000r/min for 5 min. And (3) placing the cleaned product in an air drying box, setting the temperature to be 60 ℃, drying for 12h, taking out, placing in a muffle furnace, setting the temperature to be 500 ℃, preserving the heat for 1h, taking out, placing in air, and cooling to room temperature to obtain the tungsten trioxide with the hierarchical structure.
FIG. 1 is an SEM photograph of hierarchical tungsten trioxide prepared according to example 1, at a magnification of 50000, assembled from nanosheets; fig. 2 is an XRD spectrum of the hierarchical structure tungsten trioxide prepared in example 1, and it is found by comparison with a standard spectrum that the hierarchical structure tungsten trioxide prepared in example 1 of the present invention is monoclinic phase tungsten trioxide (PDF #72-0677) and has no other impurity phase.
Example 2
The embodiment provides a preparation method of tungsten trioxide with a hierarchical structure, which comprises the following specific steps:
0.397g of tungsten hexachloride and 1.261g of oxalic acid are weighed out and dissolved in 100ml of ethanol, and the solution is placed on a magnetic stirrer with the rotating speed of 350r/min and stirred for 30min under the air atmosphere to obtain a yellow solution. Transferring the solution to a three-neck flask, placing the three-neck flask in an XH-300UL computer microwave ultrasonic ultraviolet light combined catalytic synthesizer, externally connecting a condensation reflux device, setting the microwave power to be 450W, selecting a constant microwave power mode to heat for 50min, and naturally cooling to room temperature after the reaction is finished. Centrifuging to obtain precipitate, washing with ethanol repeatedly, and centrifuging for 2 times at 3000r/min for 5 min. And (3) placing the cleaned product in an air drying box, setting the temperature to be 60 ℃, drying for 12h, taking out, placing in a muffle furnace, setting the temperature to be 500 ℃, preserving the heat for 4h, taking out, placing in air, and cooling to room temperature to obtain the tungsten trioxide with the hierarchical structure.
FIG. 3 is an SEM photograph of the hierarchical structure tungsten trioxide prepared in example 2 at a magnification of 50000, which is assembled from nanosheets; fig. 4 is an XRD spectrum of the hierarchical structure tungsten trioxide prepared in example 2, and it is found by comparison with a standard spectrum that the hierarchical structure tungsten trioxide prepared in example 2 of the present invention is monoclinic phase tungsten trioxide (PDF #72-0677) and has no other impurity phase.
Example 3
The embodiment provides a preparation method of tungsten trioxide with a hierarchical structure, which comprises the following specific steps:
0.397g of tungsten hexachloride and 1.261g of oxalic acid are weighed out and dissolved in 100ml of ethanol, and the solution is placed on a magnetic stirrer with the rotating speed of 350r/min and stirred for 30min under the air atmosphere to obtain a yellow solution. Transferring the solution to a three-neck flask, placing the three-neck flask in an XH-300UL computer microwave ultrasonic ultraviolet light combined catalytic synthesizer, externally connecting a condensation reflux device, setting the microwave power to be 600W, selecting a microwave power constant mode to heat for 40min, and naturally cooling to room temperature after the reaction is finished. Centrifuging to obtain precipitate, washing with ethanol repeatedly, and centrifuging for 2 times at 3000r/min for 5 min. And (3) placing the cleaned product in an air drying box, setting the temperature to be 60 ℃, drying for 12h, taking out, placing in a muffle furnace, setting the temperature to be 500 ℃, preserving the heat for 6h, taking out, placing in air, and cooling to room temperature to obtain the tungsten trioxide with the hierarchical structure.
FIG. 5 is an SEM photograph of hierarchical tungsten trioxide prepared in example 3 at a magnification of 50000, assembled from nanosheets; fig. 6 is an XRD spectrum of the hierarchical structure tungsten trioxide prepared in example 3, and it is found by comparison with a standard spectrum that the hierarchical structure tungsten trioxide prepared in example 3 of the present invention is monoclinic phase tungsten trioxide (PDF #72-0677) and has no other impurity phase.
Comparative example 1
This comparative example provides a preparation process which differs from example 1 in that oxalic acid is replaced by an equimolar amount of urea.
As a result, the SEM image of the obtained product is shown in FIG. 7, which is 50000 times at magnification. From the SEM image, the product obtained by using urea as the shape control agent is irregular spherical in shape and is not self-assembled by nano sheets to form a hierarchical structure.
Comparative example 2
This comparative example provides a production method, which is different from example 2 in that the muffle furnace setting temperature was changed from 500 ℃ to 600 ℃.
As a result, the SEM image of the obtained product is shown in FIG. 8, which is 50000 times magnification. As can be seen from the SEM image, after the calcination temperature is raised to 600 ℃, the obtained product has irregular appearance and is not a hierarchical structure formed by self-assembly of nano sheets.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (9)

1. A method for preparing hierarchical tungsten trioxide by microwave assistance is characterized by comprising the steps of obtaining a tungsten trioxide precursor by a microwave-assisted precipitation method, and calcining the tungsten trioxide precursor;
in the microwave-assisted precipitation method, tungsten hexachloride and oxalic acid are dispersed in an organic solvent for reaction.
2. The microwave-assisted method for preparing hierarchical tungsten trioxide according to claim 1, wherein the organic solvent is ethanol.
3. The microwave-assisted preparation method of hierarchical tungsten trioxide according to claim 1 or 2, characterized in that the concentration of the tungsten hexachloride is 0.005-0.025mol/L and the concentration of the oxalic acid is 0.05-0.20 mol/L.
4. The microwave-assisted preparation method of hierarchical tungsten trioxide according to claim 3, characterized in that the concentration of the tungsten hexachloride is 0.01mol/L and the concentration of the oxalic acid is 0.1 mol/L.
5. The microwave-assisted method for preparing hierarchical tungsten trioxide according to any one of claims 1 to 4, wherein the microwave-assisted precipitation method is characterized in that heating is performed at a constant microwave power.
6. The microwave-assisted preparation method of hierarchical tungsten trioxide according to claim 5, wherein the microwave power is 300-600W, and the heating time is 30-60 min.
7. The microwave-assisted preparation method of hierarchical tungsten trioxide according to any one of claims 1 to 6, characterized in that the calcination temperature is 400 to 550 ℃, preferably 500 ℃, and the temperature is kept for 1 to 6 hours.
8. The microwave-assisted preparation method of hierarchical tungsten trioxide according to any one of claims 1 to 7, characterized in that the method comprises the following steps:
s1, dispersing tungsten hexachloride and oxalic acid in an organic solvent, and stirring in an air atmosphere to obtain a precursor solution;
s2, performing microwave heating on the precursor solution at normal temperature and normal pressure, wherein the reactor is externally connected with a condensation reflux device, the microwave power is 300-600W, and the heating time is 30-60 min;
s3, standing and cooling to room temperature after the reaction is finished, carrying out centrifugal separation on the reaction product, repeatedly washing and centrifuging the obtained solid substance by using an organic solvent, and drying for later use;
and S4, calcining the dried product, setting the temperature to be 500 ℃, preserving the heat for 1-6 h, taking out, placing in air, and cooling to room temperature to obtain the catalyst.
9. Tungsten trioxide having a hierarchical structure produced by the production method according to any one of claims 1 to 8.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102757095A (en) * 2011-04-29 2012-10-31 北京化工大学 Tungsten oxide nanoflake self-assembly nanosphere and application method and application of tungsten oxide nanoflake self-assembly nanosphere
CN105271419A (en) * 2015-09-30 2016-01-27 南京理工大学 Preparation method of tungstic oxide nanosheet self-assembled micro-nano flower-balls
CN107117831A (en) * 2017-05-26 2017-09-01 桂林理工大学 A kind of WO3The preparation method of nano-chip arrays
CN108083341A (en) * 2018-01-30 2018-05-29 陕西科技大学 A kind of preparation method of the monoclinic phase tungstic acid with Lacking oxygen
JP2019142760A (en) * 2018-02-16 2019-08-29 住友金属鉱山株式会社 Method for producing tungsten trioxide

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102757095A (en) * 2011-04-29 2012-10-31 北京化工大学 Tungsten oxide nanoflake self-assembly nanosphere and application method and application of tungsten oxide nanoflake self-assembly nanosphere
CN105271419A (en) * 2015-09-30 2016-01-27 南京理工大学 Preparation method of tungstic oxide nanosheet self-assembled micro-nano flower-balls
CN107117831A (en) * 2017-05-26 2017-09-01 桂林理工大学 A kind of WO3The preparation method of nano-chip arrays
CN108083341A (en) * 2018-01-30 2018-05-29 陕西科技大学 A kind of preparation method of the monoclinic phase tungstic acid with Lacking oxygen
JP2019142760A (en) * 2018-02-16 2019-08-29 住友金属鉱山株式会社 Method for producing tungsten trioxide

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Title
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孙墨杰 等: "分级结构WO3的制备及对SF6分解产物H2S的检测", 《微纳电子技术》 *

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