Preparation method of two-dimensional round-corner square hypoxic tungsten oxide
Through the microwave hydrothermal reaction method, the molar ratio of reactants and stirring conditions are adjusted to prepare two-dimensional rounded square oxide-deficient tungsten, which solves the problems of difficult morphology control and complicated process in the existing technology, and realizes the development of high-performance materials. Preparation and cost reduction.
Patent Information
- Application Number
- CN202411172383.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2025-01-21
AI Technical Summary
The prior art is difficult to accurately control the microstructure of tungsten oxide materials, especially to prepare two-dimensional materials with specific geometric shapes, and the process is complex and costly, resulting in poor performance.
Using a microwave hydrothermal reaction method, using WCl6 and thiourea as reactants, by adjusting the molar ratio and stirring conditions of the reactants, combined with a mixed solvent of water and DMF, and controlling the crystal growth direction and speed, a two-dimensional rounded square defect was prepared. Tungsten oxide.
It has achieved efficient preparation of oxide-deficient tungsten materials with precise rounded square structures, improving its performance in optoelectronic devices and other applications. Compared with traditional methods, microwave hydrothermal technology has the advantages of simple operation and low cost.
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Figure CN119330401A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of transition metal oxides, and in particular to a method for preparing a two-dimensional rounded square oxide-deficient tungsten. Background Art
[0002] Transition metal oxides are an important class of materials that consist of transition metals (located in the d-block of the periodic table) and oxygen. These materials have a wide range of physical and chemical properties, which are mainly attributed to the different filling states of transition metal d-orbital electrons and the interaction between these electrons and oxygen atoms.
[0003] Tungsten oxide is usually expressed as WO x , where the x value is less than 3, indicating that its oxygen content is lower than that of tungsten trioxide (WO3) at the stoichiometric ratio. At the same time, oxygen-deficient tungsten compounds usually exhibit semiconductor or metal-like conductivity. As the oxygen content decreases, its resistivity may decrease significantly. This is because oxygen vacancies can act as electron traps or provide additional carriers. At the same time, oxygen-deficient tungsten compounds have unique optical properties, such as wide spectrum absorption capability, which can absorb light in the visible light and even near-infrared light region.
[0004] However, in the actual production process, there are the following problems: 1. Difficulty in morphology control: At present, it is difficult to accurately control the microstructure when preparing tungsten oxide materials, especially the preparation of two-dimensional materials with specific geometric shapes (such as rounded squares); 2. Complex process: Existing preparation methods often require complex equipment and strict condition control, resulting in high costs and difficulty in large-scale production; 3. Limited performance: Due to the irregularity of the morphology, the performance of tungsten oxide materials obtained by traditional preparation methods is not ideal in some applications. Summary of the invention
[0005] In order to solve the above problems, the present invention aims to develop a new preparation method, which can efficiently prepare oxide-deficient tungsten materials with precise rounded square structures to improve their performance in optoelectronic devices and other applications.
[0006] The present invention provides a preparation method of a two-dimensional rounded square tungsten oxide-deficient material. The preparation method specifically comprises the following steps: placing WCl6 and thiourea in a reactor, adding a mixed solvent and stirring, performing a microwave hydrothermal reaction after the stirring, naturally cooling to room temperature after the microwave hydrothermal reaction, and then performing a centrifugal treatment, washing the sample with a first solvent and a second solvent in turn, and then drying to obtain a two-dimensional rounded square tungsten oxide-deficient material.
[0007] Compared with the prior art, the present invention designs a new synthesis method based on microwave hydrothermal, and obtains a two-dimensional rounded square tungsten oxide-deficient morphology, which is conducive to broadening the application prospects of tungsten oxide-deficient. At the same time, compared with the traditional oven hydrothermal synthesis method, microwave hydrothermal has the advantages of simple operation, safety and speed, directional control, and low cost.
[0008] In some embodiments, the molar ratio of WCl6 to thiourea is 1:(5-20).
[0009] Compared with the prior art, the present invention uses WCl6 and thiourea as reactants, wherein WCl6 is used as a precursor, thiourea is used as a reducing agent, and the above-mentioned molar ratio range is used. Thiourea is used as a reducing agent and a template agent, and plays a key role in the reaction process. By adjusting the ratio of WCl6 to thiourea, the morphology of the final product can be affected. The concentration of thiourea at different ratios can affect the nucleation rate and growth direction during the crystallization process, thereby affecting the morphology of the product; the presence of thiourea can regulate the direction and speed of crystal growth, thereby controlling the size of the final product. A higher thiourea ratio may result in a smaller particle size, while a lower ratio may produce larger particles.
[0010] In some embodiments, the mixed solvent consists of water and DMF in a volume ratio of 1:1.
[0011] Compared with the prior art, the present invention adopts the above-mentioned mixed solvent, wherein DMF is a polar aprotic solvent, which has good dissolving power and can dissolve a variety of inorganic salts and organic compounds, and water is also a polar solvent, but compared with DMF, water has a stronger hydrogen bond forming ability. Mixing these two solvents can provide an environment that has both strong polarity and can interact with a variety of substances.
[0012] In some embodiments, the stirring time is 0.5-3 h, and the stirring speed is 600 r / min.
[0013] Compared with the prior art, the present invention adopts the above-mentioned stirring time and stirring speed. By controlling the stirring time and speed, it can ensure that the reactants are evenly distributed during the reaction, thereby improving the uniformity and controllability of the reaction. At the same time, appropriate stirring conditions help to control the morphology of the product, which is crucial for preparing oxide-deficient tungsten materials with specific morphology.
[0014] In some embodiments, the parameters of the microwave hydrothermal reaction are as follows: temperature is 220° C., and time is 60-300 min.
[0015] Compared with the prior art, the present invention adopts the above-mentioned microwave hydrothermal reaction parameters, which has the following functions: by setting the temperature of the microwave hydrothermal reaction to 220°C and the time to between 60-300 minutes, the morphology and size of the product can be effectively controlled, and the yield and purity of the product can be improved. The selection of these parameters is crucial for the preparation of a two-dimensional rounded square tungsten oxide-deficient material with a specific morphology.
[0016] In some embodiments, the first solvent is water, the second solvent is DMF, and the sample is washed three times.
[0017] Compared with the prior art, the present invention adopts the above-mentioned washing parameters and can effectively remove by-products and other impurities generated during the reaction process through multiple washings. At the same time, washing can improve the purity of the final product and reduce the difficulty of subsequent treatment.
[0018] In some embodiments, the drying temperature is 60° C. and the drying time is 12-24 hours.
[0019] Compared with the prior art, the present invention adopts the above-mentioned drying parameters, by setting the drying temperature to 60°C and the drying time to 12-24 hours, which can effectively remove the residual solvent in the washing process and ensure the product is dry. The selection of these parameters is crucial to maintaining the morphology of the product and improving its stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a SEM image of the two-dimensional rounded square oxide-deficient tungsten prepared in Example 1;
[0021] Figure 2 The XRD pattern of the two-dimensional rounded square oxide-deficient tungsten prepared in Example 1;
[0022] Figure 3 This is the EPR image of the two-dimensional rounded square oxide-deficient tungsten prepared in Example 1. DETAILED DESCRIPTION
[0023] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the scope of protection of the claims of the present invention.
[0024] It should be noted that the endpoints and any values of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.
[0025] Unless otherwise defined, all terms, symbols and other scientific terms used herein are intended to have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. In some cases, terms with conventionally understood meanings are defined herein for the purpose of clarification or ease of reference, and such definitions herein should not be construed as indicating significant differences from conventional understandings in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents and instruments is carried out in accordance with the protocols and parameters given by the manufacturer.
[0026] The technical effects of the present invention are described below in conjunction with specific embodiments.
[0027] Example 1
[0028] The present embodiment provides a preparation method of oxide-deficient tungsten, and the specific steps are as follows: weigh 1mmol of WCl6 and 10mmol of thiourea in a 100ml beaker, add water and DMF in a volume ratio of 1:1, the total volume of the liquid is 40-80ml, add a stirring bar, stir vigorously for 2h, transfer to a microwave hydrothermal reactor after stirring for microwave hydrothermal, gradually heat up to 220 degrees, keep at 220 degrees for 180 minutes, wait for the temperature to drop completely, wash the sample with water and DMF by centrifugation for 3 times respectively, dry at 60 degrees overnight after washing is complete, and obtain a two-dimensional rounded square oxide-deficient tungsten.
[0029] Example 2
[0030] The present embodiment provides a preparation method of oxide-deficient tungsten, and the specific steps are as follows: weigh 1mmol of WCl6 and 5mmol of thiourea in a 100ml beaker, add water and DMF in a volume ratio of 1:1, the total volume of the liquid is 40-80ml, add a stirring bar, stir vigorously for 0.5h, transfer to a microwave hydrothermal reactor after stirring for microwave hydrothermal, gradually heat to 220 degrees, keep at 220 degrees for 60 minutes, wait for the temperature to drop completely, wash the sample with water and DMF by centrifugation for 2-3 times respectively, dry at 60 degrees overnight after washing is complete, and obtain a two-dimensional rounded square oxide-deficient tungsten.
[0031] Example 3
[0032] The present embodiment provides a preparation method of oxide-deficient tungsten, and the specific steps are as follows: weigh 1mmol of WCl6 and 8mmol of thiourea in a 100ml beaker, add water and DMF in a volume ratio of 1:1, the total volume of the liquid is 40-80ml, add a stirring bar, stir vigorously for 1h, transfer to a microwave hydrothermal reactor after stirring for microwave hydrothermal, gradually heat up to 220 degrees, keep at 220 degrees for 120 minutes, wait for the temperature to drop completely, wash the sample with water and DMF by centrifugation for 3 times respectively, dry at 60 degrees overnight after washing is complete, and obtain a two-dimensional rounded square oxide-deficient tungsten.
[0033] Example 4
[0034] The present embodiment provides a preparation method of oxide-deficient tungsten, and the specific steps are as follows: weigh 1mmol of WCl6 and 15mmol of thiourea in a 100ml beaker, add water and DMF in a volume ratio of 1:1, the total volume of the liquid is 40-80ml, add a stirring bar, stir vigorously for 2.5h, transfer to a microwave hydrothermal reactor after stirring for microwave hydrothermal, gradually heat to 220 degrees, keep at 220 degrees for 240 minutes, wait for complete cooling, wash the sample with water and DMF respectively by centrifugation for 3 times, dry at 60 degrees overnight after washing, and obtain a two-dimensional rounded square oxide-deficient tungsten.
[0035] Example 5
[0036] This embodiment provides a preparation method of oxide-deficient tungsten, and the specific steps are as follows: weigh 1mmol of WCl6 and 20mmol of thiourea in a 100ml beaker, add water and DMF in a volume ratio of 1:1, the total volume of the liquid is 40-80ml, add a stirring bar, stir vigorously for 3h, transfer to a microwave hydrothermal reactor after stirring for microwave hydrothermal, gradually heat to 220 degrees, keep at 220 degrees for 300 minutes, wait for the temperature to drop completely, wash the sample with water and DMF by centrifugation for 3 times respectively, and dry at 60 degrees overnight after washing to obtain a two-dimensional rounded square oxide-deficient tungsten.
[0037] The product obtained in Example 1 was tested for performance. The test results are as follows: Figure 1 , Figure 2 and Figure 3 As shown, Figure 1 This is a SEM image of the oxide-deficient tungsten obtained in Example 1. Figure 2 is the XRD pattern of the oxide-deficient tungsten obtained in Example 1, Figure 3 The EPR diagram of the oxide-deficient tungsten obtained in Example 1 is shown in FIG. Figure 1 and Figure 2 It can be seen that the method of the present invention can not only successfully prepare oxide-deficient tungsten, but also the obtained oxide-deficient tungsten has a two-dimensional rounded square morphology, which is different from the nanoflower morphology and regular hexagonal morphology obtained by the traditional synthesis method. Figure 3It can be seen that there are two centrally symmetrical peaks near g = 2, indicating that there are oxygen atom vacancies in the material, and the material is not WO3 but a tungsten oxide-deficient WO X (x<3).
[0038] It can be seen from the above results that the present invention designs a new synthesis method based on microwave hydrothermal, and obtains a two-dimensional rounded square tungsten oxide-deficient morphology, which is beneficial to broadening the application prospects of tungsten oxide-deficient. At the same time, compared with the traditional oven hydrothermal synthesis method, microwave hydrothermal has the advantages of simple operation, safety and speed, directional control, and low cost.
[0039] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.
Claims
1. A method for preparing a two-dimensional rounded square oxide-deficient tungsten, characterized in that: The preparation method specifically includes the following steps: placing WCl6 and thiourea in a reactor, adding a mixed solvent and stirring, performing a microwave hydrothermal reaction after the stirring, naturally cooling to room temperature after the microwave hydrothermal reaction, and then centrifuging, washing the sample with a first solvent and a second solvent in turn, and then drying to obtain a two-dimensional rounded square oxide-deficient tungsten.
2. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The molar ratio of WCl6 to thiourea is 1:(5-20).
3. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The mixed solvent consists of water and DMF in a volume ratio of 1:
1.
4. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The stirring time is 0.5-3h, and the stirring speed is 600r / min.
5. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The parameters of the microwave hydrothermal reaction are as follows: temperature is 220°C and time is 60-300 min.
6. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The first solvent is water, the second solvent is DMF, and the number of times of washing the samples is 3 times.
7. The method for preparing the two-dimensional rounded square oxide-deficient tungsten according to claim 1, characterized in that: The drying temperature is 60°C and the drying time is 12-24 hours.