A two-dimensional Cr2Se3 nanomaterial, its preparation method and application
The preparation of a hexagonal phase two-dimensional Cr2Se3 nanomaterial by solvent thermal method solves the problems of high energy consumption and uneven morphology in the prior art, and achieves efficient photocatalytic degradation of dye pollutants in water bodies, improving the light absorption and catalytic performance of the material.
Patent Information
- Application Number
- CN202510165290.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-14
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2045-02-14
AI Technical Summary
The existing high-temperature solid-phase reaction method synthesizes Cr2Se3 materials with high energy consumption and long time, and the product size is uncontrollable and the morphology is uneven, which limits its application and industrial development in micro/nano devices.
Two-dimensional Cr2Se3 nanomaterials were prepared by solvothermal method, and solvent-thermal reaction was carried out in a high-boiling reaction medium by dissolving chromium source and selenium source. The reaction conditions were controlled to obtain the crystal structure and nanosheet-like morphology of the hexagonal phase, avoid agglomeration, and a multi-stage structure was formed through self-assembly to improve the specific surface area and light absorption capacity.
The prepared two-dimensional Cr2Se3 nanomaterial has high crystallinity and polygonal sheet-like structure, self-assembled to form a multi-stage structure, improves light absorption capacity and catalytic activity, and effectively degrades dye pollutants such as methylene blue in water.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of functional nanomaterials, and in particular relates to a two-dimensional Cr2Se3 nanomaterial, a preparation method of the nanomaterial, and an application of the nanomaterial as a photocatalytic degradation material. Background Art
[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.
[0003] Two-dimensional nanomaterials, with their tunable optical, electrical, and thermal properties, structural variability, and thickness-dependent ferromagnetism and antiferromagnetism, hold great promise for applications in clean energy conversion, sensors, and information storage. Among these materials, chromium-based selenides, due to their diverse crystal structures and elemental compositions, have sparked widespread research in the fields of photoelectric and thermoelectric conversion, environmental pollution purification, information storage, and magnetic sensing.
[0004] Currently, studies have reported the preparation of Cr2Se3 using a high-temperature solid-phase reaction method, where chromium and selenium powders are mixed, heated to 1000°C for two days, and then at 250°C for seven days. However, this high-temperature solid-phase reaction method for synthesizing Cr2Se3 is not only energy-intensive and time-consuming, but also often exhibits uncontrollable size and non-uniform morphology. Consequently, this significantly impacts or limits the performance of Cr2Se3, its application in micro- and nanodevices, and its industrial development. Summary of the Invention
[0005] To address the problems existing in the prior art, the present invention provides a two-dimensional sheet-like Cr2Se3 nanomaterial with a hexagonal phase, high crystallinity, excellent light absorption capacity and stable performance, and a simple preparation method. Based on the above technical achievements, the present invention provides the following solutions:
[0006] In the first aspect of the present invention, a two-dimensional Cr2Se3 nanomaterial is provided, which is a hexagonal crystal. The main diffraction peaks in its XRD diffraction pattern are located at 30.8±0.1°, 32.6±0.1°, 42.6±0.1°, 50.7±0.1°, 56.1±0.1°, 61.7±0.1°, and 64.3±0.1°, respectively; the microscopic morphology is nano-scale flakes with a thickness of 2~5nm and a side length of 20~100nm.
[0007] Through transmission electron microscopy observation, the above-mentioned Cr2Se3 nanomaterials are hexagonal or polygonal sheet materials. The advantage of this configuration is that the crystals are less likely to agglomerate during the preparation and crystal growth of the nanomaterials, and the sheet-like nanomaterials can easily form a multi-level spatial structure through self-assembly, thereby increasing the specific surface area.
[0008] In a second aspect, the present invention provides a method for preparing the two-dimensional Cr2Se3 nanomaterial according to the first aspect, comprising the following steps:
[0009] The method comprises adding a soluble chromium source and a selenium source into a high-boiling-point reaction medium to carry out a solvent thermal reaction, and separating a solid reaction product to obtain the product.
[0010] In the above-mentioned solvothermal reaction system, the molar ratio of the Cr:Se elements should be close to 2:3, wherein the Se element can be appropriately excessive, and therefore, the preferred ratio is 1:1.5-3.
[0011] The above-mentioned soluble chromium source and selenium source are substances that are soluble in the reaction medium and can dissociate into chromium ions and selenium ions, including organic and inorganic compounds; feasible chromium sources include but are not limited to one or a combination of chromium acetylacetonate, chromium trichloride, chromium nitrate or chromium acetate; feasible selenium sources are one or a combination of diphenyl diselenide, dibenzyl diselenide, selenium dioxide or selenium powder.
[0012] In one embodiment provided by the present invention, the chromium source is chromium acetylacetonate, and the selenium source is diphenyl diselenide.
[0013] In another feasible embodiment, the chromium source is chromium acetate, and the selenium source is diphenyl diselenide.
[0014] In another feasible embodiment, the chromium source is chromium trichloride, and the selenium source is diphenyl diselenide.
[0015] The high-boiling-point reaction medium is selected from one or a combination of organic amines, oleic acid, and octadecene, wherein the organic amine is selected from one or more of oleylamine, octadecylamine, or hexadecylamine; further, the high-boiling-point reaction medium is a mixture of organic amines and oleic acid in a volume ratio of 1 to 7:1.
[0016] The solvothermal reaction comprises a first and second stage. In the first stage, the chromium and selenium sources are added to the reaction medium under an inert gas atmosphere, followed by heating to 130-180°C for 30-90 minutes. This heating dissolves the chromium and selenium sources and removes oxygen, moisture, and low-boiling impurities from the reaction system. In the second stage, the reaction system is further heated at a temperature between 260-350°C for a reaction time of 5-180 minutes. After the solvothermal reaction is complete, the solid product is separated from the reaction solution by centrifugation or filtration, and then washed with an organic reagent, such as anhydrous ethanol and / or cyclohexane, to obtain the desired product.
[0017] This two-dimensional Cr2Se3 nanomaterial has a self-assembled, multi-level structure. Compared to existing Cr2Se3 materials, it provides a larger specific surface area and more active reaction sites, which helps improve electron transport in catalytic reactions. The polygonal flakes self-assemble in space, increasing the absorption of light from different directions and enhancing the material's light absorption capacity. The present invention has demonstrated that under illumination, this nanomaterial has excellent ability to degrade methylene blue in aqueous environments.
[0018] Therefore, the third aspect of the present invention is the use of the two-dimensional Cr2Se3 nanomaterial described in the first aspect as a photocatalytic degradation material.
[0019] Furthermore, the application is the degradation of dye pollutants in aquatic environments, such as natural environments such as rivers, lakes, and seas, as well as industrial and domestic water such as drinking water and treated sewage. The dyes include methyl blue, methylene blue, Sudan red, and the like.
[0020] In a fourth aspect, the present invention provides a method for degrading methylene blue in an aqueous environment, comprising dispersing the two-dimensional Cr2Se3 nanomaterial described in the first aspect into the aqueous environment to be treated.
[0021] The steps of the above-mentioned degradation method are as follows: the two-dimensional Cr2Se3 nanomaterial described in the first aspect is surface-modified with mercaptopropionic acid to enhance its water solubility; the treated nanomaterial is dispersed into the water environment to be treated, dissolved by stirring, and then irradiated with light for a period of time.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The Cr2Se3 nanomaterial synthesized by the present method exhibits a hexagonal phase, high crystallinity, and a hexagonal or polygonal lamellae morphology. The two-dimensional Cr2Se3 nanomaterial and its self-assembled hierarchical structure can absorb scattered or reflected incident light multiple times, thereby enhancing the material's light absorption capacity.
[0024] 2. The two-dimensional Cr2Se3 nanomaterials are polygonal sheets and can self-assemble to form a multi-level structure, which not only provides a larger specific surface area and accelerates mass transfer and electron transport during the catalytic reaction, but also effectively avoids the problem of easy stacking and agglomeration between nanomaterials.
[0025] 3 Hexagonal Cr2Se3 is a non-layered crystal structure with a two-dimensional morphology, which can provide abundant catalytic active sites due to the presence of surface dangling bonds.
[0026] 4. While exploring the light absorption properties of the Cr2Se3 nanomaterial, the present inventors also discovered that the nanomaterial has excellent degradation capabilities for methylene blue dye. Based on these properties, the nanomaterial can also be used as a photocatalyst to degrade dye pollutants in aquatic environments. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.
[0028] Figure 1 This is the X-ray diffraction pattern (XRD) of the target product in Example 1.
[0029] Figure 2 This is a transmission electron microscope (TEM) photograph of the target product of Example 1.
[0030] Figure 3 This is the ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectrum of the target product in Example 1.
[0031] Figure 4 This is a graph showing the photocatalytic degradation of methylene blue by the target product of Example 1.
[0032] Figure 5 This is the X-ray diffraction pattern (XRD) of the target product of Example 2.
[0033] Figure 6 This is a transmission electron microscope (TEM) photograph of the target product of Example 3.
[0034] Figure 7 This is the X-ray diffraction pattern (XRD) of the target product of Example 4. DETAILED DESCRIPTION
[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.
[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.
[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.
[0038] Example 1
[0039] In this embodiment, a two-dimensional Cr2Se3 nanomaterial is provided, and its preparation method is as follows:
[0040] (1) In a 100 ml three-necked flask, add 0.2 mmol of chromium acetylacetonate, 0.3 mmol of diphenyl diselenide, 4.0 ml of oleylamine and 4.0 ml of oleic acid to obtain a mixed solution.
[0041] (2) Nitrogen was introduced into the three-necked flask in step (1), and the mixture was heated to 130°C under magnetic stirring for 90 minutes to remove moisture and low-boiling-point impurities in the reaction system.
[0042] (3) The mixed solution was heated to 320°C for 30 minutes. After the reaction was completed, the mixture was cooled to room temperature and the solid product in the reaction solution was separated by centrifugation. The solid product was then washed three times by centrifugation with cyclohexane and anhydrous ethanol respectively. The obtained solid product was the target product.
[0043] Example 2
[0044] In this embodiment, another two-dimensional Cr2Se3 nanomaterial is provided, and its preparation method is as follows:
[0045] (1) In a 100 ml three-necked flask, add 0.2 mmol of chromium acetylacetonate, 0.3 mmol of diphenyl diselenide, 6.0 ml of oleylamine and 2.0 ml of oleic acid to obtain a mixed solution.
[0046] (2) Nitrogen was introduced into the three-necked flask in step (1), and the mixture was heated to 180°C under magnetic stirring and kept warm for 30 minutes to remove moisture and low-boiling-point impurities in the reaction system.
[0047] (3) The mixed solution was heated to 260°C for 180 minutes. After the reaction was completed, the mixture was cooled to room temperature and the solid product in the reaction solution was separated by centrifugation. The solid product was then washed three times by centrifugation with cyclohexane and anhydrous ethanol respectively. The obtained solid product was the target product.
[0048] Example 3
[0049] In this embodiment, another two-dimensional Cr2Se3 nanomaterial is provided, and its preparation method is as follows:
[0050] (1) In a 100 ml three-necked flask, add 0.2 mmol of chromium acetylacetonate, 0.3 mmol of diphenyl diselenide, 7.0 ml of oleylamine and 1.0 ml of oleic acid to obtain a mixed solution.
[0051] (2) Nitrogen was introduced into the three-necked flask in step (1), and the mixture was heated to 160°C under magnetic stirring for 60 minutes to remove moisture and low-boiling impurities in the reaction system.
[0052] (3) The mixed solution was heated to 350°C for 15 minutes. After the reaction was completed, the mixture was cooled to room temperature and the solid product in the reaction solution was separated by centrifugation. The solid product was then washed three times by centrifugation with cyclohexane and anhydrous ethanol respectively. The obtained solid product was the target product.
[0053] Example 4
[0054] This embodiment provides another two-dimensional Cr2Se3 nanomaterial. The difference from Example 1 is that step (1) is performed as follows: 0.2 mmol of chromium acetate, 0.3 mmol of dibenzyl diselenide, 6.0 ml of octadecylamine, and 2.0 ml of oleic acid are added to a 100 ml three-necked flask to obtain a mixed solution. The remaining settings are the same as those in Example 1.
[0055] Example 5
[0056] This embodiment provides another two-dimensional Cr2Se3 nanomaterial. The difference from Example 1 is that step (1) is performed as follows: 0.2 mmol of chromium trichloride, 0.3 mmol of dibenzyl diselenide, 6.0 ml of hexadecylamine, and 2.0 ml of oleic acid are added to a 100 ml three-necked flask to obtain a mixed solution. The remaining settings are the same as those in Example 1.
[0057] Composition, structure characterization and performance testing
[0058] Figure 1This is the X-ray diffraction pattern of the target product obtained in Example 1. As can be seen from the figure: all diffraction peaks are good indicators of the corresponding crystal planes in Cr2Se3 (JCPDS Card No. 40-1404), and no other impurity peaks appear, indicating that the target product prepared in this example is a hexagonal Cr2Se3 crystal. Similarly, Figure 5 、 Figure 7 The results also show that the target products prepared in Example 2 and Example 4 have the same Figure 1 Similar results.
[0059] Figure 2 The transmission electron microscope (TEM) photograph of the target product obtained in Example 1 shows that the prepared Cr2Se3 is a nanomaterial with a sheet structure, with a thickness of about 2 to 5 nm and a length of about 20 to 100 nm. Figure 6 The results also show that the target product prepared in Example 3 has Figure 2 Similar results.
[0060] In addition, the Figure 2 and Figure 6 The results also show that the target product exhibits a multi-level structure characterized by the self-assembly of several two-dimensional Cr2Se3 porous nanomaterials. As shown in the figure, the multi-level structure refers to a structure similar to a "nanoflower" formed by the cross-self-assembly of multiple nanosheets. Compared with a single nanosheet, the multi-level nanostructure has the following advantages: (1) It can reflect or scatter the incident light multiple times, thereby improving the light absorption efficiency. (2) It can solve the problem of easy stacking and agglomeration between nanosheets.
[0061] Figure 3 This is the ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectrum of the product obtained in Example 1, which proves that the two-dimensional Cr2Se3 nanosheet material has strong absorption ability in the visible-near-infrared light range, indicating that the two-dimensional Cr2Se3 nanosheet material can be used as a light-absorbing material in research fields such as photocatalysis and photoelectric conversion.
[0062] Figure 4This is the result of photocatalytic degradation of methylene blue by the product obtained in Example 1. First, the surface of the two-dimensional Cr2Se3 nanosheet material was modified by mercaptopropionic acid to enhance its water solubility, that is, the two-dimensional Cr2Se3 nanosheet material was dispersed in a mixture of cyclohexane and mercaptopropionic acid with a volume ratio of 3:1 under ultrasonic action, left to stand for 24 hours, and then washed by centrifugation with anhydrous ethanol 3 times. Secondly, 50 mg of the target product was weighed and dispersed into 50 mL of a methylene blue aqueous solution with a concentration of 10 mg / L, and stirred in the dark for 30 minutes to reach adsorption / desorption equilibrium. Then, a 300W xenon lamp was used for irradiation, and 1.0 mL of the mixed solution was removed every 10 minutes for centrifugation. The supernatant was taken and the absorbance at a wavelength of 664 nm was measured by ultraviolet-visible spectrophotometer to calculate the degradation rate. Figure 4 As shown, the two-dimensional Cr2Se3 nanosheets have good degradation ability for methylene blue dye.
[0063] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.
Claims
1. A method for preparing a two-dimensional Cr2Se3 nanomaterial, characterized in that: The two-dimensional Cr2Se3 nanomaterial is a hexagonal crystal, and the main diffraction peaks in its XRD diffraction pattern are located at 30.8±0.1°, 32.6±0.1°, 42.6±0.1°, 50.7±0.1°, 56.1±0.1°, 61.7±0.1°, and 64.3±0.1°, respectively; the microscopic morphology is a nanoscale flake with a thickness of 2-5 nm and a side length of 20-100 nm; The preparation method comprises the following steps: adding a soluble chromium source and a selenium source into a high-boiling-point reaction medium to carry out a solvent thermal reaction, and separating a solid reaction product to obtain the product; The high-boiling-point reaction medium is a mixture of organic amine and oleic acid in a volume ratio of 1 to 7:
1. The solvent thermal reaction includes a first stage and a second stage: in the first stage, the chromium source and the selenium source are added to the reaction medium under an inert gas atmosphere, and the reaction medium is heated to 130 to 180° C. and reacted for 30 to 90 minutes; in the second stage, the reaction system is further heated to maintain the temperature between 260 to 350° C., and the reaction time is controlled between 5 and 180 minutes.
2. The preparation method according to claim 1, wherein In the solvent thermal reaction system, the molar ratio of Cr:Se elements is 1:1.5-3.
3. The preparation method according to claim 1, wherein The chromium source is one or a combination of chromium acetylacetonate, chromium trichloride, chromium nitrate or chromium acetate; the selenium source is one or a combination of diphenyl diselenide, dibenzyl diselenide, selenium dioxide or selenium powder.
4. The preparation method according to claim 1, wherein The organic amine is selected from one or a combination of oleylamine, octadecylamine and hexadecylamine.
5. Use of the two-dimensional Cr2Se3 nanomaterial prepared by the method according to any one of claims 1 to 4 as a photocatalytic degradation material, characterized in that: The application is for degradation of dye pollutants in water environment; the dye is methyl blue, methylene blue or Sudan red.
6. A method for degrading methylene blue in an aquatic environment, characterized in that: The method comprises dispersing the two-dimensional Cr2Se3 nanomaterial prepared by the method according to any one of claims 1 to 4 into a water environment that needs to be treated.
7. The method for degrading methylene blue in an aqueous environment as claimed in claim 6, wherein: The steps of the degradation method are as follows: using mercaptopropionic acid to modify the surface of the two-dimensional Cr2Se3 nanomaterial; dispersing the modified nanomaterial into a water environment to be treated to dissolve it, and then irradiating it with light.