Copper oxide nanosheet, and preparation method and application thereof

Abstract

The application discloses copper oxide nanosheets, a preparation method and application thereof. The preparation method comprises the following steps: dispersing layered copper hydroxide acetate in an intercalation agent solution to perform ion exchange; adjusting the solution obtained after the ion exchange to be alkaline, and heating to reflux to obtain black precipitate; and washing and drying the black precipitate to obtain the copper oxide nanosheets. The method has mild conditions, and the copper oxide nanosheets prepared by the method have large lateral size and thin thickness, and can be well used in optical limiting devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nonlinear optical materials. More particularly, it relates to a copper oxide nanosheet and a preparation method and application thereof. BACKGROUND

[0002] In recent years, the emerging two-dimensional nanomaterials have more novel photoelectric properties than bulk materials due to the unique two-dimensional quantum confinement effect. In the field of optical limiting, two-dimensional materials generally have the advantages of fast response speed, low limiting threshold, wide protection band and high transmittance, showing good application prospects. The preparation methods of two-dimensional materials are divided into top-down method and bottom-up method. For layered bulk crystals connected by strong chemical bonds within the plane and weak van der Waals forces between the planes, the preparation method of two-dimensional materials is mostly to peel off from the bulk material from top to bottom. For more common non-layered materials, which are connected by chemical bonds in three dimensions, such as noble metals, metal oxides and metal chalcogenides, in order to obtain their two-dimensional structure, only the bottom-up method can be used, and special methods are needed to control the growth direction during the synthesis process. Nanomaterials are usually dispersed in solvents, but due to the long-term instability of the solvent itself and the material in the solvent, they are not suitable for practical applications, so it is of practical application value to provide a suitable matrix for nanomaterials and prepare them into devices. Nonlinear optical devices usually need to have good transparency and stability. Among various matrices, glass is widely used due to its high linear transmittance, chemical and mechanical stability, such as sol-gel glass, borate glass, oxide glass, etc.

[0003] Copper oxide is a non-layered transition metal oxide, which has the advantages of rich natural reserves, non-toxicity, high thermal stability and chemical stability. The band gap of copper oxide is between 1.2-1.4 eV. Due to its unique properties of light, heat, electricity, superconductivity and the like, copper oxide has been widely used in the fields of catalysis, electrode, solar energy conversion, sensor and the like. In general synthesis process, the morphology of copper oxide material is mostly nanospheres or nanoparticles. Therefore, in order to obtain two-dimensional nanosheets with more excellent performance, special methods are needed to control the growth direction. At present, the preparation methods of copper oxide nanosheets include hydrothermal method, calcination method, sol-gel method and the like. However, most of the methods need high temperature and high pressure conditions, which limits the further production and application. In some prior art, the calcination method is used to prepare sheet-shaped nanometer, but the calcination method needs high temperature of 300-600℃; in some reports, copper oxide nanosheets are synthesized by hydrothermal method, the width of the synthesized nanosheets is about 500 nm, and the length is about 1 μm, but special equipment autoclave is needed in the synthesis process. Therefore, it is of great significance to invent a preparation method with simple process and mild reaction conditions. Therefore, the improved and safer thermal conversion intercalation method of layered copper hydroxide can be used to prepare copper oxide nanosheets with larger lateral size. SUMMARY

[0004] In order to prepare copper oxide nanosheets with large lateral size and thin thickness under mild and environmentally friendly conditions, the present application provides a kind of copper oxide nanosheet and its preparation method and application.

[0005] In one aspect, the present application provides a preparation method of copper oxide nanosheet, comprising the following steps:

[0006] The layered basic copper acetate is dispersed in the intercalation agent solution for ion exchange;

[0007] The solution obtained after ion exchange is adjusted to alkaline, heated and refluxed to obtain black precipitate;

[0008] The black precipitate is washed and dried to obtain the copper oxide nanosheet.

[0009] Further, the layered basic copper acetate is prepared by a method comprising the following steps:

[0010] The aqueous solution of soluble base is slowly added to the mixture of copper acetate aqueous solution and ethanol for reaction, and the blue precipitate obtained after stirring and centrifugation is the layered basic copper acetate.

[0011] Further, the concentration of the aqueous solution of soluble base is 0.01-1 mol / L, and the dropping rate is 1-3 drops per second.

[0012] Further, the soluble base is selected from sodium hydroxide or potassium hydroxide.

[0013] Further, the concentration of the copper acetate aqueous solution is 0.01-1 mol / L.

[0014] Further, the molar ratio of copper acetate in the copper acetate aqueous solution to the base in the soluble base aqueous solution is greater than 1:1.

[0015] Further, the volume ratio of the ethanol to the copper acetate aqueous solution is greater than 1:2.

[0016] Further, the intercalation agent solution is an aqueous solution of the intercalation agent, and the concentration is 0.01-0.05 g / mL, preferably 0.03 g / mL.

[0017] Further, the intercalation agent is selected from one or more of cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate or sodium dodecyl sulfate.

[0018] Further, the molar ratio of the intercalation agent in the intercalation agent solution to the layered basic copper acetate is greater than 1:1.

[0019] Further, the ion exchange time is greater than 24 hours.

[0020] Further, the heating reflux temperature is greater than 50℃, and the time is greater than 1 hour.

[0021] Further, the method for adjusting the solution obtained after ion exchange to be alkaline is adding an alkaline reagent to the solution. Preferably, the alkaline reagent includes but is not limited to one or more selected from sodium hydroxide, potassium hydroxide and sodium carbonate.

[0022] In another aspect, the present application provides the copper oxide nanosheet prepared by the preparation method as described above.

[0023] Further, the lateral size of the copper oxide nanosheet is 400-600 nm, preferably 400-550 nm, and more preferably 500 nm, and the thickness is less than 15 nm.

[0024] In another aspect, the present application provides a light-amplitude-limiting solid device, which comprises a gel glass matrix and the copper oxide nanosheet as described above doped in the gel glass matrix.

[0025] Further, the doping mass concentration of the copper oxide nanosheet in the gel glass matrix is 0.01-2 wt%.

[0026] The beneficial effects of the present application are as follows:

[0027] In the preparation method of the copper oxide nanosheet provided in the present application, the copper oxide nanosheet can be formed in situ by adding sodium hydroxide solution and heating after ion exchange, without high-temperature calcination or high-pressure reaction. The preparation method is simple, has mild reaction conditions, is easy to operate, and is performed in an open container. In addition, the preparation method can be used to prepare copper oxide nanosheets with uniform morphology, large lateral size, and small thickness. The copper oxide nanosheets prepared in the present application have uniform morphology, large lateral size, and small thickness, and when doped into a glass substrate, the glass device has a smooth surface and the copper oxide nanosheets are uniformly dispersed, and can be used as an optical limiting glass device. The optical limiting glass device has a low limiting threshold at 532 nm and 1064 nm. BRIEF DESCRIPTION OF DRAWINGS

[0028] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0029] Figure 1 A scanning electron microscope image of the copper oxide nanosheet in Example 1 is shown.

[0030] Figure 2 A transmission electron microscope image of the copper oxide nanosheet in Example 1 is shown.

[0031] Figure 3 An XRD spectrum of the copper oxide nanosheet in Example 1 is shown.

[0032] Figure 4 A gel glass photo of the copper oxide nanosheet in Example 1 is shown.

[0033] Figure 5 A linear transmittance of the copper oxide nanosheet gel glass in Example 1 is shown.

[0034] Figure 6 An optical limiting curve of the copper oxide nanosheet gel glass in Example 1 is shown.

[0035] Figure 7 A transmission electron microscope image of the copper oxide product in Comparative Example 1 is shown.

[0036] Figure 8 A transmission electron microscope image of the copper oxide product in Comparative Example 2 is shown. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the present application, the present application will be further described below with reference to the preferred embodiments and the accompanying drawings. Like components are denoted by the same reference numerals in the drawings. Those skilled in the art should understand that the specific descriptions below are illustrative rather than limiting, and should not limit the scope of protection of the present application.

[0038] Example 1

[0039] A preparation method of copper oxide nanosheets and a light limiting solid device, comprising the following steps:

[0040] Step S1: copper acetate is dissolved in deionized water to prepare a 0.1 mol / L copper acetate solution, 10 mL of ethanol is added, and sodium hydroxide is dissolved in deionized water to prepare a 0.1 mol / L sodium hydroxide solution;

[0041] Step S2: 48 mL of the sodium hydroxide solution is added to 40 mL of the copper acetate solution at a speed of 2 drops per second, and the volume ratio is 1.2:1, a blue layered basic copper acetate precipitate is formed, and after stirring for 10 minutes, a blue precipitate is obtained by centrifugation;

[0042] Step S3: 6 g of CTAB is dissolved in 180 mL of deionized water and 20 mL of ethanol to prepare a CTAB solution;

[0043] Step S4: the copper acetate blue precipitate is dispersed in the CTAB solution for ion exchange, and is kept under magnetic stirring for 48 hours;

[0044] Step S5: 3 mL of a 0.3 g / mL sodium hydroxide solution is added to the ion-exchanged solution, and is heated to reflux at 90°C for 4 hours to obtain a black precipitate, which is washed with ethanol and water for multiple times and dried to obtain copper oxide nanosheets;

[0045] Step S6: the copper oxide nanosheets obtained in Example 1 are dissolved in ethanol, and are doped into a methyltriethoxysilane matrix by a sol-gel method, and the doping mass concentrations are 0%, 0.01%, 0.03%, 0.05% and 0.07%, respectively.

[0046] Figure 1 and Figure 2 are a scanning electron microscope image and a transmission electron microscope image of the copper oxide nanosheets prepared in Example 1, and it can be seen that the morphology of the copper oxide nanosheets is uniform, the lateral size is about 500 nm, and the thickness is about 13 nm.

[0047] Figure 3 is an XRD spectrum of the copper oxide nanosheets prepared in Example 1, and it shows that the prepared material is copper oxide and has good crystallinity.

[0048] Figure 4 is a gel glass photo of the copper oxide nanosheets with different doping mass concentrations prepared in Example 1, and it can be seen that the surface of the glass is smooth without cracks, and the copper oxide nanosheets are uniformly dispersed in the matrix.

[0049] Figure 5The linear transmittance of the gel glass of copper oxide nanosheets with different doping mass concentrations prepared in Example 1 in the ultraviolet-visible light near-infrared band, wherein the glass with a doping mass concentration of 0.01% has a higher transmittance in the 200-1500 nm band, greater than 60%; the glass with a doping mass concentration of 0.03% has a transmittance in the 200-1500 nm band between 40%-50%.

[0050] Figure 6 The optical limiting curves of the glass with a doping mass concentration of 0.03% prepared in Example 1 at 532 nm and 1064 nm, the glass has excellent optical limiting performance, and the limiting threshold values are 0.17 and 0.27 J / cm 2 .

[0051] Example 2

[0052] A preparation method of copper oxide nanosheets and an optical limiting solid device, comprising the following steps:

[0053] Step S1: Dissolve copper acetate in deionized water to prepare a 0.1 mol / L copper acetate solution, add 10 mL of ethanol, and dissolve sodium hydroxide in deionized water to prepare a 0.1 mol / L sodium hydroxide solution;

[0054] Step S2: Add 48 mL of sodium hydroxide solution to 40 mL of copper acetate solution at a rate of 2 drops per second, with a volume ratio of 1.2:1, to form a blue layered basic copper acetate precipitate, and after stirring for 10 minutes, centrifuge to obtain a blue precipitate;

[0055] Step S3: Dissolve 6 g of CTAB in 180 mL of deionized water and 20 mL of ethanol to prepare a CTAB solution;

[0056] Step S4: Disperse the copper acetate blue precipitate in the CTAB solution for ion exchange, and keep under magnetic stirring for 48 hours.

[0057] Step S5: Add 3 mL of 0.3 g / mL sodium hydroxide solution to the ion-exchanged solution, heat under reflux at 100°C for 4 hours to obtain a black precipitate, and wash with ethanol and water several times and dry to obtain copper oxide nanosheets.

[0058] Step S6: Dissolve the copper oxide nanosheets obtained in Example 2 in ethanol and dope into a methyltriethoxysilane matrix by a sol-gel method.

[0059] Copper oxide nanosheets with uniform morphology were obtained, with lateral size of 500 nm and thickness of 11 nm, similar to Example 1. The obtained copper oxide nanosheet gel glass has smooth surface and uniform dispersion of copper oxide nanosheets, and has low limiting amplitude threshold, similar to Example 1. The limiting amplitude threshold of the glass doped with 0.03% mass concentration at 532 nm and 1064 nm is 0.15 and 0.27 J / cm 2 .

[0060] Example 3

[0061] A preparation method of copper oxide nanosheets and a light limiting solid device, comprising the following steps:

[0062] Step S1: copper acetate is dissolved in deionized water to prepare a 0.1 mol / L copper acetate solution, 10 mL of ethanol is added, and sodium hydroxide is dissolved in deionized water to prepare a 0.1 mol / L sodium hydroxide solution;

[0063] Step S2: 48 mL of sodium hydroxide solution is added to 40 mL of copper acetate solution at a rate of 2 drops per second, with a volume ratio of 1.2:1, to form a blue layered basic copper acetate precipitate. After stirring for 10 minutes, the blue precipitate is obtained by centrifugation;

[0064] Step S3: 6 g of CTAB is dissolved in 180 mL of deionized water and 20 mL of ethanol to prepare a CTAB solution;

[0065] Step S4: The copper acetate blue precipitate is dispersed in the CTAB solution for ion exchange, and is kept under magnetic stirring for 48 hours.

[0066] Step S5: 3 mL of 0.3 g / mL sodium hydroxide solution is added to the ion-exchanged solution, and is heated to reflux at 110°C for 4 hours to obtain a black precipitate. After washing with ethanol and water for several times, the copper oxide nanosheets are obtained by drying.

[0067] Step S6: The copper oxide nanosheets obtained in Example 3 are dissolved in ethanol and doped into a methyltriethoxysilane matrix by a sol-gel method.

[0068] Copper oxide nanosheets with uniform morphology were obtained, with lateral size of 500 nm and thickness of 13 nm, similar to Example 1. The obtained copper oxide nanosheet gel glass has smooth surface and uniform dispersion of copper oxide nanosheets, and has low limiting amplitude threshold, similar to Example 1. The limiting amplitude threshold of the glass doped with 0.03% mass concentration at 532 nm and 1064 nm is 0.17 and 0.27 J / cm 2 .

[0069] Example 4

[0070] A preparation method of copper oxide nanosheets and a light limiting solid device, comprising the following steps:

[0071] Step S1: copper acetate is dissolved in deionized water to prepare a 0.1 mol / L copper acetate solution, 10 mL of ethanol is added, and sodium hydroxide is dissolved in deionized water to prepare a 0.1 mol / L sodium hydroxide solution;

[0072] Step S2: 48 mL of the sodium hydroxide solution is added to the 40 mL copper acetate solution at a rate of 2 drops per second, with a volume ratio of 1.2:1, to form a blue layered basic copper acetate precipitate, and after stirring for 10 minutes, a blue precipitate is obtained by centrifugation;

[0073] Step S3: 4.6 g of sodium dodecyl sulfate is dissolved in 180 mL of deionized water and 20 mL of ethanol to prepare a solution;

[0074] Step S4: the copper acetate blue precipitate is dispersed in the sodium dodecyl sulfate solution for ion exchange, and is kept under magnetic stirring for 48 hours.

[0075] Step S5: 3 mL of a 0.3 g / mL sodium hydroxide solution is added to the ion-exchanged solution, and is heated to reflux at 90°C for 4 hours to obtain a black precipitate, which is washed with ethanol and water multiple times and dried to obtain copper oxide nanosheets.

[0076] Step S6: the copper oxide nanosheets obtained in Example 4 are dissolved in ethanol and doped into a methyltriethoxysilane matrix by a sol-gel method.

[0077] Uniform copper oxide nanosheets with a lateral size of 500 nm and a thickness of 12 nm are obtained. The obtained copper oxide nanosheet gel glass has a smooth surface, the copper oxide nanosheets are uniformly dispersed, the glass has a low limiting threshold, which is similar to that of Example 1, and the limiting threshold of the glass doped with a mass concentration of 0.03% at 532 nm and 1064 nm is 0.16 and 0.28 J / cm 2 .

[0078] Example 5

[0079] A preparation method of copper oxide nanosheets and a light limiting solid device, comprising the following steps:

[0080] Step S1: copper acetate is dissolved in deionized water to prepare a 0.1 mol / L copper acetate solution, 10 mL of ethanol is added, and sodium hydroxide is dissolved in deionized water to prepare a 0.1 mol / L sodium hydroxide solution;

[0081] Step S2: 48 mL of sodium hydroxide solution was added dropwise into 40 mL of copper acetate solution at a rate of 2 drops per second, the volume ratio was 1.2:1, a blue layered copper acetate basic precipitate was formed, after stirring for 10 minutes, the blue precipitate was centrifuged to obtain a blue precipitate;

[0082] Step S3: 5.6 g of sodium dodecyl benzene sulfonate was dissolved in 180 mL of deionized water and 20 mL of ethanol to prepare a solution;

[0083] Step S4: the copper acetate blue precipitate was dispersed in the sodium dodecyl benzene sulfonate solution for ion exchange, which was kept under magnetic stirring for 48 hours.

[0084] Step S5: 3 mL of sodium hydroxide solution with a concentration of 0.3 g / mL was added to the ion-exchanged solution, which was heated to reflux at 90°C for 4 hours to obtain a black precipitate, which was washed with ethanol and water for several times and dried to obtain copper oxide nanosheets.

[0085] Step S6: the copper oxide nanosheets obtained in Example 5 were dissolved in ethanol and doped into a methyl triethoxysilane matrix by a sol-gel method.

[0086] Uniform copper oxide nanosheets with a lateral size of 500 nm and a thickness of 13 nm were obtained, which were similar to those in Example 1. The obtained copper oxide nanosheet gel glass had a smooth surface, the copper oxide nanosheets were uniformly dispersed, the glass had a low damage threshold, which was similar to that in Example 1, and the damage threshold of the glass doped with a mass concentration of 0.03% at 532 nm and 1064 nm was 0.17 and 0.27 J / cm 2 .

[0087] The difference between Examples 1 to 3 was only the reflux temperature in Step S5, and the reflux temperatures of Examples 1 to 3 were 90°C, 100°C and 110°C respectively, and the obtained products were all copper oxide nanosheets with similar morphology and size. The difference between Example 1 and Examples 4 and 5 was only the intercalating agent in Step S3, and the intercalating agents of Example 1 and Examples 4 and 5 were cetyltrimethylammonium bromide, sodium dodecyl benzene sulfonate and sodium dodecyl sulfate respectively, and the obtained products were all copper oxide nanosheets with no difference in size and thickness.

[0088] Comparative Example 1

[0089] Example 1 was repeated, and the difference was only that the CTAB ion exchange in Step S4 was not performed in Comparative Example 1, and the other conditions were unchanged.

[0090] Figure 7 The transmission electron microscope image of the copper oxide nanosheets prepared for Comparative Example 1 showed that the obtained product was not in the form of sheets.

[0091] Comparative Example 2

[0092] Example 1 was repeated, the only difference was that the dropping speed of sodium hydroxide solution in step S2 of Comparative Example 2 was 5 mL per second, which was faster than that of Example 1. The other conditions were the same.

[0093] Figure 8 The TEM image of the copper oxide nanosheets prepared for Comparative Example 2 showed that the product was not in sheet form.

[0094] The product obtained in Comparative Example 2 was not in sheet form, which showed the importance of the dropping speed of sodium hydroxide solution to the morphology of the final product.

[0095] Comparative Example 3

[0096] Example 1 was repeated, the only difference was that ethanol was not added in step S1 of Comparative Example 2. The other conditions were the same.

[0097] Comparative Example 3 obtained a blue layered basic copper acetate precipitate in step S2, which contained a large amount of black precipitate. Copper oxide had begun to form during the centrifugation process, and the final product was not in sheet form.

[0098] Comparative Example 4

[0099] Example 2 was repeated, the only difference was that Comparative Example 4 did not perform the CTAB ion exchange in step S4. The other conditions were the same. The product was not in sheet form.

[0100] Comparative Example 5

[0101] Example 3 was repeated, the only difference was that Comparative Example 5 did not perform the CTAB ion exchange in step S4. The other conditions were the same. The product was not in sheet form.

[0102] Comparative Example 6

[0103] Example 3 was repeated, the only difference was that the amount of CTAB in step S4 of Comparative Example 1 was 1.5 g, and the molar ratio of CTAB to copper acetate was 1:1. The other conditions were the same. Part of the product was in sheet form, and part was in granular form.

[0104] Obviously, the above examples of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for preparing copper oxide nanosheets, characterized in that, The method comprises the following steps: dispersing the layered basic copper acetate in an intercalation agent solution to perform ion exchange; adjusting the solution obtained after ion exchange to be alkaline, and heating to reflux to obtain a black precipitate; washing and drying the black precipitate to obtain the copper oxide nanosheet.

2. The production method according to claim 1, characterized by, The layered basic copper acetate is prepared by a method comprising the following steps: slowly adding a water solution of soluble base to a mixture of copper acetate aqueous solution and ethanol, stirring, and centrifuging the blue precipitate obtained after reaction to obtain the layered basic copper acetate.

3. The production method according to claim 2, characterized by, The concentration of the water solution of soluble base is 0.01-1 mol / L, and the dropping rate is 1-3 drops per second.

4. The production method according to claim 3, characterized by, The concentration of the copper acetate aqueous solution is 0.01-1 mol / L, the molar ratio of copper acetate in the copper acetate aqueous solution to base in the water solution of soluble base is greater than 1:1, and the volume ratio of ethanol to copper acetate aqueous solution is greater than 1:

2.

5. The preparation method according to claim 1, characterized in that, The intercalation agent solution is a water solution of intercalation agent with a concentration of 0.01-0.05 g / mL. The intercalation agent is selected from one or more of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate or sodium dodecyl sulfate.

6. The method of claim 1, wherein, The intercalation agent solution is a water solution of intercalation agent with a concentration of 0.03 g / mL.

7. The preparation method according to claim 1, characterized in that, The molar ratio of the intercalation agent in the intercalation agent solution to the layered basic copper acetate is greater than 1:1; and / or The ion exchange time is greater than 24 hours.

8. The method of claim 1, wherein, The heating reflux temperature is greater than 50 ℃, and the time is greater than 1 hour.

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