A yolk-shell CuO@MnO2 nanocomposite microsphere with multi-point dispersion type core and a preparation method thereof

Abstract

The application discloses yolk-shell type CuO@MnO2 nano composite microspheres with a multi-point dispersion type inner core and a preparation method thereof. Organic carboxylic acid and copper salt are reacted in water, and after the reaction is completed, the organic copper carboxylate aqueous solution is filtered; after the solvent is removed, the organic copper carboxylate powder solid is obtained; the organic copper carboxylate powder solid is dissolved in a water and ethanol mixed solution; the silicon source ethanol solution is added for reaction; after the reaction is completed, the template agent is separated; the template agent is dispersed in a potassium permanganate solution; the reaction is heated under ultrasonic assistance; after the reaction is completed, the solid is placed in lye and heated to reflux; after centrifugal drying, the yolk-shell type CuO@MnO2 nanometer material with the multi-point dispersion type inner core is obtained by calcination. The yolk-shell type CuO@MnO2 nanometer material with the multi-point dispersion type inner core prepared by the application has the multi-point dispersion type CuO inner core in the MnO2 cavity, and has good application effect when applied to catalytic oxidative degradation of p-nitrophenol.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanomaterials, and particularly relates to a yolk-shell CuO@MnO2 nanocomposite microsphere with a multi-point dispersed core and a preparation method thereof. BACKGROUND

[0002] Yolk-shell nanostructure composite material is a new type of nanomaterial discovered in recent years, which has the characteristics of low density, high specific surface area and easy modification, and the cavity part can enrich more reactant molecules to participate in the reaction, and the shell can act as a protective layer to prevent the aggregation of the core, and has a very broad application prospect in the fields of catalysis, separation and energy storage. Generally speaking, the Yolk-shell structure material is obtained by sacrificing the template method or through the Oswald ripening effect, and it is difficult to obtain a multi-point dispersed core, which affects its activity. The multi-point dispersed core has a larger specific surface area and a higher proportion of surface atoms, and has a higher activity under the action of cavity confinement. SUMMARY

[0003] In view of the problem that the Yolk-shell structure material in the prior art is difficult to obtain a multi-point dispersed core, the application provides a yolk-shell CuO@MnO2 nanocomposite microsphere with a multi-point dispersed core and a preparation method thereof, which obtains a multi-point dispersed CuO core in the MnO2 cavity and applies it to catalytic oxidation degradation of p-nitrophenol, and has good application effect.

[0004] The application is achieved by the following technical scheme:

[0005] A preparation method of a yolk-shell CuO@MnO2 nanocomposite microsphere with a multi-point dispersed core, comprising the following steps:

[0006] (1) Preparation of copper carboxylate: reacting organic carboxylic acid and copper salt in water, filtering to obtain a copper carboxylate aqueous solution after the reaction is completed, and removing the solvent to obtain a copper carboxylate powder solid;

[0007] (2) Preparation of a template agent: dissolving the copper carboxylate powder solid prepared in step (1) in a mixed solution of water and ethanol, adding an ethanol solution of a silicon source to react, and separating to obtain a template agent after the reaction is completed;

[0008] (3) Preparation of a yolk-shell CuO@MnO2 nanomaterial: dispersing the template agent in step (2) in a potassium permanganate solution, heating and reacting under ultrasonic assistance, placing the solid after the reaction is completed in a lye and heating to reflux, and then centrifuging, drying and calcining to obtain a yolk-shell CuO@MnO2 nanomaterial with a multi-point dispersed core.

[0009] Further, the organic carboxylic acid in step (1) is halogenated acid or amino acid, and the copper salt is divalent copper salt; the silicon source in step (3) is amino silane or ethyl silicate, and the alkali solution is 1-10 mol / L soluble alkali solution.

[0010] Further, the organic carboxylic acid in step (1) is bromoacetic acid or arginine, and the copper salt is basic copper carbonate; the silicon source in step (3) is 3-aminopropyl triethoxysilane, and the alkali solution is 1.5 mol / L sodium carbonate or sodium hydroxide solution.

[0011] Further, the concentration of the organic carboxylic acid in water in step (1) is 0.1-2 mol / L, and the molar ratio of the organic carboxylic acid to the copper salt is 2:1-10:1; the volume ratio of water to ethanol in the water and ethanol mixed solution in step (2) is 1:15-1:150; and the concentration of the KMnO4 solution in step (3) is 0.1-1 mol / L.

[0012] Further, the molar ratio of the organic carboxylic acid to the copper salt in step (1) is 2:1; the volume ratio of water to ethanol in the water and ethanol mixed solution in step (2) is 1:70, and the molar ratio of the silicon source to the organic carboxylic acid copper is 2:1; and the concentration of the KMnO4 solution in step (3) is 0.1 mol / L.

[0013] Further, the reaction temperature in step (1) is 20-90 ℃, and the reaction time is 2-72 h; the reaction temperature in step (2) is 25-60 ℃, and the reaction time is 2-24 h; the temperature for soaking in the alkali solution in step (2) is 20-90 ℃, and the soaking time is 12-48 h; and the reaction temperature for ultrasonic-assisted heating reaction in step (3) is 25-40 ℃, and the reaction time is 0.5-3 h.

[0014] Further, the concentration of the dissolved organic carboxylic acid copper solid in step (2) is 0.03-0.08 mmol / mL, and the concentration of the silicon source ethanol solution is 0.06-0.16 mmol / mL; and the calcination temperature in step (3) is 400-700 ℃, the heating rate is 1-10 ℃ / min, and the holding time is 10-120 min.

[0015] Further, the calcination temperature in step (3) is 600 ℃, the heating rate is 5 ℃ / min, and the holding time is 60 min.

[0016] In the present application, the yolk-shell type CuO@MnO2 nanocomposite microspheres with multi-point dispersed inner core are prepared by the preparation method.

[0017] The yolk-shell type CuO@MnO2 nanocomposite microspheres with multi-point site dispersed core are used as catalysts in catalytic degradation of p-nitrophenol.

[0018] The application has the following beneficial effects:

[0019] (1) The application uses SiO2 material loaded with high dispersion CuO as a template agent, and obtains yolk-shell type CuO@MnO2 nanomaterials with a multi-point site dispersed core through a sacrifice template method and high-temperature calcination, and the CuO core is dispersed in the MnO2 cavity, which is applied to catalytic oxidation degradation of p-nitrophenol, and has good application effect.

[0020] (2) The application has mild reaction conditions, simple reaction steps, no need for complex equipment and harsh conditions, and non-toxic reaction reagents, and the method is simple and efficient, and is an environment-friendly synthesis method. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The SEM picture of the yolk-shell type CuO@MnO2 nanomaterials prepared in Example 1 of the application.

[0022] Figure 2 The TEM picture of the yolk-shell type CuO@MnO2 nanomaterials prepared in Example 1 of the application.

[0023] Figure 3 The XRD picture of the yolk-shell type CuO@MnO2 nanomaterials prepared in Example 1 of the application.

[0024] Figure 4 The degradation curve of the yolk-shell type CuO@MnO2 nanomaterials prepared in Example 1 of the application as catalysts in catalytic oxidation degradation of p-nitrophenol. DETAILED DESCRIPTION

[0025] The above content of the application is further described in detail through the following examples and drawings, but this should not be understood as the scope of the above subject matter of the application being limited to the following examples and drawings, and all technologies realized based on the above content of the application belong to the scope of the application.

[0026] Example 1

[0027] (1) Preparation of copper bromoacetate: 0.2 mol of bromoacetic acid was added to a single-neck round-bottom flask containing 100 mL of high-purity water, and then 0.1 mol of basic copper carbonate powder was slowly added, and the two were reacted at 60℃ water bath for 24 h, and a blue clear solution was obtained by filtration, and the blue clear solution was rotary evaporated at 60℃ to obtain a dark blue solid powder (CuBA).

[0028] (2) Preparation of CuBA@SiO2 template: 2.5 mmol CuBA was dissolved in 1 mL high-purity water and 35 mL anhydrous ethanol to obtain a CuBA solution, and 5 mmol 3-aminopropyl triethoxysilane (APTES) was dissolved in 35 mL anhydrous ethanol, which was slowly added to the above CuBA solution, and after the addition was completed, it was reacted in a 60 ℃ water bath for 4 h, then it was left standing for 12 h, then it was centrifuged, washed twice with anhydrous ethanol, and the centrifuged sample was placed in a 40 ℃ vacuum drying oven to obtain the CuBA@SiO2 template;

[0029] (3) Preparation of yolk-shell type CuO@MnO2 nanomaterial: 0.5 g CuBA@SiO2 template was dispersed in 300 mL 0.1 mol / L KMnO4 solution, and ultrasonic assisted 25 ℃ water bath reaction was carried out for 0.5 h, then it was centrifuged, washed with high-purity water for 4 times, and then dispersed in 100 mL 1.5 mol / L NaCO3 solution, and refluxed and heated for 60 min, the heating temperature was 90 ℃, then it was centrifuged and dried, and the temperature was increased to 600 ℃ at a rate of 5 ℃ / min, and calcined in air atmosphere at 600 ℃ for 30 min to obtain the yolk-shell type CuO@MnO2 nanomaterial.

[0030] The SEM picture of the yolk-shell type CuO@MnO2 nanomaterial prepared in Example 1 is shown in Figure 1 , from which it can be seen that the micro-morphology of the obtained material is regular spherical, and the particle size is about 500 nm; the TEM picture of the yolk-shell type CuO@MnO2 nanomaterial prepared in Example 1 is shown in Figure 2 , from which it can be seen that the internal hollow structure and the multiple-point CuO core existing in the cavity can be seen; the XRD chart of the yolk-shell type CuO@MnO2 nanomaterial prepared in Example 1 is shown in Figure 3 , in which two sets of obvious characteristic diffraction peaks appear, which are the characteristic diffraction peaks of CuO and MnO2 respectively by comparison with standard substance card.

[0031] Example 2

[0032] (1) Preparation of copper arginine: 0.2 mol arginine was added to a single-neck round-bottom flask containing 100 mL high-purity water, and then 0.1 mol basic copper carbonate powder was slowly added, and the two were reacted at 60 ℃ water bath for 24 h, and then filtered to obtain a blue clear solution, which was rotary evaporated at 60 ℃ to obtain a dark blue solid powder (CuArg);

[0033] (2) Preparation of CuArg@SiO2 template: 2.5 mmol CuArg was dissolved in 1 mL high-purity water and 35 mL anhydrous ethanol, 5 mmol ethyl silicate was dissolved in 35 mL anhydrous ethanol, and then the solution was slowly added to the CuArg solution. After the addition was completed, the solution was reacted in a 60 ℃ water bath for 4 h, and then was left to stand for 12 h. Then, the solution was centrifuged, washed with anhydrous ethanol for 3 times, and centrifuged. The sample after centrifugation was placed in a 40 ℃ vacuum drying oven for drying to obtain the CuArg@SiO2 template;

[0034] (3) Preparation of yolk-shell CuO@MnO2 nanomaterial: 0.5 g CuArg@SiO2 template was dispersed in 300 mL 0.1 mol / L KMnO4 solution, and then was reacted in a 25 ℃ water bath under ultrasonic assistance for 0.5 h. After centrifugation, the solution was washed with high-purity water for 4 times, and then was dispersed in 100 mL 1.5 mol / L NaOH solution for reflux heating at 90 ℃ for 60 min. After centrifugation and drying, the solution was heated to 600 ℃ at a rate of 5 ℃ / min, and then was calcined in an air atmosphere at 600 ℃ for 30 min to obtain the yolk-shell CuO@MnO2 nanomaterial.

[0035] Application Example

[0036] Catalytic reaction system: 100 mL (0.01 mg / mL) p-nitrophenol, hydrogen peroxide concentration was 1000 ppm, yolk-shell CuO@MnO2 nanomaterial prepared in Example 1 was added as a catalyst, and the catalyst concentration was 0.05 mg / mL-0.2 mg / mL. The degradation curve of p-nitrophenol in the catalytic oxidation degradation is shown in Figure 4 , and it can be seen from Figure 4 that the catalytic degradation rate is accelerated with the increase of the catalyst concentration. The yolk-shell CuO@MnO2 nanomaterial prepared in the application has good effect on catalytic degradation of p-nitrophenol.

[0037] The above only describes the preferred embodiments of the application and is not used to limit the application. Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core, characterized in that, Includes the following steps: (1) Preparation of organic carboxylic acid copper: Organic carboxylic acid and copper salt are reacted in water. The organic carboxylic acid is bromoacetic acid or arginine. After the reaction is completed, the organic carboxylic acid copper aqueous solution is obtained by filtration. After removing the solvent, organic carboxylic acid copper powder solid is obtained. (2) Preparation of CuBA@SiO2 or CuArg@SiO2 template agent: Dissolve the solid organic carboxylic acid copper powder prepared in step (1) in a mixed solution of water and ethanol. The copper salt is a divalent metal copper salt. Add an ethanol solution of silicon source to react. After the reaction is completed, separate the CuBA@SiO2 or CuArg@SiO2 template agent. (3) Preparation of yolk-shell CuO@MnO2 nanomaterials: The CuBA@SiO2 or CuArg@SiO2 template agent in step (2) is dispersed in potassium permanganate solution and heated under ultrasonic assistance. After the reaction is completed, the solid is placed in alkaline solution and heated under reflux, then centrifuged and dried, and calcined to obtain yolk-shell CuO@MnO2 nanomaterials with multi-site dispersed cores.

2. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 1, characterized in that, The silicon source mentioned in step (2) is an aminosilane or ethyl silicate, and the alkaline solution is a 1~10 mol / L soluble alkaline solution.

3. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 2, characterized in that, The copper salt mentioned in step (1) is basic copper carbonate; the alkaline solution is a 1.5 mol / L sodium carbonate or sodium hydroxide solution.

4. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 1, characterized in that, In step (1), the concentration of organic carboxylic acid in water is 0.1~2 mol / L, and the molar ratio of organic carboxylic acid to copper salt is 2:1~10:1; in step (2), the volume ratio of water to ethanol in the mixed solution of water and ethanol is 1:15~1:150; in step (3), the concentration of KMnO4 solution is 0.1~1 mol / L.

5. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 1, characterized in that, In step (1), the molar ratio of organic carboxylic acid to copper salt is 2:1; in step (2), the volume ratio of water to ethanol in the mixed solution of water and ethanol is 1:70, and the molar ratio of silicon source to copper in organic carboxylic acid is 2:1; in step (3), the concentration of KMnO4 solution is 0.1 mol / L.

6. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 1, characterized in that, In step (1), the reaction temperature is 20~90℃ and the reaction time is 2~72h; in step (2), the reaction temperature is 25~60℃ and the reaction time is 2~24h; in step (2), the soaking temperature in the alkaline solution is 20~90℃ and the soaking time is 12~48h; in step (3), the reaction temperature of the ultrasonic-assisted heating reaction is 25~40℃ and the reaction time is 0.5~3h.

7. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 1, characterized in that, In step (2), the concentration of the dissolved organic carboxylic acid copper solid is 0.03~0.08 mmol / mL, and the concentration of the silicon source ethanol solution is 0.06~0.16 mmol / mL; in step (3), the calcination temperature is 400~700℃, the heating rate is 1~10℃ / min, and the holding time is 10~120min.

8. The method for preparing yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core according to claim 7, characterized in that, In step (3), the calcination temperature is 600℃, the heating rate is 5℃ / min, and the holding time is 60min.

9. A yolk-shell type CuO@MnO2 nanocomposite microsphere with a multi-site dispersed core prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the yolk-shell CuO@MnO2 nanocomposite microspheres with a multi-site dispersed core as described in claim 9 as a catalyst in the catalytic degradation of p-nitrophenol.

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