阅读说明：本技术 石墨炔/中空铁酸锰纳米光催化剂的制备方法 (Preparation method of graphdiyne/hollow manganese ferrite nano photocatalyst ) 是由 张春 刘林 靳晓东 朱鸿睿 王康旺 于 2021-06-23 设计创作，主要内容包括：本发明公开了一种石墨炔/中空铁酸锰纳米光催化剂的制备方法,首先利用溶剂热法合成了碳包覆的中空铁酸锰纳米颗粒为前体,然后,将装有碳包覆的中空铁酸锰纳米颗粒的烧瓶做抽真空处理,使碳包覆的中空铁酸锰纳米颗粒的内部形成负压,浸泡到醋酸铜和吡啶的混合水溶液中,使醋酸铜和吡啶的混合水溶液中能够进入其中；磁选下倒出多余溶液仅保留纳米材料；再将六乙炔基苯的二氯甲烷溶液在氩气和黑暗条件下注入上述反应体系中,形成热力学稳定的体系；最后用磁铁提取产物,用无水乙醇洗涤,干燥,得到石墨炔/中空铁酸锰的纳米光催化剂复合材料。(The invention discloses a preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst, which comprises the steps of firstly synthesizing carbon-coated hollow manganese ferrite nano particles as a precursor by a solvothermal method, then vacuumizing a flask filled with the carbon-coated hollow manganese ferrite nano particles to enable the interior of the carbon-coated hollow manganese ferrite nano particles to form negative pressure, and soaking the carbon-coated hollow manganese ferrite nano particles into a mixed aqueous solution of copper acetate and pyridine to enable the mixed aqueous solution of the copper acetate and the pyridine to enter the flask; pouring out the redundant solution under magnetic separation to only retain the nano material; then, injecting a dichloromethane solution of hexaethynylbenzene into the reaction system under the conditions of argon and darkness to form a thermodynamically stable system; and finally, extracting a product by using a magnet, washing the product by using absolute ethyl alcohol, and drying to obtain the graphite alkyne/hollow manganese ferrite nano photocatalyst composite material.)

1. A preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst is characterized by comprising the following steps: the method comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing the product with deionized water/ethanol for many times, and drying the product at 60 ℃ for 8 hours in vacuum to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of the glucopyranose solution, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the polypopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, carrying out magnetic separation to obtain carbon-coated manganese ferrite nano particles, uniformly dispersing the particles into a mixed acid solution, soaking for 8 hours, washing, and drying to obtain carbon-coated hollow manganese ferrite nano particles;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a flask, vacuumizing the flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then, 0.005g-0.02g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and dark conditions, the reaction system is kept undisturbed for 24 hours, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon-coated hollow manganese ferrite nano composite material;

through detection, the saturation magnetization of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 29.7-35.6 emu/g.

2. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 1, characterized in that: and in the fifth step, the mixed acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3.

3. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 1 or 2, characterized in that: the dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

4. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 3, characterized in that: the high-pressure reaction kettle in the second step and the fifth step is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

5. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 4, characterized in that: the molar concentration of the glucopyranose solution in the third step is 0.15 mol/L.

6. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 5, characterized in that: and in the fourth step, the molar concentration of the gamma cyclodextrin solution is 0.04 mol/L.

7. The preparation method of the graphdine/hollow manganese ferrite nano photocatalyst according to claim 6, characterized in that: in the mixed aqueous solution of copper acetate and pyridine in the sixth step, the molar concentration of copper acetate is 0.01mol/L, and the molar concentration of pyridine is 0.25 mol/L.

Technical Field

The invention relates to the technical field of nano materials, in particular to a preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst.

Background

The graphyne (graphyne) is a novel material of a carbon family, has a two-dimensional structure similar to graphene, is formed by connecting double alkyne bonds formed by C-C, C ≡ C with benzene rings, and has high conjugation, a uniform pore structure and an adjustable electronic structure, and the excellent characteristics enable the graphyne to be widely concerned in the field of catalysis. Compared with a noble metal catalyst, the graphdiyne has the advantages of low price, rich raw materials and excellent electron transfer performance as shown by ultrahigh electron mobility, so the graphdiyne can be used for preparing a composite material. When the graphdine is used as a carbon-rich material to prepare the composite semiconductor photocatalyst, an electron transmission effect exists on the surface of the composite material, so that the graphdine and the semiconductor material generate a synergistic effect. The improvement of the catalytic performance is realized by adding the graphdiyne and reducing the recombination rate of the photoproduction electron hole pair. Based on excellent pi conjugate effect, ordered pore structure and larger specific surface area of the graphite alkyne material, the graphite alkyne composite material catalyst can be widely applied to the field of photocatalysis.

Manganese ferrite (manganese ferrite nanopowder) can generate photo-generated electron-hole pairs under the excitation of ultraviolet light and visible light. Along with the transition and transfer of electrons, the corresponding photocatalytic activity can also be well applied. In addition, the excellent magnetic property of the magnetic material also facilitates the recovery and the reuse of the magnetic material through an external magnetic field. Manganese ferrite has the advantages of low price, strong stability, high utilization rate and the like, but when the manganese ferrite is used as a photocatalyst, electron hole pairs generated under illumination can be rapidly recombined, and the photocatalytic activity is reduced. In order to enable the manganese ferrite to meet the actual requirements of the photocatalytic reaction, modification of materials such as design of a porous structure, construction of a heterostructure, inorganic doping and the like is often required.

Disclosure of Invention

The invention aims to provide a preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst, which is used for producing graphene coated carbon coated hollow manganese ferrite nano particles, has larger comparative area and good separation and recovery characteristics, and improves the photocatalytic performance.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing filter residue with deionized water/ethanol for many times, and vacuum drying the filter residue at 60 ℃ for 8 hours to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of a glucopyranose solution, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the glucopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, filtering to obtain polymer nanoparticles of the glucopyranose and the manganese ferrite, uniformly dispersing the polymer nanoparticles of the glucopyranose and the manganese ferrite into a mixed acid solution, soaking for 8 hours, washing and drying to obtain carbon-coated hollow manganese ferrite nanoparticles;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a flask, vacuumizing the flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then, 0.005g-0.02g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and dark conditions, the reaction system is kept undisturbed for 24 hours, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon coated hollow manganese ferrite nano composite material;

through detection, the saturation magnetization intensity of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 29.7-35.6 emu/g.

Preferably, the mixed acid solution in the fifth step is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3.

Preferably, the dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

Preferably, the high-pressure reaction kettle in the second step and the high-pressure reaction kettle in the fifth step is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

Preferably, the molar concentration of the glucopyranose solution in the step three is 0.15 mol/L.

Preferably, the molar concentration of the gamma cyclodextrin solution in the fourth step is 0.04 mol/L.

Preferably, in the mixed aqueous solution of copper acetate and pyridine in the sixth step, the molar concentration of copper acetate is 0.01mol/L, and the molar concentration of pyridine is 0.25 mol/L.

The chemical equation in the second step of the method is as follows:

Mn₂++2Fe₃++8OH-＝MnFe₂O₄+4H₂O

the chemical equation in the sixth step of the method is as follows:

firstly, synthesizing carbon-coated hollow manganese ferrite nanoparticles serving as a precursor by using a solvothermal method, then vacuumizing a flask filled with the carbon-coated hollow manganese ferrite nanoparticles to enable negative pressure to be formed inside the carbon-coated hollow manganese ferrite nanoparticles, and soaking the carbon-coated hollow manganese ferrite nanoparticles into a mixed aqueous solution of copper acetate and pyridine to enable the mixed aqueous solution of copper acetate and pyridine to enter the flask; pouring out the redundant solution under magnetic separation to only retain the nano material; then, injecting a dichloromethane solution of hexaethynylbenzene into the reaction system under the conditions of argon and darkness to form a thermodynamically stable system; and finally, extracting a product by using a magnet, washing the product by using absolute ethyl alcohol, and drying to obtain the graphite alkyne/hollow manganese ferrite nano photocatalyst composite material.

The graphite alkyne/hollow manganese ferrite nano-particles prepared by the method have huge specific surface area, and the hollow structure can enable photons to be reflected and scattered for many times, so that the absorption utilization rate of the light can be effectively improved.

The graphite alkyne/hollow manganese ferrite nano-particles prepared by the method have good separation and recovery characteristics, and the recovery of the photocatalyst is easily realized through an external magnetic field.

The graphite alkyne/hollow manganese ferrite nano-particle prepared by the method skillfully utilizes the cavity of the magnetic hollow manganese ferrite nano-particle, effectively solves the problem of compounding the hollow manganese ferrite and the graphite alkyne, shortens the process period, reduces the cost and is beneficial to industrial production.

Drawings

FIG. 1 is an XRD pattern of a magnetic-response graphitic carbon-coated hollow manganese ferrite nanocomposite;

FIG. 2 is a VSM test analysis of a magnetically responsive graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite;

FIG. 3 is an SEM photograph of a magnetically responsive graphitic alkyne-coated carbon-coated hollow manganese ferrite nanocomposite;

fig. 4 is a photo-catalytic performance test chart of the magnetic response graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite.

Detailed Description

The present invention is described in further detail below with reference to specific examples and verification of the products of the examples.

Example 1

A preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing filter residue with deionized water/ethanol for many times, and vacuum drying the filter residue at 60 ℃ for 8 hours to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of a glucopyranose solution with the molar concentration of 0.15mol/L, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the glucopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution with the molar concentration of 0.04mol/L, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, filtering to obtain polymer nanoparticles of the glucopyranose and the manganese ferrite, uniformly dispersing the polymer nanoparticles of the glucopyranose and the manganese ferrite into a mixed acid solution, soaking for 8 hours, washing and drying to obtain carbon-coated hollow manganese ferrite nanoparticles;

the mixed acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a 50mL round-bottom flask, vacuumizing the round-bottom flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the round-bottom flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then 0.005g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and darkness, the reaction system is kept for 24 hours without interference, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon-coated hollow manganese ferrite nano composite material;

in the mixed aqueous solution of the copper acetate and the pyridine, the molar concentration of the copper acetate is 0.01mol/L, and the molar concentration of the pyridine is 0.25 mol/L.

Through detection, the saturation magnetization intensity of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 35.6 emu/g.

The dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane solution, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

The high-pressure reaction kettle is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

Example 2

A preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing filter residue with deionized water/ethanol for many times, and vacuum drying the filter residue at 60 ℃ for 8 hours to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of a glucopyranose solution with the molar concentration of 0.15mol/L, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the glucopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution with the molar concentration of 0.04mol/L, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, filtering to obtain polymer nanoparticles of the glucopyranose and the manganese ferrite, uniformly dispersing the polymer nanoparticles of the glucopyranose and the manganese ferrite into a mixed acid solution, soaking for 8 hours, washing and drying to obtain carbon-coated hollow manganese ferrite nanoparticles;

the mixed acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a 50mL round-bottom flask, vacuumizing the round-bottom flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the round-bottom flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then 0.005g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and darkness, the reaction system is kept for 24 hours without interference, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon-coated hollow manganese ferrite nano composite material;

in the mixed aqueous solution of the copper acetate and the pyridine, the molar concentration of the copper acetate is 0.02mol/L, and the molar concentration of the pyridine is 0.5 mol/L.

Through detection, the saturation magnetization intensity of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 33.7 emu/g.

The dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane solution, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

The high-pressure reaction kettle is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

Example 3

A preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing filter residue with deionized water/ethanol for many times, and vacuum drying the filter residue at 60 ℃ for 8 hours to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of a glucopyranose solution with the molar concentration of 0.15mol/L, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the glucopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution with the molar concentration of 0.04mol/L, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, filtering to obtain polymer nanoparticles of the glucopyranose and the manganese ferrite, uniformly dispersing the polymer nanoparticles of the glucopyranose and the manganese ferrite into a mixed acid solution, soaking for 8 hours, washing and drying to obtain carbon-coated hollow manganese ferrite nanoparticles;

the mixed acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a 50mL round-bottom flask, vacuumizing the round-bottom flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the round-bottom flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then 0.005g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and darkness, the reaction system is kept for 24 hours without interference, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon-coated hollow manganese ferrite nano composite material;

in the mixed aqueous solution of the copper acetate and the pyridine, the molar concentration of the copper acetate is 0.03mol/L, and the molar concentration of the pyridine is 0.75 mol/L.

Through detection, the saturation magnetization intensity of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 31.1 emu/g.

The dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane solution, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

The high-pressure reaction kettle is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

Example 4

A preparation method of a graphite alkyne/hollow manganese ferrite nano photocatalyst comprises the following steps:

step one, dissolving 0.49g of manganese chloride and 1.35g of ferric trichloride in 40mL of glycol solution, and obtaining uniformly dispersed suspension emulsion under the action of ultrasound;

step two, mixing 3.6g of sodium acetate and 1.2g of polyethylene glycol into the suspension emulsion prepared in the step one, stirring for 30min, transferring the mixture into a high-pressure reaction kettle, and keeping the temperature at 200 ℃ for 8 h; cooling the solution to room temperature after the reaction is finished, filtering, repeatedly washing filter residue with deionized water/ethanol for many times, and vacuum drying the filter residue at 60 ℃ for 8 hours to obtain black manganese ferrite nano powder;

step three, taking 0.8g of the manganese ferrite nanopowder prepared in the step two, uniformly dispersing the manganese ferrite nanopowder into 0.36g of a glucopyranose solution with the molar concentration of 0.15mol/L, performing ultrasonic dispersion for 1h, heating to 60 ℃, keeping the temperature for 2h, and performing a first thermal polymerization reaction to form a polymer of the glucopyranose and the manganese ferrite;

step four, uniformly dispersing the polymer of the glucopyranose and the manganese ferrite prepared in the step two into 1.03g of gamma cyclodextrin solution with the molar concentration of 0.04mol/L, ultrasonically dispersing for 1h, heating to 60 ℃, keeping for 2h, and carrying out a second thermal polymerization reaction to form pores on the polymer particles of the glucopyranose and the manganese ferrite;

transferring the solution after the secondary thermal polymerization reaction to a high-pressure reaction kettle, keeping the solution at 150 ℃ for 2 hours, and performing carbonization reaction; after the reaction is finished, cooling the solution to room temperature, filtering to obtain polymer nanoparticles of the glucopyranose and the manganese ferrite, uniformly dispersing the polymer nanoparticles of the glucopyranose and the manganese ferrite into a mixed acid solution, soaking for 8 hours, washing and drying to obtain carbon-coated hollow manganese ferrite nanoparticles;

the mixed acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the mass ratio of the concentrated sulfuric acid to the concentrated nitric acid is 5: 3;

step six, putting 0.5g of the carbon-coated hollow manganese ferrite nanoparticles prepared in the step five into a 50mL round-bottom flask, vacuumizing the round-bottom flask to form a negative pressure environment in the flask, injecting 10mL of mixed aqueous solution of copper acetate and pyridine into the round-bottom flask, soaking the carbon-coated hollow manganese ferrite nanoparticles for 10 hours, magnetically separating the carbon-coated hollow manganese ferrite nanoparticles, and pouring off the redundant solution in the flask; then 0.005g of methylene chloride solution of hexaethynylbenzene is injected into the flask under the protection of argon and darkness, the reaction system is kept for 24 hours without interference, and after the reaction is finished, criss-cross graphite alkyne walls grow on the surfaces of the carbon-coated hollow manganese ferrite nano particles; removing an organic phase by using a magnet for adsorption, washing and drying to obtain a graphite alkyne coated carbon-coated hollow manganese ferrite nano composite material;

in the mixed aqueous solution of the copper acetate and the pyridine, the molar concentration of the copper acetate is 0.04mol/L, and the molar concentration of the pyridine is 1.0 mol/L.

Through detection, the saturation magnetization intensity of the prepared graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite is 29.7 emu/g.

The dichloromethane solution of hexaethynylbenzene in the sixth step is a solution formed by dissolving hexaethynylbenzene in dichloromethane solution, and the molar concentration of the dichloromethane solution of hexaethynylbenzene is 0.1 mM.

The high-pressure reaction kettle is a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining.

The structural performance of the photocatalytic nanocomposite material prepared by the invention is analyzed and illustrated by using the graphdine/hollow manganese ferrite nano photocatalyst prepared in example 1 as a sample through X-ray diffraction (XRD), a Vibration Sample Magnetometer (VSM), a scanning electron microscope SEM, a photocatalytic test and the like.

1. XRD analysis

The XRD patterns of fig. 1 show the chemical composition and crystal structure of manganese ferrite nanopowder, carbon-coated hollow manganese ferrite nanoparticles and graphitic alkyne-coated carbon-coated hollow manganese ferrite nanocomposite. Manganese ferrite nanopowder showed characteristic diffraction peaks (corresponding to standard card 10-0319) at 2 θ of 29.98 ° (220), 35.38 ° (311), 43.08 ° (400), 56.98 ° (511) and 62.54 ° (440). Narrow peaks, indicating high crystallinity of the manganese ferrite nanopowder nanoparticles. Because the surface of the manganese ferrite nano powder is completely covered by the carbon layer, the diffraction peak intensity of the carbon-coated hollow manganese ferrite nano particle is not as sharp as that of the manganese ferrite nano powder, and the introduction of the carbon layer does not change the phase composition of the manganese ferrite nano powder. Pure graphyne shows an obvious characteristic peak of carbon (2 theta is 21.49 degrees), and different from the amorphous carbon coating (2 theta is 18.25 degrees), the graphyne-coated carbon-coated hollow manganese ferrite nano composite material loaded by the graphyne shows a relatively obvious characteristic peak of the graphyne carbon, which indicates the successful loading of the graphyne.

2. VSM analysis

Fig. 2 shows that all magnetization curves have a typical S-shape under an applied magnetic field, indicating that they are superparamagnetic materials. The manganese ferrite nanopowder showed a significantly symmetrical hysteresis loop with a saturation magnetization of about 81.1 emu/g. Due to the introduction of the non-magnetic carbon layer and the graphite alkyne layer, the saturation magnetization values of the carbon-coated hollow manganese ferrite nanoparticles (49.9emu/g) and the graphite alkyne-coated carbon-coated hollow manganese ferrite nanocomposite (35.6emu/g) were slightly lower than that of the manganese ferrite nanopowder. Nevertheless, the superparamagnetism of the hollow manganese ferrite nanocomposite coated by the graphdiyne-coated carbon can still be easily separated from the solution by an external magnetic field, and the separation and the recovery are convenient in practical application.

Uniformly dispersing the hollow manganese ferrite nanocomposite coated with the graphdiyne-coated carbon in a container filled with water to form turbid liquid; then the magnet was placed on the outside of the vessel and it was found that the composite material in the suspension was directionally moved towards the magnet under the action of the applied magnetic field and was all moved towards the magnet over 1 min. The composite material still has good magnetic response performance, can be successfully extracted and separated under the action of an external magnetic field, and realizes the recovery and the reuse of the magnetic response photocatalytic composite material.

3. SEM analysis

FIG. 3 shows that the thickness of the graphdine prepared by the present study is less than 50nm (figure r), and the graphdine has both flexibility and continuity and is a novel material in the carbon family. MnFe₂O₄(FIG. 2) is a spherical particle with a diameter of about 200nm, and the surface of the spherical particle is formed by stacking clusters smaller than 50 nm. MnFe₂O₄After the spherical nano particles are subjected to double coating, carbonization and mixed acid etching by glucopyranose and gamma-CD, the original solid structure is changed intoHollow structure (diagram c). From the graph iv, it can be seen that, compared with the carbon-coated hollow manganese ferrite nanoparticles, the outer surface of the graphdine-coated carbon-coated hollow manganese ferrite nanocomposite grows a large number of criss-cross flaky substances, so that the whole composite material looks like a flower-like structure, which is strong evidence that graphdine is successfully loaded on the surface of the carbon-coated hollow manganese ferrite nanoparticles.

4. Photocatalytic Performance test

Testing an instrument: utilizes XPA-7 type photocatalytic reactor, and produces products from Nanjing xu Jiang electromechanical plant.

The test method comprises the following steps: the photocatalytic performance of the synthesized catalyst was evaluated by the degradation of tetracycline hydrochloride (TCH) under visible light and near infrared light irradiation. A300 w Xe lamp (Medium Angle brocade source, cell-hxf 300) was used as the light source, fitted with cutting filters at 420nm and 760 nm. 30mg of the photocatalyst was placed in 50ml of a tetracycline hydrochloride (TCH) solution at a concentration of 10 mg/l. Before irradiation, stirring was continued in the dark for 30min to reach equilibrium of adsorption and desorption. After centrifugation 3ml of suspension were collected at certain irradiation intervals to remove residual particles. The relative concentration of residual tetracycline hydrochloride (TCH) was determined by UV-visible spectrophotometer at the maximum absorption peak (288 nm). The apparent rate constant (k) of tetracycline hydrochloride degradation is calculated as follows:

wherein k is the apparent rate constant of tetracycline hydrochloride degradation, t is the reaction time, C₀The absorbance of tetracycline hydrochloride before photocatalytic reaction; ct is the absorbance of tetracycline hydrochloride after the photocatalytic reaction.

Fig. 4 is a graph showing that various photocatalytic experiments were performed by degrading tetracycline hydrochloride (TCH) in order to verify the photocatalytic activity of each sample. Under the dark condition (before 30 minutes), the degradation effects of the blank control group and the pure manganese ferrite nano powder are not very different, and the degradation rates of tetracycline hydrochloride (TCH) are all lower than 1%, which indicates that the prepared solid manganese ferrite nano powder nanoparticles have poor adsorption performance on tetracycline hydrochloride (TCH); the carbon-coated hollow manganese ferrite nano-particles and the graphite alkyne-coated carbon-coated hollow manganese ferrite nano-composite material benefit from a hollow mesoporous structure, have a certain adsorption effect on tetracycline hydrochloride (TCH), and have a degradation rate approaching 5% under a dark condition. After xenon lamp irradiation, the degradation rate of the pure manganese ferrite nanopowder is gradually increased, and the degradation rate is obviously changed compared with that of a blank control group. The degradation rate after 90 minutes is about 9%, which may be due to the weak absorption capacity of the manganese ferrite nanopowder to visible light, whereas the degradation to tetracycline hydrochloride (TCH) mainly results from the weak oxidation capacity of the manganese ferrite nanopowder. For the carbon-coated hollow manganese ferrite nano-particles, the degradation rate of TCH is about 55.9% after 90 minutes; after the graphdine is loaded, the degradation rate of tetracycline hydrochloride (TCH) is about 89%, and the degradation rate of the hollow manganese ferrite nano-particles coated by pure carbon is increased by 33.1%; after 120 minutes, the degradation rate of the hollow manganese ferrite nanocomposite coated with the graphdiyne-coated carbon to tetracycline hydrochloride (TCH) is approximately 95%.