阅读说明：本技术 双发射石墨烯量子点/二氧化钛复合材料及其制备方法与应用 (Double-emission graphene quantum dot/titanium dioxide composite material and preparation method and application thereof ) 是由 李在均 江燕红 李瑞怡 徐鹏武 于 2021-01-27 设计创作，主要内容包括：本发明公开了一种双发射石墨烯量子点/二氧化钛复合材料及其制备方法与应用,所述制备方法包括以下步骤：将双发射石墨烯量子点和钛源于溶液中混合均匀,然后在100℃-200℃下反应5-15h；反应结束后,收集产物并洗涤、干燥,即得到所述双发射石墨烯量子点/二氧化钛复合材料；其中,所述双发射石墨烯量子点为采用丝氨酸和组氨酸功能化的石墨烯量子点。本发明制备的双发射石墨烯量子点/二氧化钛复合材料,具有紫外和可见光吸收的特性,可见光激发的石墨烯量子点不仅可以直接作用于细菌,还可以作为TiO-2的敏化剂,从而提高了材料的抗菌性能。(The invention discloses a dual-emission graphene quantum dot/titanium dioxide composite material and a preparation method and application thereof, wherein the preparation method comprises the following steps: uniformly mixing the dual-emission graphene quantum dots and the titanium source in a solution, and then reacting for 5-15h at 100-200 ℃; after the reaction is finished, collecting a product, washing and drying to obtain the dual-emission graphene quantum dot/titanium dioxide composite material; the double-emission graphene quantum dot is a graphene quantum dot functionalized by adopting serine and histidine. The dual-emission graphene quantum dot/titanium dioxide composite material prepared by the invention has the characteristics of ultraviolet and visible light absorption, and the graphene quantum dot excited by visible light can not only directly act on bacteria, but also be used as TiO 2 So as to improve the quality of the materialThe antibacterial property of the material.)

1. A preparation method of a dual-emission graphene quantum dot/titanium dioxide composite material is characterized by comprising the following steps:

uniformly mixing the dual-emission graphene quantum dots and the titanium source in a solution, and then reacting for 5-15h at 100-200 ℃; after the reaction is finished, collecting a product, washing and drying to obtain the dual-emission graphene quantum dot/titanium dioxide composite material;

the double-emission graphene quantum dot is a graphene quantum dot functionalized by adopting serine and histidine.

2. The method for preparing the dual-emission graphene quantum dot/titanium dioxide composite material as claimed in claim 1, wherein the dual-emission graphene quantum dot is prepared by adopting citric acid as a carbon source and serine and histidine as functionalizing agents through a pyrolysis reaction.

3. The method for preparing a dual-emission graphene quantum dot/titanium dioxide composite material according to claim 2, wherein the method for preparing the dual-emission graphene quantum dot comprises the following steps:

dissolving citric acid, histidine and serine in water, uniformly mixing, and then pyrolyzing at the temperature of 150-250 ℃ for 0.5-5h to obtain the dual-emission graphene quantum dot.

4. The method for preparing the dual-emission graphene quantum dot/titanium dioxide composite material of claim 3, wherein the molar ratio of the citric acid to the histidine to the serine is 1 (0.5-1) to (0.05-1).

5. The preparation method of the dual-emission graphene quantum dot/titanium dioxide composite material as claimed in claim 3, wherein after the reaction is finished, a 0.22 μm microporous filter membrane is used for suction filtration to remove larger particles, a dialysis bag with a molecular weight cut-off of 3kDa is used for dialysis in ultrapure water for 24h to remove unreacted citric acid, serine and histidine, and then freeze drying is carried out to obtain the dual-emission graphene quantum dot solid sample.

6. The method of claim 1, wherein the titanium source is butyl titanate.

7. The method for preparing the dual-emission graphene quantum dot/titanium dioxide composite material as claimed in claim 1, wherein the product is collected and washed with absolute ethanol.

8. The method of claim 1, wherein the drying temperature is 60 ℃.

9. The dual-emission graphene quantum dot/titanium dioxide composite material prepared according to the method of any one of claims 1 to 8.

10. Use of the dual emission graphene quantum dot/titanium dioxide composite material of claim 9 as an antimicrobial agent.

Technical Field

The invention relates to the technical field of composite materials, in particular to a dual-emission graphene quantum dot/titanium dioxide composite material and a preparation method and application thereof.

Background

In recent years, microbial and pathogenic contamination has become a major global concern, and has a serious impact on human health and safety. With the increasing variety and quantity of antibacterial products, the drug resistance of microorganisms is increasing, and the demand of people for antibacterial agents is also increasing. Therefore, the development of a novel complex antibacterial agent having high efficacy, safety and durability to cope with the increasing market demand is imperative.

Titanium dioxide (TiO)₂) Due to their unique optical, electrical and chemical properties, they are widely used in the fields of electronics, optics, medicine, etc. The application of the nano titanium dioxide film in the aspects of bacteriostasis, cell growth, differentiation and the like is also widely reported. TiO 2₂Are commonly used as UV preservatives in many products, such as cosmetics, fibers and paints. TiO 2₂There are many advantages such as in photocatalysis and its low cost, availability, low toxicity and chemical stability. However pure TiO₂Nanomaterials have their inherent disadvantages such as large binding energies, recombination of charge carriers and different distribution profiles in solution. In addition, only a small amount of active oxygen is generated under the irradiation of ultraviolet rays, and only weak antibacterial activity can be generated. Thus pure TiO₂Should be further enhanced and improved.

Graphene Quantum Dots (GQDs) are widely concerned by people in the past few years, and the GQDs as a novel multifunctional carbon nano material has wide application prospects in chemical sensing, biological imaging, drug delivery, photodynamic therapy, photocatalysis, photodynamic therapy and the like, and also has the advantages of good water solubility, biocompatibility, low toxicity, redox, luminescence and the like. In addition, they have up-and down-converting Photoluminescence (PL) and electron accepting and transporting properties. GQD has good hydrophilicity due to its surface having abundant oxygen-containing groups, and can form a complex through a functional group to be firmly bonded to other materials. TiO 2₂Combination with GQDs may be desirable materials that yield excellent photocatalytic activity to facilitate charge separation and transport.

Disclosure of Invention

The invention aims to solve the technical problem of providing a dual-emission graphene quantum dot/titanium dioxide composite material, wherein serine histidine functionalized graphene quantum dots are added in the preparation process of the composite material, so that the antibacterial performance of titanium dioxide is improved, and the antibacterial effect is stronger and more durable than that of a single titanium dioxide nano material.

In order to solve the technical problems, the invention provides the following technical scheme:

in a first aspect, the invention provides a preparation method of a dual-emission graphene quantum dot/titanium dioxide composite material, which comprises the following steps:

uniformly mixing the dual-emission graphene quantum dots and the titanium source in a solution, and then reacting for 5-15h at 100-200 ℃; after the reaction is finished, collecting a product, washing and drying to obtain the dual-emission graphene quantum dot/titanium dioxide composite material;

the double-emission graphene quantum dot is a graphene quantum dot functionalized by adopting serine and histidine.

Further, the dual-emission graphene quantum dot is prepared by adopting citric acid as a carbon source and serine and histidine as functional reagents through a pyrolysis reaction.

Further, the preparation method of the dual-emission graphene quantum dot comprises the following steps:

dissolving citric acid, histidine and serine in water, uniformly mixing, and then reacting at the temperature of 150-250 ℃ for 0.5-5h to obtain the dual-emission graphene quantum dot.

Further, the molar ratio of the citric acid to the histidine to the serine is 1 (0.5-1) to 0.05-1.

Further, after the reaction is finished, filtering the solution by using a 0.22-micron microporous filter membrane to remove larger particles, dialyzing the solution for 24 hours in ultrapure water by using a dialysis bag with the molecular weight cutoff of 3kDa to remove unreacted citric acid, serine and histidine, and then freeze-drying the solution to obtain the dual-emission graphene quantum dot solid sample.

Further, the titanium source is butyl titanate.

Further, after collecting the product, it was washed with anhydrous ethanol.

Further, the temperature of the drying was 60 ℃.

In a second aspect, the invention also provides the dual-emission graphene quantum dot/titanium dioxide composite material prepared by the method.

In a third aspect, the invention further provides an application of the dual-emission graphene quantum dot/titanium dioxide composite material as an antibacterial agent.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, the serine-histidine functionalized graphene quantum dots are added in the preparation process of the titanium dioxide nano material, so that the defect of pure TiO is overcome₂The inherent disadvantages of large binding energy, charge carrier recombination, weak antibacterial activity and the like of the nano material. The single serine functionalized graphene quantum dot and the single histidine functionalized graphene quantum dot have ultraviolet absorption and only one fluorescence emission peak, and the serine histidine functionalized graphene quantum dot has ultraviolet absorption and visible light absorption at the same time, so that the visible light-excited graphene quantum dot can not only directly act on bacteria, but also can be used as TiO₂The sensitizer improves the antibacterial performance of the material.

2. The graphene quantum dot composite titanium dioxide nano material prepared by the invention is simple in preparation method and good in antibacterial property.

Drawings

Fig. 1 is a synthesis schematic diagram of serine histidine functionalized graphene quantum dots.

Fig. 2 is an ultraviolet absorption diagram of serine histidine functionalized graphene quantum dots.

Fig. 3 is a fluorescence emission diagram of serine histidine functionalized graphene quantum dots.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The experimental methods used in the following examples are conventional methods unless otherwise specified, and materials, reagents and the like used therein are commercially available without otherwise specified.

Example 1

1. Weighing 1g of citric acid, putting the citric acid into a 25mL beaker, adding 0.1g of serine and 0.74g of histidine, adding 5mL of deionized water, stirring and dissolving, putting the mixture into an oven for pyrolysis at 180 ℃ for 3 hours, and synthesizing solid serine histidine functionalized graphene quantum dots (Ser-GQD-His).

2. The obtained solid Ser-GQD-His was dissolved in ultrapure water, and the pH of the solution was adjusted to 7 with sodium hydroxide solution. And (3) carrying out suction filtration by using a 0.22 mu m microporous filter membrane to remove larger particles, dialyzing in ultrapure water for 24h by using a dialysis bag with the molecular weight cutoff of 3kDa to remove unreacted citric acid, serine and histidine, and then carrying out freeze drying to obtain a Ser-GQD-His solid sample.

3. The invention adopts a hydrothermal method to synthesize the graphene quantum dot-titanium dioxide composite nanomaterial (Ser-GQ D-His/TiO)₂) Weighing 10mg of Ser-GQD-His powder in a beaker, dissolving in 10mL of ultrapure water, dissolving, and adjusting the pH to 7 to obtain a newly prepared Ser-GQD-His solution.

4. Adding the Ser-GQD-His solution into a beaker, dissolving 2mL of butyl titanate in 7.5mL of absolute ethyl alcohol, adding the butyl titanate suspension into the graphene quantum dot solution, and stirring for 30 minutes. Then the mixed solution is transferred to a high-pressure reaction kettle and reacts for 10 hours at the temperature of 150 ℃.

5. After the reaction is finished and the temperature is cooled to room temperature, absolute ethyl alcohol is used for filtering and washing for a plurality of times, and the obtained product is dried in a vacuum drying oven at the temperature of 60 ℃ to obtain Ser-GQD-His/TiO₂Solid body。

Example 2

1. Weighing 5g of citric acid, putting the citric acid into a 250mL beaker, adding 0.5g of serine and 3.7g of histidine, adding 10mL of deionized water, stirring and dissolving, putting the mixture into an oven for pyrolysis at 170 ℃ for 3 hours, and synthesizing solid serine histidine functionalized graphene quantum dots (Ser-GQD-His).

2. The obtained solid Ser-GQD-His was dissolved in ultrapure water, and the pH of the solution was adjusted to 7 with sodium hydroxide solution. And (3) carrying out suction filtration by using a 0.22 mu m microporous filter membrane to remove larger particles, dialyzing in ultrapure water for 24h by using a dialysis bag with the molecular weight cutoff of 3kDa to remove unreacted citric acid, serine and histidine, and then carrying out freeze drying to obtain a Ser-GQD-His solid sample.

3. The invention adopts a hydrothermal method to synthesize the graphene quantum dot-titanium dioxide composite nanomaterial (Ser-GQ D-His/TiO)₂) Weighing 15mg of Ser-GQD-His powder in a beaker, dissolving in 10mL of ultrapure water, dissolving, and adjusting the pH to 7 to obtain a newly prepared Ser-GQD-His solution.

4. Adding the Ser-GQD-His solution into a beaker, dissolving 1mL of butyl titanate in 9mL of absolute ethyl alcohol, adding the butyl titanate suspension into the graphene quantum dot solution, and stirring for 30 minutes. Then the mixed solution is transferred to a high-pressure reaction kettle and reacts for 8 hours at 160 ℃.

5. After the reaction is finished and the temperature is cooled to room temperature, absolute ethyl alcohol is used for filtering and washing for a plurality of times, and the obtained product is dried in a vacuum drying oven at the temperature of 60 ℃ to obtain Ser-GQD-His/TiO₂And (3) a solid.

Example 3

1. Weighing 10g of citric acid, putting the citric acid into a 500mL beaker, adding 0.5g of serine and 7.4g of histidine, adding 20mL of deionized water, stirring and dissolving, putting the mixture into an oven for pyrolysis at 200 ℃ for 2 hours, and synthesizing solid serine histidine functionalized graphene quantum dots (Ser-GQD-His).

2. The obtained solid Ser-GQD-His was dissolved in ultrapure water, and the pH of the solution was adjusted to 7 with sodium hydroxide solution. And (3) carrying out suction filtration by using a 0.22 mu m microporous filter membrane to remove larger particles, dialyzing in ultrapure water for 24h by using a dialysis bag with the molecular weight cutoff of 3kDa to remove unreacted citric acid, serine and histidine, and then carrying out freeze drying to obtain a Ser-GQD-His solid sample.

3. The invention adopts a hydrothermal method to synthesize the graphene quantum dot-titanium dioxide composite nanomaterial (Ser-GQ D-His/TiO)₂) Weighing 20mg of Ser-GQD-His powder in a beaker, dissolving in 10mL of ultrapure water, dissolving, and adjusting the pH to 7 to obtain a newly prepared Ser-GQD-His solution.

4. Adding the Ser-GQD-His solution into a beaker, dissolving 1.5mL of butyl titanate in 8mL of absolute ethyl alcohol, adding the butyl titanate suspension into the graphene quantum dot solution, and stirring for 30 minutes. Then the mixed solution is transferred to a high-pressure reaction kettle and reacts for 15 hours at the temperature of 130 ℃.

5. After the reaction is finished and the temperature is cooled to room temperature, absolute ethyl alcohol is used for filtering and washing for a plurality of times, and the obtained product is dried in a vacuum drying oven at the temperature of 60 ℃ to obtain Ser-GQD-His/TiO₂And (3) a solid.

Test of antibacterial Property

Testing of TiO₂Samples, Ser-GQD-His samples, and Ser-GQD-His/TiO samples of examples 1-3₂The bacteriostatic performance of the sample on staphylococcus aureus, escherichia coli, pseudomonas aeruginosa and candida albicans is shown in the following table.

The results in the above table indicate that₂Samples Ser-GQD-His/TiO samples from examples 1-3 compared to Ser-GQD-His samples₂The bacteriostatic performance of staphylococcus aureus, escherichia coli, pseudomonas aeruginosa and candida albicans is greatly improved. Ser-GQD-His/TiO₂The bacteriostatic rate of the antibacterial agent on staphylococcus aureus is more than or equal to 90 percent, the bacteriostatic rate on escherichia coli is more than or equal to 80 percent, the bacteriostatic rate on pseudomonas aeruginosa is more than or equal to 80 percent, and the bacteriostatic rate on candida albicans is more than or equal to 70 percent.

In conclusion, the method disclosed by the invention adopts serine-histidine to functionalize the graphene quantum dots, so that the defect of pure TiO is overcome₂The inherent defects of large binding energy, recombination of charge carriers, weak antibacterial activity and the like of the nano material are overcome, and the TiO content is improved₂Antibacterial property of the nano material.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.