Preparation method and antibacterial application of indium zinc sulfide and nitrogen-doped titanium oxide composite material

Abstract

The invention relates to a preparation method and antibacterial application of an indium zinc sulfide and nitrogen-doped titanium oxide composite material. The preparation method comprises the following steps: preparing nitrogen-doped titanium oxide; and preparing the indium zinc sulfide / nitrogen-doped titanium oxide composite material. The preparation method has the beneficial effects that by doping the nitrogen element, the absorption spectrum range of single titanium dioxide is effectively expanded, particularly the response to visible light is enhanced, and the antibacterial efficiency of the titanium dioxide under a natural light condition is improved; meanwhile, through compounding with ZnIn2S4, light absorption is further improved, meanwhile, heterojunction is formed, a strong built-in electric field promotes carrier separation, and the antibacterial performance is enhanced; the energy band structure of titanium oxide is regulated and controlled through nitrogen atom doping, and the spectral response range is expanded; meanwhile, a built-in electric field is constructed through in-situ modification of indium zinc sulfide, and interface charge transfer is promoted, so that the carrier separation efficiency is effectively improved, the antibacterial performance of the composite material under natural light irradiation is remarkably improved, and the light absorption performance is improved in an ultraviolet-visible region.

Description

Technical Field

[0001] The present invention belongs to the technical field of antibacterial materials, and particularly relates to a preparation method and antibacterial application of a composite material of indium zinc sulfide and nitrogen-doped titanium oxide. Background Art

[0002] With the growth of the global population and the acceleration of the urbanization process, problems such as environmental pollution, the spread of pathogenic microorganisms, and resource shortage have become increasingly serious, and global public health is facing severe challenges. The spread of infectious diseases, especially infections caused by bacteria, remains one of the main factors threatening human life and health. Pneumonia, tuberculosis, urinary tract infections, wound infections, etc. are still the most common types of infections in hospitals in various countries.

[0003] Traditional antibiotics and disinfection methods have not effectively curbed the spread of bacteria in many cases. Especially due to the emergence of multi-drug resistant bacteria, the treatment has become more complex and difficult. Therefore, the development of new antibacterial materials has become an important way to solve these problems. Antibacterial materials, especially those with broad-spectrum bactericidal functions, can be used as a new technical means to address bacterial infections and the resulting public health challenges. As an emerging antibacterial technology, photocatalytic semiconductor materials have shown broad application prospects.

[0004] The basic principle of photocatalytic semiconductor antibacterial technology is based on the fact that semiconductor materials can generate electron-hole pairs under the action of light. These excited electrons and holes can react with surrounding water and oxygen molecules to generate reactive oxygen species (ROS), such as superoxide anion (O 2 · - ), hydroxyl radical (·OH), singlet oxygen ( 1 O 2 ), etc. These reactive oxygen species have strong oxidizing properties and can destroy the membrane structure of bacterial cells, degrade DNA and proteins inside bacterial cells, thereby achieving the bactericidal effect. CN201810066179.9 proposes a titanium oxide-based photocatalytic antibacterial material, which relies on the photocatalytic properties of single titanium oxide and has problems such as low carrier separation efficiency and poor visible light response.

[0005] Although photocatalytic semiconductor materials have shown great potential in the antibacterial field, they still face some challenges in practical applications: The main problem is the low photocatalytic efficiency. Many photocatalytic materials mainly work under ultraviolet light, and the radiation energy of ultraviolet light is relatively low, and the energy of natural light is also limited.

[0006] Therefore, how to improve the catalytic efficiency of materials in visible light or even low-light environments remains an important research direction. Summary of the Invention

[0007] The object of the present invention is to overcome the deficiencies in the prior art and provide a preparation method and antibacterial application of indium zinc sulfide and nitrogen-doped titanium oxide composite materials.

[0008] The preparation method of this indium zinc sulfide and nitrogen-doped titanium oxide composite material includes the following steps:

[0009] Step 1, preparation of nitrogen-doped titanium oxide: Grind and mix TiO 2 and urea evenly, then transfer them to a vacuum tube furnace, keep them warm for a period of time under a protective atmosphere, cool them to room temperature with the furnace, centrifuge and wash the obtained powder, and dry it to obtain N-TiO 2 ;

[0010] Step 2, preparation of indium zinc sulfide / nitrogen-doped titanium oxide composite material: Add N-TiO 2 to an aqueous glycerol solution, then add a Zn source, an In source, and thioacetamide, stir evenly, keep them warm in an oil bath for a certain time, centrifuge and wash the precipitate, and dry it to obtain ZnIn 2 S 4 / N-TiO 2 composite material.

[0011] Preferably, in step 1, the mass ratio of TiO 2 to urea is 1:5 to 15.

[0012] Preferably, in step 2, the volume ratio of glycerol to water in the aqueous glycerol solution is 1:3 to 5.

[0013] Preferably, in step 2, the Zn source is ZnCl 2 or Zn(NO 3 ) 2 , the In source is InCl 3 or InCl 3 ·4H 2 O; the molar ratio of the Zn source, the In source, and thioacetamide is 1:0.5 to 2:4.

[0014] Preferably, in step 2, the mass ratio of N-TiO 2 to ZnIn 2 S 4 is 1:5 to 15.

[0015] Preferably, in step 2, the temperature for heat preservation in the oil bath is 70 to 90 °C, and the heat preservation time is 1 to 3 h.

[0016] Preferably, in step 2, the centrifugal washing solvent is water or ethanol, and the number of washing times is 3 to 6 times.

[0017] The application of the indium zinc sulfide and nitrogen-doped titanium oxide composite material obtained by this method in the field of photocatalytic antibacterial.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1) By doping nitrogen elements, the present invention effectively expands the absorption spectrum range of single titanium dioxide, especially enhances its response to visible light, and improves its antibacterial efficiency under natural light conditions; at the same time, by compounding with ZnIn 2 S 4 Compound, further improving light absorption, forming a heterojunction at the same time, the strong built-in electric field promotes the separation of carriers, and enhances the antibacterial performance.

[0020] 2) The composite material obtained by the present invention has the advantages of low toxicity, low cost, strong broad-spectrum antibacterial property, and long-lasting antibacterial effect compared with the existing Ag ion antibacterial materials, copper-based antibacterial materials, and organic antibacterial materials on the market; compared with traditional semiconductor antibacterial materials such as TiO 2 and ZnO, it has the advantages of a wide light response range and high photogenerated charge separation efficiency, and can be applied to antibacterial disinfection in indoor and other living scenarios.

[0021] 3) The present invention regulates the energy band structure of titanium oxide by nitrogen atom doping, expands its spectral response range; at the same time, by in-situ modifying zinc indium sulfide to construct a built-in electric field, promoting interfacial charge transfer, thereby effectively improving the carrier separation efficiency, significantly enhancing the antibacterial performance of the composite material under natural light irradiation, and showing an increase in light absorption performance in the ultraviolet-visible region. Brief Description of the Drawings

[0022] Figure 1 is the X-ray diffraction pattern of ZIS / N-TiO 2 、N-TiO 2 and ZIS;

[0023] Figure 2 is the scanning electron micrograph of ZIS / N-TiO 2 prepared in Example 2 of the present invention;

[0024] Figure 3 is the ultraviolet-visible absorption spectrum of ZIS / N-TiO 2 、N-TiO 2 and ZIS;

[0025] Figure 4 is the antibacterial performance test result graph of ZIS / N-TiO 2 prepared in Example 2 of the present invention. Detailed Description of the Invention

[0026] The present invention will be further described below in conjunction with embodiments. The description of the following embodiments is only for helping to understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0027] Embodiment 2

[0028] As an embodiment, a preparation method of this indium zinc sulfide and nitrogen-doped titanium oxide composite material includes the following steps:

[0029] Step 1, prepare nitrogen-doped titanium oxide (N-TiO 2 )

[0030] Mix a certain amount of TiO 2 and urea by grinding evenly, and place them in a porcelain boat. TiO 2 is commercial TiO 2 or nano-TiO 2 prepared by a hydrothermal method; the mass ratio of TiO 2 to urea is 1:5-15.

[0031] Then transfer it to a vacuum tube furnace, keep it warm for a period of time under a protective atmosphere, and the protective atmosphere is argon or nitrogen. During the chemical vapor reaction process, the N dopant used is urea, which decomposes to produce ammonia gas under heating conditions, and the ammonia gas reacts with titanium dioxide to carry out chemical vapor deposition to make the N element doped into the titanium dioxide lattice.

[0032] Cool it to room temperature with the furnace, and obtain N-TiO 2 after centrifugal washing and drying of the obtained powder.

[0033] Step 2, prepare indium zinc sulfide / nitrogen-doped titanium oxide (ZnIn 2 S 4 / N-TiO 2 ) composite material

[0034] Add a certain amount of N-TiO 2 to the glycerol aqueous solution, and the volume ratio of glycerol to water in the glycerol aqueous solution is 1:3-5.

[0035] Then add Zn source, In source and thioacetamide (TAA), the Zn source is ZnCl 2 or Zn(NO 3 ) 2 , the In source is InCl 3 or InCl 3 ·4H 2 O; the molar ratio of Zn source, In source and TAA is 1:2:4.

[0036] After stirring evenly, keep it warm in an oil bath for a certain period of time. The temperature for heat preservation in the oil bath is 70-90 °C, and the heat preservation time is 1-3 h. Centrifuge and wash the precipitate. The solvent for centrifugal washing is water or ethanol, and the number of washing times is 3-6 times.

[0037] After drying, ZnIn 2 S 4 / N-TiO 2 composite material can be used in the field of photocatalytic antibacterial. The mass ratio of N-TiO 2 to ZnIn 2 S 4 is 1:5-15.

[0038] Example 2

[0039] As another example, this Example 2 is proposed on the basis of Example 1. A more specific preparation method of zinc indium sulfide and nitrogen-doped titanium dioxide composite material, abbreviated as ZIS / N-TiO 2 is as follows:

[0040] Step 1. Prepare nitrogen-doped titanium dioxide:

[0041] Mix 100 mg of titanium dioxide with 1 g of urea and grind them evenly. Place them in a porcelain boat and put it into a vacuum tube furnace. Under an argon atmosphere, heat it to 700 °C at a rate of 5 °C / min and keep it warm for 2 h, then cool it with the furnace. Wash the obtained powder 3 times with deionized water and ethanol, and vacuum dry it at 60 °C for 2 h to obtain nitrogen-doped titanium dioxide N-TiO 2 .

[0042] Step 2. Prepare nitrogen-doped titanium dioxide loaded with zinc indium sulfide

[0043] Take 10 mg of the N-TiO 2 obtained in Step 1 and place it in 100 mL of glycerol aqueous solution, glycerol: water = 1:4.

[0044] Add 273 mg of ZnCl 2 , 586 mg of InCl 3 ·4H 2 O and 300 mg of TAA to obtain a mixed solution. Put the mixed solution into an oil bath at 80 °C, stir and react for 2 h. Wash the obtained precipitate 3 times with deionized water and ethanol to obtain nitrogen-doped titanium dioxide loaded with zinc indium sulfide, that is, zinc indium sulfide / nitrogen-doped titanium dioxide ZnIn 2 S 4 / N-TiO 2 composite material.

[0045] During the chemical vapor reaction process, the N dopant used is urea, which decomposes to produce ammonia under heating conditions. The ammonia undergoes chemical vapor deposition with titanium dioxide, enabling the doping of N elements into the titanium dioxide lattice.

[0046] It should be noted that the same or similar parts in this embodiment and the first embodiment can be referred to each other and will not be elaborated in this application.

[0047] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0048] Comparative Example 1

[0049] As a comparative example, an N-TiO 2 material is prepared as follows:

[0050] 100 mg of titanium dioxide and 1 g of urea are mixed and ground evenly, placed in a porcelain boat and put into a vacuum tube furnace. Under an argon atmosphere, it is heated to 700 °C at a rate of 5 °C / min and held for 2 h. The obtained powder is washed 3 times with deionized water and ethanol, and vacuum dried at 60 °C for 2 h to obtain nitrogen-doped titanium dioxide (N-TiO 2 ).

[0051] Comparative Example 2

[0052] As another comparative example, a ZnIn 2 S 4 material is prepared as follows:

[0053] ZnCl 2 , InCl 3 ·4H 2 O and TAA are dissolved in 100 mL of glycerol aqueous solution according to a molar ratio of 1:2:4, and the glycerol concentration is 20 vol%. Then, the obtained mixed solution is placed in an oil bath at 80 °C and stirred for 2 h. After the reaction, it is filtered. The obtained precipitate is centrifugally washed 6 times with ethanol and deionized water, and then vacuum dried at 60 °C for 2 h to obtain zinc indium sulfide ZnIn 2 S 4 powder, abbreviated as ZIS.

[0054] The ZIS / N-TiO 2 composite material prepared in Example 2, the N-TiO 2 material prepared in Comparative Example 1, and the ZIS material prepared in Comparative Example 2 are respectively subjected to X-ray diffraction test, scanning electron microscope test, ultraviolet-visible light absorption spectrum, and antibacterial performance test:

[0055] I. X-ray diffraction test:

[0056] As Figure 1 shown, the XRD diffraction patterns of ZIS and N-TiO 2 correspond to the standard cards of hexagonal ZnIn 2 S 4 (JCPDS#65-2023) and anatase TiO 2 (JCPDS#65-5714), respectively. Diffraction peaks located at 47.2° and 25.3° can be observed in the XRD pattern of ZIS / N-TiO 2 , corresponding to the (110) crystal plane of ZIS and N-TiO 2 (101) crystal plane, respectively, proving the successful preparation of the composite material.

[0057] II. Scanning electron microscopy test:

[0058] The ZIS / N-TiO 2 prepared in Example 2 was tested by scanning electron microscopy (SEM).

[0059] As Figure 2 shown, ZIS / N-TiO 2 exhibits a morphology of composite thin and thick sheets, and the size of the sheets is several hundred nanometers.

[0060] III. Ultraviolet-visible absorption spectrum:

[0061] As Figure 3 shown, the absorption edge of N-TiO 2 is approximately at 400 nm. The defect states introduced by nitrogen doping result in an obvious tail absorption in the entire visible light region of 400 - 800 nm. The absorption edge of ZIS is approximately at 500 nm. After the two phases are combined, the sample shows an increase in light absorption performance in the ultraviolet-visible region, while showing performance between N-TiO 2 and ZIS in other regions, proving that the ZIS / N-TiO 2 material prepared by the method proposed in the present invention can achieve the superposition of the light absorption performances of ZIS and N-TiO 2 and obtain better light absorption performance.

[0062] IV. Antibacterial performance test:

[0063] The ZIS / N-TiO 2 prepared in Example 2 was tested for antibacterial performance.

[0064] Dilute the Escherichia coli bacterial solution to an appropriate multiple, then drop the diluted bacterial solution on the surface of the antibacterial material, and keep it for 5 minutes under dark conditions and light conditions respectively. Then, suck the bacterial solution drop on the coating surface and evenly apply it on the prepared agar plate, and place it in an incubator for heat preservation for 12 hours to ensure the growth of bacteria and the manifestation of antibacterial effect. After the cultivation, observe the number of colonies on the agar plate to judge the antibacterial performance. At the same time, set up a blank control group: drop the bacterial solution on the blank optical glass and test the antibacterial performance under two conditions of darkness and light.

[0065] As Figure 4 shown, a large number of bacterial colonies grew in the non-irradiated blank control group; the number of bacterial colonies in the irradiated blank control group decreased slightly because the ultraviolet light in the xenon lamp has a bactericidal effect. The number of bacterial colonies of the ZIS / N-TiO 2 sample under dark conditions was significantly lower than that of the blank group, while the number of bacterial colonies of the ZIS / N-TiO 2 sample under light conditions was the least, proving that the free radicals generated by light in the ZIS / N-TiO 2 material prepared by the method of the present invention have good bactericidal effects.

Claims

1. A method for preparing a composite material of indium zinc sulfide and nitrogen-doped titanium oxide, characterized in that: The following steps are involved: Step 1, preparation of nitrogen-doped titanium oxide: TiO2 and urea are ground and mixed evenly, then transferred to a vacuum tube furnace, kept warm for a period of time under a protective atmosphere, cooled to room temperature with the furnace, the obtained powder is centrifuged and washed, and dried to obtain N-TiO2; Step 2, preparation of indium zinc sulfide / nitrogen-doped titanium oxide composite material: N-TiO2 is added to the glycerol aqueous solution, and then the Zn source, In source and thioacetamide are added, stirred evenly, and kept warm in an oil bath for a certain period of time, the precipitate is centrifuged and washed, and the ZnIn2S4 / N-TiO2 composite material is obtained after drying.

2. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 1, the mass ratio of TiO2 to urea is 1:5-15.

3. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 2, the volume ratio of glycerol to water in the glycerol aqueous solution is 1:3-5.

4. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 2, the Zn source is ZnCl2 or Zn(NO3)2, and the In source is InCl3 or InCl3·4H2O; the molar ratio of the Zn source, the In source and thioacetamide is 1:0.5 to 2:

4.

5. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 2, the mass ratio of N-TiO2 and ZnIn2S4 is 1:5-15.

6. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 2, the temperature in the oil bath is kept at 70-90° C. for 1-3 hours.

7. The method for preparing the composite material of indium zinc sulfide and nitrogen-doped titanium oxide according to claim 1, characterized in that: In step 2, the centrifugal washing solvent is water or ethanol, and the washing times are 3 to 6 times.

8. Use of the composite material of indium zinc sulfide and nitrogen-doped titanium oxide obtained by the method according to claim 1 in the field of photocatalysis and antibacterial.

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