Photocatalyst material with core-shell structure and preparation process thereof

Abstract

The invention relates to the technical field of photocatalysts, in particular to a shell-core structure photocatalyst material and a preparation process thereof. The shell-core structure photocatalyst material comprises titanium dioxide, an antibacterial composite layer and a silicon dioxide layer, the antibacterial composite layer and the silicon dioxide layer are sequentially coated, and raw materials of the antibacterial composite layer comprise ZIF-based quantum dots, gallic acid and zirconium phosphate. The shell-core structure photocatalyst material provided by the invention improves the problem of insufficient antibacterial performance in the prior art, and the prepared photocatalyst material has long-acting antibacterial performance and structural stability.

Description

Technical Field

[0001] This application relates to the field of photocatalysis technology, specifically to a core-shell structured photocatalyst material and its preparation process. Background Technology

[0002] Photocatalysts are photocatalytic semiconductor materials represented by nano-sized titanium dioxide. They can use ultraviolet light or light containing ultraviolet light, natural light and sunlight to purify the environment. They occupy an important position in the field of environmental governance and are widely used in sewage treatment, decomposition of organic matter, sterilization and mildew prevention, self-cleaning materials and other aspects.

[0003] The antibacterial effect of existing photocatalytic materials mainly relies on the indirect action of active free radicals generated by titanium dioxide photocatalysis. This lack of targeted antibacterial design results in low efficiency in killing bacteria and viruses, failing to meet the rapid antibacterial requirements in environmental remediation. Furthermore, conventional antibacterial improvement methods often employ physical mixing of antibacterial agents, leading to a loose bond between the antibacterial components and the photocatalyst core-shell structure. This loose bond makes them prone to detachment and loss during long-term use. Additionally, the highly active free radicals generated by titanium dioxide photocatalysis easily attack the antibacterial organic components, causing rapid degradation of antibacterial performance and preventing long-lasting antibacterial effects. Moreover, the use of large-diameter antibacterial particles or multi-component stacking to enhance antibacterial effects can lead to decreased light transmittance and increased haze in the photocatalyst coating, making it unsuitable for applications requiring transparent purification carriers.

[0004] There is an urgent need to develop a photocatalyst material that can balance high-efficiency antibacterial properties, long-term stability, and optical compatibility, so as to promote the practical application of photocatalyst materials in the field of environmental remediation materials. Summary of the Invention

[0005] To effectively address the aforementioned problems, this application provides a core-shell structured photocatalyst material and its preparation process, resulting in a photocatalyst material with high-efficiency antibacterial properties and long-term stability.

[0006] This application provides a core-shell structured photocatalyst material, which adopts the following technical solution: A core-shell structured photocatalyst material includes titanium dioxide, an antibacterial composite layer and a silica layer sequentially coated thereon; the raw materials of the antibacterial composite layer include ZIF-based quantum dots, gallic acid and zirconium phosphate.

[0007] Preferably, the mass ratio of ZIF-based quantum dots, gallic acid and zirconium phosphate is (5-8):(3-5):(2-4).

[0008] By adopting the above technical solution, the core-shell structure photocatalyst material of this application uses titanium dioxide as the core, is coated with an antibacterial composite layer, and then coated with a silicon dioxide layer on the outer layer. The problem of low antibacterial efficiency and insufficient long-term effect can be solved through the interaction of the core-shell structure.

[0009] The ZIF-based quantum dots in the antibacterial composite layer possess high dispersibility and high reactivity. They can effectively block direct contact with titanium dioxide nanoparticles through steric hindrance, enhancing the electrostatic repulsion between titanium dioxide nanoparticles. First, the uniformly distributed ZIF-based quantum dots themselves, as antibacterial components, form a dense and fully covered nano-antibacterial network on the surface of titanium dioxide, ensuring high efficiency and universality of contact with bacteria and promoting uniform distribution of titanium dioxide. This provides active sites with maximum exposure for photocatalytic reactions, significantly increasing the probability of contact with light, water, and pollutant molecules, thereby improving the photocatalytic activity of the photocatalytic material. On this basis, the introduction of gallic acid further enhances the contact antibacterial effect. Its phenolic hydroxyl groups can form hydrogen bonds with functional proteins and polysaccharides on bacterial cell membranes, disrupting membrane permeability, inhibiting bacterial metabolism, and producing a contact antibacterial effect. Furthermore, the layered structure of zirconium phosphate can physically capture bacteria, and its surface phosphate groups adsorb bacteria through electrostatic interactions, improving the contact efficiency between bacteria and antibacterial active sites. The interaction of these three factors enhances the antibacterial effect. In the antibacterial composite layer, the phosphate groups of zirconium phosphate form coordination bonds with the zinc ions of ZIF-based quantum dots, while the phenolic hydroxyl groups of gallic acid form a dense hydrogen bond network with the imidazole rings of the ZIF-based quantum dots and the phosphate groups of zirconium phosphate. This ensures uniform dispersion and tight binding of the antibacterial components, preventing aggregation and detachment, thereby further enhancing long-lasting antibacterial activity. Furthermore, the phenolic hydroxyl groups of gallic acid and the phosphate groups of zirconium phosphate form hydrogen bonds with the silanol groups on the silica surface, ensuring a firm coating of the silica layer. This guarantees stable adhesion of the antibacterial composite particles, protects the internal antibacterial components from loss, enhances structural stability, and prolongs the antibacterial duration. Zinc ions in ZIF-based quantum dots readily bind to and penetrate the polysaccharides on the surface of *E. coli*, causing targeted damage. The high dispersibility resulting from the confined framework further enhances the combined antibacterial efficiency against both *Staphylococcus aureus* and *E. coli*. The trihydroxyphenol structure of gallic acid exhibits strong polarity and reactivity, readily forming hydrogen bonds with the abundant protein amino groups on the surface of *Staphylococcus aureus* and penetrating the bacteria. The layered mesoporous structure of zirconium phosphate allows its pore size to be adapted to the size of *Staphylococcus aureus* cells, enabling efficient capture through physical sieving. Furthermore, its negatively charged phosphate groups create adsorption properties, adsorbing the strongly negatively charged surface of *E. coli*, achieving localized enrichment of *E. coli*. In addition, the size of ZIF-based quantum dots, zirconium phosphate, and the molecular-level characteristics of gallic acid are all much smaller than the wavelength of visible light, reducing light scattering. The small refractive index gradient between layers further reduces interfacial reflection loss, ensuring the continuous photocatalytic and photoactivated antibacterial functions of the core-shell structure photocatalyst material.

[0010] In one specific feasible implementation, the method for preparing ZIF-based quantum dots includes the following steps: dissolving Zn(NO3)2·6H2O in water to obtain solution A, dissolving 2-methylimidazole in water to obtain solution B, adding solution B dropwise to solution A, stirring at 20-30℃ for 25-35 min, centrifuging and washing, vacuum drying at 65-75℃ for 10-14 h to obtain ZIF-8 nanoparticle precursor, and then calcining at 280-320℃ for 1.5-2.5 h to obtain ZIF-based quantum dots.

[0011] Preferably, the mass ratio of Zn(NO3)2·6H2O to 2-methylimidazole is (1.7-1.9):1.

[0012] By employing the above technical solution, a well-structured ZIF-8 nanoparticle precursor is formed through a coordination reaction. The raw material ratio in this application ensures the coordination reaction proceeds fully, avoiding the possibility of an excessive amount of any single raw material leading to an irregular precursor structure, which would affect the long-term stability of the core-shell structure photocatalyst material. Calcination treatment allows the ZIF-8 precursor to inhibit the growth and aggregation of zinc oxide particles through spatial confinement, thereby maintaining its high dispersibility and activity at the quantum dot scale. This not only guarantees the properties of zinc oxide but also improves the dispersibility and lifespan of the quantum dots through the stabilizing effect of the framework, enabling it to better interact with gallic acid and zirconium phosphate for antibacterial activity, while also adapting to the overall core-shell structure. Therefore, an excessive amount of 2-methylimidazole can lead to an overly dense precursor framework structure and reduced porosity. During subsequent calcination, the organic ligands may not fully decompose, potentially causing local aggregation of zinc oxide particles, reducing their dispersibility, and thus affecting the synergistic antibacterial effect with gallic acid and zirconium phosphate. When the 2-methylimidazole content is too low, some zinc ions cannot fully participate in the coordination reaction, and the uncoordinated zinc ions will lead to irregular precursor structure. The residual zinc ions may also excessively bind with the phosphate groups of zirconium phosphate in the antibacterial composite layer, affecting the adsorption and capture capacity of zirconium phosphate for bacteria, disrupting the balance of the three in antibacterial action, and ultimately reducing the antibacterial efficiency and stability of the entire core-shell structure photocatalyst material.

[0013] In one specific feasible implementation, the method for preparing zirconium phosphate includes: dissolving ZrOCl2·8H2O in water, adjusting the pH value to 0.8-1.2 with hydrochloric acid to obtain solution C, dissolving phosphoric acid in water to obtain solution D, adding solution D dropwise to solution C, stirring for 0.8-1.2 h, transferring to a reaction vessel, reacting at 170-190℃ for 22-26 h, centrifuging, washing, drying, and then calcining at 380-420℃ for 2.5-3.5 h.

[0014] Preferably, the mass ratio of ZrOCl2·8H2O to phosphoric acid is (1.8-2.2):1.

[0015] By adopting the above technical solution, a well-structured layered mesoporous zirconium phosphate is formed, providing ample space for bacterial capture. Subsequent calcination further enhances the structural stability of zirconium phosphate, preventing structural collapse during use. When the ZrOCl2·8H2O content is too low, excessive phosphate ions interfere with the orderly arrangement of the layered structure, resulting in uneven mesopore size distribution, decreased porosity, weakened physical capture and electrostatic adsorption capabilities for bacteria, and reduced antibacterial performance. Conversely, if the ZrOCl2·8H2O content is too high, unreacted zirconium ions adhere to the zirconium phosphate surface, blocking mesoporous channels, reducing effective adsorption sites, and leading to particle aggregation. This disrupts the dispersibility of zirconium phosphate, preventing its uniform distribution within the antibacterial composite layer, reducing contact efficiency with ZIF-based quantum dots and gallic acid, and ultimately affecting the overall stability of the antibacterial performance.

[0016] Secondly, this application provides a preparation process for a core-shell structured photocatalyst material, employing the following technical solution: A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) dissolving tetrabutyl titanate in ethanol, stirring evenly, adding hydrochloric acid and water, stirring at 20-30℃ for 10-14h to form titanium dioxide raw material for later use. (2) Add ZIF-based quantum dots, gallic acid and zirconium phosphate to water, and ultrasonically stir for 30-50 min to obtain an antibacterial composite solution. Add the titanium dioxide raw material obtained in (1) to the antibacterial composite solution, stir at 20-30℃ for 1.5-2.5 h, vacuum filter, and vacuum dry to obtain titanium dioxide-antibacterial composite particles. (3) Take tetraethyl orthosilicate water, add glacial acetic acid to adjust the pH to 4.5-5.0, and stir at 20-30℃ for 2.5-3.5h to form a silica layer raw material. Add titanium dioxide-antibacterial composite particles to the silica layer raw material and stir at 50-60℃ for 2.5-3.5h to obtain a mixed solution. Vacuum spray dry the mixed solution, calcine the dried powder at 800-900℃ for 0.5-1h, and pulverize it to 280-320 mesh to obtain a core-shell structure photocatalyst material.

[0017] The inlet temperature of the vacuum spray dryer in (3) above is 110-130℃, the outlet temperature is 55-65℃, and the feed rate is 45-55mL / min.

[0018] By employing the above technical solution, titanium dioxide is first formed through a stepwise coating process, providing a stable substrate for the subsequent adhesion of the antibacterial composite layer. Secondly, the antibacterial components are mixed with titanium dioxide, achieving a tight bond through intermolecular forces, reducing the risk of component detachment during use, and thus improving long-term antibacterial stability. Finally, the formation of the silica layer achieves uniform coating through controlled hydrolysis conditions, enhancing the overall structure's weather resistance, while pulverization ensures uniform particle size, reducing the impact of light scattering on optical properties. This approach ensures uniform dispersion of the antibacterial components for synergistic antibacterial effects, enhances long-term stability through structural reinforcement, and controls particle size and dispersibility to guarantee photocatalytic activity, ultimately improving the overall performance of the material.

[0019] In summary, this application includes at least one of the following beneficial technical effects: 1. The core-shell structured photocatalyst material of this application uses titanium dioxide as the core, coated with an antibacterial composite layer, and coated with a silica layer on the outside. The interaction between the core and shell structures can solve the problems of low antibacterial efficiency and insufficient long-term effect. The ZIF-based quantum dots, phenolic hydroxyl groups of gallic acid, and phosphate groups of zirconium phosphate in the antibacterial composite layer form hydrogen bonds with the silanol groups on the surface of silica, so that the silica layer is firmly coated, protecting the internal antibacterial components and ensuring long-term stability, enhancing structural stability, and prolonging the antibacterial effect.

[0020] 2. Through the shell-core structure of this application, titanium dioxide is first formed, providing a stable substrate for the subsequent adhesion of the antibacterial composite layer and avoiding the impact of particle agglomeration on the overall structural uniformity. By mixing the antibacterial components with titanium dioxide, a tight bond is achieved through intermolecular forces, thereby obtaining a long-lasting and stable antibacterial photocatalytic material. Detailed Implementation

[0021] Hydrochloric acid (37%), glacial acetic acid (99.5%): Sinopharm Chemical Reagent Co., Ltd.; Phosphoric acid (85%): Gaide Chemicals; Other raw materials can be obtained commercially.

[0022] Preparation Example 1 Preparation of ZIF-based quantum dots: The steps are as follows: 297.4g Zn(NO3)2·6H2O was dissolved in 1000g water to obtain solution A, and 164.2g 2-methylimidazole was dissolved in 1000g water to obtain solution B. Solution B was added dropwise to solution A at a rate of 10mL / min, stirred at 25℃ for 30min, centrifuged at 12000r / min for 20min, washed 3 times with anhydrous ethanol, and vacuum dried at 60℃ for 12h to obtain ZIF-8 nanoparticle precursor. Then, the temperature was increased to 300℃ at 5℃ / min and calcined for 2h to obtain ZIF-based quantum dots.

[0023] Preparation Example 2 Preparation of ZIF-based quantum dots: The steps are as follows: 277g Zn(NO3)2·6H2O was dissolved in 1000g water to obtain solution A, and 184.6g 2-methylimidazole was dissolved in 1000g water to obtain solution B. Solution B was added dropwise to solution A at a rate of 10mL / min, stirred at 25℃ for 30min, centrifuged at 12000r / min for 20min, washed 3 times with anhydrous ethanol, and vacuum dried at 60℃ for 12h to obtain ZIF-8 nanoparticle precursor. Then, the temperature was increased to 300℃ at 5℃ / min and calcined for 2h to obtain ZIF-based quantum dots.

[0024] Preparation Example 3 Preparation of ZIF-based quantum dots: The steps are as follows: 317.3g Zn(NO3)2·6H2O was dissolved in 1000g water to obtain solution A, and 144.3g 2-methylimidazole was dissolved in 1000g water to obtain solution B. Solution B was added dropwise to solution A at a rate of 10mL / min. The mixture was stirred at 25℃ for 30min, centrifuged at 12000r / min for 20min, washed three times with anhydrous ethanol, and vacuum dried at 60℃ for 12h to obtain ZIF-8 nanoparticle precursor. The temperature was then increased to 300℃ at 5℃ / min and calcined for 2h to obtain ZIF-based quantum dots.

[0025] Preparation Example 4 Preparation of ZIF-based nanoparticle precursor: The following steps were taken: 297.4 g Zn(NO3)2·6H2O was dissolved in 1000 g water to obtain solution A, and 164.2 g 2-methylimidazole was dissolved in 1000 g water to obtain solution B. Solution B was added dropwise to solution A at a rate of 10 mL / min, stirred at 25 °C for 30 min, centrifuged at 12000 r / min for 20 min, washed three times with anhydrous ethanol, and vacuum dried at 60 °C for 12 h to obtain ZIF-8 nanoparticle precursor.

[0026] Preparation Example 5 Preparation of zirconium phosphate: 178.7 g ZrOCl2·8H2O was dissolved in 800 g water, and the pH was adjusted to 1.2 with 37% hydrochloric acid to obtain solution C. 98.8 g phosphoric acid was dissolved in 200 g water to obtain solution D. Solution D was added dropwise to solution C at a rate of 5 mL / min. After stirring for 1 h, the solution was transferred to a reaction vessel and reacted at 180 °C for 24 h. The mixture was then centrifuged at 1000 r / min for 15 min, washed with water until the pH of the filtrate was 5.0, dried at 80 °C for 8 h, and calcined at 400 °C for 3 h to obtain zirconium phosphate.

[0027] Preparation Example 6 Preparation of zirconium phosphate: 170.8 g ZrOCl2·8H2O was dissolved in 800 g water, and the pH was adjusted to 1.2 with 37% hydrochloric acid to obtain solution C. 106.7 g phosphoric acid was dissolved in 200 g water to obtain solution D. Solution D was added dropwise to solution C at a rate of 5 mL / min. After stirring for 1 h, the solution was transferred to a reaction vessel and reacted at 180 °C for 24 h. The mixture was then centrifuged at 1000 r / min for 15 min, washed with water until the pH of the filtrate was 5.0, dried at 80 °C for 8 h, and calcined at 400 °C for 3 h to obtain zirconium phosphate.

[0028] Preparation Example 7 Preparation of zirconium phosphate: 195.9 g ZrOCl2·8H2O was dissolved in 800 g water, and the pH was adjusted to 1.2 with 37% hydrochloric acid to obtain solution C. 81.6 g phosphoric acid was dissolved in 200 g water to obtain solution D. Solution D was added dropwise to solution C at a rate of 5 mL / min. After stirring for 1 h, the solution was transferred to a reaction vessel and reacted at 180 °C for 24 h. The mixture was then centrifuged at 1000 r / min for 15 min, washed with water until the pH of the filtrate was 5.0, dried at 80 °C for 8 h, and calcined at 400 °C for 3 h to obtain zirconium phosphate.

[0029] Preparation Example 8 Preparation of zirconium phosphate: 178.7 g ZrOCl2·8H2O was dissolved in 800 g water, and the pH was adjusted to 1.2 with 37% hydrochloric acid to obtain solution C. 98.8 g phosphoric acid was dissolved in 200 g water to obtain solution D. Solution D was added dropwise to solution C at a rate of 5 mL / min. After stirring for 1 h, the solution was transferred to a reaction vessel and reacted at 180 °C for 24 h. The mixture was then centrifuged at 1000 r / min for 15 min, washed with water until the pH of the filtrate was 5.0, and dried at 80 °C for 8 h to obtain zirconium phosphate. Example 1

[0030] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 1, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide obtained in (1) to Add the antibacterial composite liquid to the mixture, stir at 25°C for 2 hours, vacuum filter at 0.09 MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 2

[0031] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 4g of ZIF-based quantum dots prepared in Preparation Example 1, 7g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 3

[0032] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 9g of ZIF-based quantum dots prepared in Preparation Example 1, 5g of gallic acid and 1g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 4

[0033] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 2, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 5

[0034] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 3, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 6

[0035] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 1, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 6, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 7

[0036] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 1, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 7, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material. Example 8

[0037] A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based quantum dots prepared in Preparation Example 1, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 8, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) Add the material to the antibacterial composite liquid, stir at 25°C for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material.

[0038] Comparative Example 1 A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 15g of ZIF-based quantum dots prepared in Preparation Example 1 and add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) to the antibacterial composite solution. Stir at 25℃ for 2 hours, vacuum filter at 0.09MPa, and vacuum dry at 50℃ for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25℃ for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55℃ for 3 hours to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120℃, an outlet temperature of 60℃, and a feed rate of 50mL / min. Calcine the dried powder at 800℃ for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material.

[0039] Comparative Example 2 A preparation process for a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 11g of ZIF-based quantum dots prepared in Preparation Example 1 and 4g of gallic acid, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) to the antibacterial composite solution. In the mixture, stir at 25°C for 2 hours, vacuum filter at 0.09 MPa, and vacuum dry at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and dry at 25°C for 3 hours to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55°C for 3 hours to obtain a mixture, vacuum spray dry the mixture at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. Calcinate the dried powder at 800°C for 1 hour and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material.

[0040] Comparative Example 3 A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 11g of ZIF-based quantum dots prepared in Preparation Example 1 and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide raw material obtained in (1) to In the antibacterial composite liquid, stir at 25℃ for 2h, vacuum filter at 0.09MPa, and vacuum dry at 50℃ for 1h to obtain titanium dioxide-antibacterial composite particles; (3) Take 36g of tetraethyl orthosilicate and 200g of water, add glacial acetic acid to adjust the pH to 5.0, and at 25℃ for 3h to form a silica layer raw material. Add the titanium dioxide-antibacterial composite particles to the silica layer raw material, stir at 55℃ for 3h to obtain a mixed liquid, vacuum spray dry the mixed liquid at an inlet temperature of 120℃, an outlet temperature of 60℃, and a feed rate of 50mL / min. Calcine the dried powder at 800℃ for 1h and pulverize it to 300 mesh to obtain a core-shell structure photocatalyst material.

[0041] Comparative Example 4 A process for preparing a core-shell structured photocatalyst material includes the following steps: (1) Dissolve 122.4g of tetrabutyl titanate in 1500g of ethanol, stir evenly, add 80.7g of hydrochloric acid and 800g of water, stir at 25°C for 12h, vacuum filter at 0.09MPa, and vacuum dry at 60°C for 1h to form titanium dioxide raw material for later use; (2) Take 7g of ZIF-based nanoparticle precursor prepared in Preparation Example 4, 4g of gallic acid and 4g of zirconium phosphate prepared in Preparation Example 5, add them to 500g of water, sonicate at 500W and 40kHz for 10min, stir at 300r / min for 30min to obtain an antibacterial composite solution, and add 45g of titanium dioxide obtained in (1) Titanium raw material was added to antibacterial composite liquid, stirred at 25°C for 2 hours, vacuum filtered at 0.09MPa, and vacuum dried at 50°C for 1 hour to obtain titanium dioxide-antibacterial composite particles; (3) 36g tetraethyl orthosilicate was added to 200g water, glacial acetic acid was added to adjust the pH to 5.0, and the mixture was dried at 25°C for 3 hours to form a silica layer raw material. Titanium dioxide-antibacterial composite particles were added to the silica layer raw material, stirred at 55°C for 3 hours to obtain a mixed liquid, and the mixed liquid was vacuum spray dried at an inlet temperature of 120°C, an outlet temperature of 60°C, and a feed rate of 50mL / min. The dried powder was calcined at 800°C for 1 hour and pulverized to 300 mesh to obtain a core-shell structure photocatalyst material.

[0042] The shell-core structured photocatalyst materials prepared in the examples and comparative examples were tested for antibacterial properties according to WS / T 650-2019 "Evaluation Methods for Antibacterial and Bacteriostatic Effects". The bacterial strains were Escherichia coli (8099) and Staphylococcus aureus (ATCC 6538), and the bacterial concentration was 1×10⁻⁶. 5 CFU / mL; the antibacterial rate was retested after 1000h xenon lamp aging, and the test results are shown in Table 1: Table 1 Performance Test Results

[0043] Experimental data show that the core-shell structure photocatalyst materials prepared in Examples 1-8 of this application exhibit significantly improved antibacterial performance compared to Comparative Examples 1-4. Combining Examples 1, 1-3, and Comparative Examples 1-2, it is evident that ZIF-based quantum dots not only ensure high dispersion of the titanium dioxide core layer, thus laying the structural foundation for the material's photocatalytic and contact antibacterial properties, but the introduction of gallic acid further enhances the contact antibacterial effect. The layered structure of zirconium phosphate can physically capture bacteria, and its surface phosphate groups adsorb bacteria through electrostatic interactions, improving the contact efficiency between bacteria and antibacterial active sites. The interaction of these three factors enhances the antibacterial effect. Furthermore, after 2000 hours of xenon lamp aging, the core-shell structure photocatalyst material prepared in Example 1 of this application showed an antibacterial rate of 88.9% against Escherichia coli and 86.7% against Staphylococcus aureus. After 2000 hours of xenon lamp aging, the core-shell structure photocatalyst material prepared in Example 2 of this application showed an antibacterial rate of 72.5% against Staphylococcus aureus.

[0044] As can be seen from Examples 1, 4-8, and Comparative Examples 3-4, a coordination reaction forms a well-structured ZIF-8 nanoparticle precursor. Calcination modification of this precursor not only maintains its high dispersibility and activity at the quantum dot scale but also enhances its antibacterial stability and lifespan through the stabilizing effect of the framework. The layered mesoporous structure of zirconium phosphate has a mesopore size that can be adapted to the size of Staphylococcus aureus cells, enabling efficient capture through physical sieving. Furthermore, its negatively charged phosphate groups can form adsorption properties, adsorbing the strongly negatively charged surface of Escherichia coli and achieving localized enrichment of Escherichia coli.

[0045] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A core-shell structured photocatalytic material, characterized in that: The core-shell structure photocatalyst material includes titanium dioxide, an antibacterial composite layer and a silicon dioxide layer sequentially coated thereon, and the raw materials of the antibacterial composite layer include ZIF-based quantum dots, gallic acid and zirconium phosphate; the mass ratio of ZIF-based quantum dots, gallic acid and zirconium phosphate is (5-8):(3-5):(2-4).

2. The core-shell structured photocatalyst material according to claim 1, characterized in that: The preparation method of the ZIF-based quantum dots includes the following steps: dissolving Zn(NO3)2·6H2O in water to obtain solution A, dissolving 2-methylimidazole in water to obtain solution B, adding solution B dropwise to solution A, stirring at 20-30℃ for 25-35 min, centrifuging and washing, vacuum drying at 65-75℃ for 10-14 h to obtain ZIF-8 nanoparticle precursor, and then calcining at 280-320℃ for 1.5-2.5 h to obtain ZIF-based quantum dots.

3. The core-shell structured photocatalyst material according to claim 2, characterized in that: The mass ratio of Zn(NO3)2·6H2O to 2-methylimidazole is (1.7-1.9):

1.

4. The core-shell structured photocatalyst material according to claim 1, characterized in that: The method for preparing zirconium phosphate includes: dissolving ZrOCl2·8H2O in water, adjusting the pH value to 0.8-1.2 with hydrochloric acid to obtain solution C, dissolving phosphoric acid in water to obtain solution D, adding solution D dropwise to solution C, stirring for 0.8-1.2 h, transferring to a reaction vessel, reacting at 170-190℃ for 22-26 h, centrifuging, washing, drying, and then calcining at 380-420℃ for 2.5-3.5 h.

5. The core-shell structured photocatalyst material according to claim 4, characterized in that: The mass ratio of ZrOCl2·8H2O to phosphoric acid is (1.8-2.2):

1.

6. The preparation process of the core-shell structured photocatalyst material according to any one of claims 1-5, characterized in that: Includes the following steps: (1) Dissolve tetrabutyl titanate in ethanol, stir evenly, add hydrochloric acid and water, stir at 20-30℃ for 10-14h to form titanium dioxide for later use. (2) Add ZIF-based quantum dots, gallic acid and zirconium phosphate to water, and ultrasonically stir for 30-50 min to obtain an antibacterial composite solution. Add the titanium dioxide obtained in (1) to the antibacterial composite solution, stir at 20-30℃ for 1.5-2.5 h, vacuum filter, and vacuum dry to obtain titanium dioxide-antibacterial composite particles. (3) Take tetraethyl orthosilicate water, add glacial acetic acid to adjust the pH to 4.5-5.0, and stir at 20-30℃ for 2.5-3.5h to form a silica layer raw material. Add titanium dioxide-antibacterial composite particles to the silica layer raw material and stir at 50-60℃ for 2.5-3.5h to obtain a mixed solution. Vacuum spray dry the mixed solution, calcine the dried powder at 800-900℃ for 0.5-1h, and pulverize it to 280-320 mesh to obtain a core-shell structure photocatalyst material.

7. The preparation process of the core-shell structured photocatalyst material according to claim 6, characterized in that: The inlet temperature of the vacuum spray dryer in (3) is 110-130℃, the outlet temperature is 55-65℃, and the feed rate is 45-55mL / min.

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