Titanium dioxide photocatalytic coating, method of making and product

Abstract

This invention relates to a titanium dioxide photocatalytic coating, its preparation method, and the product thereof. The preparation method includes the following steps: heating ethanol to 70℃-80℃ and generating reflux, adding glyceryl tristearate, mixing under reflux until completely dissolved, then adding water and mixing to obtain an oil-in-water emulsion; mixing an organic titanate, acetic acid, and ethanol to obtain a mixed solution; adding the mixed solution in batches to the oil-in-water emulsion and heating and stirring at 70℃-80℃ to obtain a titanium dioxide microsphere dispersion; spraying the titanium dioxide microsphere dispersion onto a carrier at 70℃-80℃ to obtain a titanium dioxide photocatalytic coating. This preparation method not only maintains a large reactive surface area in the titanium dioxide photocatalytic coating but also improves the fixation strength of titanium dioxide on the carrier, thereby obtaining a high-firmness, high-catalytic-activity titanium dioxide photocatalytic coating.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic materials technology, and in particular to a titanium dioxide photocatalytic coating, its preparation method, and the product thereof. Background Technology

[0002] Titanium dioxide (TiO2) is a photocatalytic nanomaterial with high photocatalytic activity. Titanium dioxide can promote oxidative decomposition reactions with the help of light; it is a substance that does not change itself under light irradiation but can promote chemical reactions. Under sunlight or indoor fluorescent light irradiation, titanium dioxide photocatalytic nanomaterials can produce antibacterial, deodorizing, oil-decomposing, mildew- and algae-preventing, and air-purifying effects, and are therefore widely studied and applied in the degradation of organic pollutants.

[0003] However, since titanium dioxide photocatalytic nanomaterials are in powder form, they typically need to be loaded onto a support in practical applications. Traditional techniques usually involve mixing titanium dioxide photocatalytic nanoparticles with a binder to form a colloid, which is then coated onto the surface of the support, creating a photocatalytic coating. While this colloidal film-forming method enhances the fixation of the titanium dioxide photocatalytic nanoparticles on the support, it also leads to the nanoparticles being sealed within the film by the binder. This results in the loss of the nanoparticles' large specific surface area, ultimately reducing the overall photocatalytic activity of the coating. Summary of the Invention

[0004] Therefore, it is necessary to provide a titanium dioxide photocatalytic coating, its preparation method, and the product to address the above problems. The preparation method not only enables the titanium dioxide photocatalytic coating to maintain a large reactive surface area, but also improves the fixation strength of titanium dioxide on the carrier, thereby obtaining a titanium dioxide photocatalytic coating with high stability and high catalytic activity.

[0005] A method for preparing a titanium dioxide photocatalytic coating includes the following steps:

[0006] Ethanol was heated to 70℃-80℃ and refluxed, then glyceryl tristearate was added and mixed under reflux until completely dissolved. Water was then added and mixed to obtain an oil-in-water emulsion.

[0007] Organic titanate, acetic acid and ethanol are mixed to obtain a mixed solution;

[0008] The mixed solution was added to the oil-in-water emulsion in batches and heated and mixed at 70℃-80℃ to obtain a titanium dioxide microsphere dispersion.

[0009] The titanium dioxide microsphere dispersion was sprayed onto a carrier at 70℃-80℃ to obtain a titanium dioxide photocatalytic coating.

[0010] In one embodiment, 0.5 g to 6 g of the tristearate is added to every 100 mL of the ethanol.

[0011] In one embodiment, the water-in-oil emulsion has a mass ratio of water to tristearate glyceryl ester of 5:3 to 30:1.

[0012] In one embodiment, the volume ratio of the organic titanate, the acetic acid and the ethanol in the mixed solution is (4-7):(3-7):(10-20).

[0013] In one embodiment, the organotitanate is selected from at least one of tetrabutyl titanate, tetraethyl titanate, and tetraisopropyl titanate.

[0014] In one embodiment, in the step of spraying the titanium dioxide microsphere dispersion onto a carrier at 70°C-80°C, the distance between the spraying device and the carrier is 20cm-30cm.

[0015] And / or, the spraying rate of the titanium dioxide microsphere dispersion is 0.3 mL / h-0.7 mL / h.

[0016] In one embodiment, the mixing time of the tristearate and the ethanol is 0.5h-3h;

[0017] And / or, the mixing time for adding water is 0.5h-2h;

[0018] And / or, the mixing time of the organotitanate with the acetic acid and the ethanol is 0.5h-2h;

[0019] And / or, the heating and mixing time is 1h-3h.

[0020] A titanium dioxide photocatalytic coating prepared by the method described above includes a tristearate layer and titanium dioxide microspheres exposed on the surface of the tristearate layer.

[0021] In one embodiment, the titanium dioxide microspheres are a ring structure with a central depression.

[0022] A product includes a carrier and a titanium dioxide photocatalytic coating as described above loaded on the surface of the carrier.

[0023] The preparation method described in this invention uses a specific tristearate as a binder. Taking advantage of the soluble nature of tristearate in hot ethanol at high temperatures, hot ethanol is used as the solute dispersion medium, allowing tristearate and water to form an oil-in-water emulsion. Furthermore, when a mixed solution containing organic titanates is mixed with the oil-in-water emulsion, the organic titanates undergo a hydrolysis reaction with the water shell in the oil-in-water emulsion structure to generate titanium dioxide, which coats the surface of the tristearate droplets, forming a titanium dioxide microsphere structure with titanium dioxide as the shell and tristearate as the core. Therefore, when the titanium dioxide microsphere dispersion is sprayed onto a carrier at 70℃-80℃, the titanium dioxide microsphere structure collapses, and the internal tristearate flows out. This not only firmly fixes the titanium dioxide microspheres to the carrier surface but also prevents the titanium dioxide microspheres from being covered by tristearate, allowing the titanium dioxide microspheres to maintain a large reactive surface area.

[0024] Therefore, the preparation method described in this invention constructs titanium dioxide microspheres with a core-shell structure during the preparation process, enabling each titanium dioxide microsphere to have its own binder, thus achieving precise fixation of the titanium dioxide microspheres. This results in a titanium dioxide photocatalytic coating with high adhesion and high catalytic activity. Furthermore, this preparation method is simple, the conditions are easy to control, and it can achieve large-scale industrial production, demonstrating significant application potential. Attached Figure Description

[0025] Figure 1 The images shown are scanning electron microscope (SEM) images of the titanium dioxide photocatalytic coating prepared in Example 1 of the present invention under different magnification conditions. Among them, a is a scanning electron microscope image of the titanium dioxide photocatalytic coating under 500x magnification and b is a scanning electron microscope image of the titanium dioxide photocatalytic coating under 2500x magnification.

[0026] Figure 2 This is a scanning electron microscope image of titanium dioxide microspheres in the titanium dioxide photocatalytic coating prepared in Example 1 of the present invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0028] Unless otherwise defined, 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 pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0029] This invention provides a method for preparing a titanium dioxide photocatalytic coating, comprising the following steps:

[0030] S1. Ethanol is heated to 70℃-80℃ and refluxed, then glyceryl tristearate is added and mixed under reflux until completely dissolved. Water is then added and mixed to obtain an oil-in-water emulsion.

[0031] S2, mix organic titanate, acetic acid and ethanol to obtain a mixed solution;

[0032] S3, the mixed solution is added to the oil-in-water emulsion in batches and heated and mixed at 70℃-80℃ to obtain a titanium dioxide microsphere dispersion;

[0033] S4, the titanium dioxide microsphere dispersion is sprayed onto a carrier at 70℃-80℃ to obtain a titanium dioxide photocatalytic coating.

[0034] In steps S1 to S3, a specific tristearate is first used as a binder. Taking advantage of the soluble nature of tristearate in hot ethanol, hot ethanol is used as the solute dispersion medium, allowing tristearate and water to form an oil-in-water emulsion. Then, when the mixed solution containing organic titanate is mixed with the oil-in-water emulsion, the organic titanate undergoes a hydrolysis reaction with the water shell in the oil-in-water emulsion structure to generate titanium dioxide, which coats the surface of the tristearate droplets, forming a titanium dioxide microsphere structure with titanium dioxide as the shell and tristearate as the core.

[0035] Considering the volatile nature of ethanol, under heating conditions of 70℃-80℃, ethanol needs to be replenished by reflux to avoid ethanol evaporation loss. Preferably, the ethanol is selected from anhydrous ethanol.

[0036] Preferably, the amount of tristearate added to each 100 mL of ethanol is 0.5 g to 6 g, which is beneficial for better dissolution of tristearate in high-temperature ethanol.

[0037] More preferably, the amount of tristearate added to each 100 mL of the ethanol is 1 g to 3 g.

[0038] In one embodiment, the mixing time of the tristearate and the ethanol is 0.5h-3h, which is more conducive to the dissolution of the tristearate.

[0039] Preferably, in the oil-in-water emulsion, the mass ratio of water to tristearate is 5:3-30:1, which is beneficial for forming an oil-in-water structure.

[0040] More preferably, the mass ratio of water to tristearate is 10:1 to 20:1.

[0041] In one embodiment, the mixing time with added water is 0.5h-2h, which can make the droplets more evenly dispersed and more conducive to the formation of a large number of uniform oil-in-water structures.

[0042] By adding acetic acid, the pH of the reaction system can be adjusted, thereby controlling the hydrolysis rate, inhibiting or slowing down the formation of titanium dioxide, which is conducive to the formation of a stable titanium dioxide microsphere dispersion and avoids problems such as demulsification of titanium dioxide microspheres caused by excessively fast titanium dioxide reaction rate.

[0043] Preferably, in the mixed solution, the volume ratio of the organic titanate, the acetic acid and the ethanol is (4-7):(3-7):(10-20).

[0044] Specifically, the organotitanate is selected from at least one of tetrabutyl titanate, tetraethyl titanate, and tetraisopropyl titanate, and is more preferably tetrabutyl titanate.

[0045] The water is preferably ultrapure water.

[0046] In one embodiment, the mixing time of the organic titanate with the acetic acid and the ethanol is 0.5h-2h.

[0047] In the step of adding the oil-in-water emulsion to the mixed solution in batches, the method of batch addition includes, but is not limited to, dropwise addition, etc. The present invention does not limit this, and those skilled in the art can choose according to actual preparation needs.

[0048] Furthermore, the preferred method of adding the ingredients in batches is dripping.

[0049] It should be noted that the present invention does not limit the method and rate of drop addition, and those skilled in the art can adjust them according to actual preparation needs.

[0050] Heating and mixing can make the mixed solution disperse evenly in the oil-in-water emulsion, which is beneficial for the formation of more uniform titanium dioxide microspheres.

[0051] Preferably, the heating and mixing time is 1-3 hours, which is beneficial for the complete growth of titanium dioxide and the formation of a more stable titanium dioxide microsphere dispersion.

[0052] In step S4, when the titanium dioxide microsphere dispersion is sprayed onto a carrier at 70℃-80℃, the titanium dioxide microspheres vibrate fully under the spraying action and are subjected to the inertial force of the tristearate glycerol inside the titanium dioxide microspheres. This results in a large velocity gradient shear force when the titanium dioxide microspheres come into contact with the carrier, making it easier to disrupt the stability of the titanium dioxide microsphere structure and causing the titanium dioxide microsphere structure to collapse. Furthermore, contact with the carrier at 70℃-80℃ is more conducive to the outflow of tristearate glycerol inside the titanium dioxide microspheres. This not only firmly fixes the titanium dioxide microspheres on the carrier surface but also prevents the titanium dioxide microspheres from being covered by tristearate glycerol, allowing the titanium dioxide microspheres to maintain a large reactive surface area, thereby significantly improving the photocatalytic performance of the titanium dioxide photocatalytic coating.

[0053] In one embodiment, in the step of spraying the titanium dioxide microsphere dispersion onto a carrier at 70°C-80°C, the distance between the spraying device and the carrier is 20cm-30cm; and / or, the spraying rate of the titanium dioxide microsphere dispersion is 0.3mL / h-0.7mL / h.

[0054] The spraying method includes, but is not limited to, high-voltage electrostatic spraying, etc. The present invention does not limit this method, and those skilled in the art can choose according to actual preparation needs.

[0055] Furthermore, the spraying method is preferably high-pressure electrostatic spraying.

[0056] Therefore, the preparation method of the present invention constructs titanium dioxide microspheres with a core-shell structure during the preparation process, so that each titanium dioxide microsphere has its own adhesive, thereby achieving precise fixation of titanium dioxide microspheres. Moreover, the preparation method is simple, the conditions are easy to control, and it can realize mass industrial production, and has great application potential.

[0057] A titanium dioxide photocatalytic coating prepared by the method described above includes a tristearate layer and titanium dioxide microspheres exposed on the surface of the tristearate layer.

[0058] Preferably, the titanium dioxide microspheres have a ring-shaped structure with a central depression.

[0059] It should be noted that the titanium dioxide microspheres can be partially exposed on the surface of the tristearate layer, meaning the titanium dioxide microspheres are partially embedded in the tristearate layer. Alternatively, the titanium dioxide microspheres can be completely exposed on the surface of the tristearate layer, meaning the bottom portion of the titanium dioxide microspheres is bonded to the tristearate layer. This invention does not limit the specific type of microspheres. The thickness of the titanium dioxide photocatalytic coating is not limited in this invention; those skilled in the art can adjust it according to actual application requirements.

[0060] The present invention also provides a product comprising a carrier and a titanium dioxide photocatalytic coating as described above loaded on the surface of the carrier.

[0061] This invention does not limit the choice of carrier. Different carriers can be selected to load the titanium dioxide photocatalytic coating according to the application requirements of different products.

[0062] This product can be used for antibacterial, deodorizing, oil decomposition, mildew and algae prevention, and air purification, and has a wide range of applications.

[0063] The following specific examples will further illustrate the titanium dioxide photocatalytic coating, its preparation method, and the product.

[0064] Example 1

[0065] In a reflux apparatus, 50 mL of anhydrous ethanol was heated to 70 °C to induce reflux. Subsequently, 0.5 g of tristearate was added to the hot anhydrous ethanol, and the mixture was stirred under reflux for 0.5 h to completely dissolve the tristearate. Then, 5 mL of ultrapure water was added, and stirring was continued for another 0.5 h to obtain an oil-in-water emulsion.

[0066] Add 20 mL of tetrabutyl titanate and 15 mL of acetic acid to 50 mL of anhydrous ethanol, and stir for 0.5 h to mix them evenly to obtain a mixed solution.

[0067] While maintaining a heating temperature of 70°C, the mixed solution was added dropwise to the oil-in-water emulsion under high-speed stirring. After the addition was completed, stirring was continued for 1 hour, and then the mixture was cooled to room temperature to obtain a titanium dioxide microsphere dispersion.

[0068] The titanium dioxide microsphere dispersion was placed in a syringe, and the stainless steel needle at one end of the syringe was connected to a 23kV positive high voltage power supply. The distance between the stainless steel needle and the carrier was adjusted to approximately 20cm, and the carrier was heated to 70℃. The ambient temperature was adjusted to 30±2℃ and the humidity to 30±5%, and the injection rate was set to 0.5mL / h. High-voltage electrostatic field spraying was then performed to obtain the titanium dioxide photocatalytic coating.

[0069] The surface morphology of the prepared titanium dioxide photocatalytic coating was observed using scanning electron microscopy at different magnifications. Figure 1 As shown in a and b, a large number of titanium dioxide microspheres are exposed on the surface of the titanium dioxide photocatalytic coating. Furthermore, according to b under the condition of higher magnification, it can be seen that the titanium dioxide microspheres are relatively uniform in size, indicating that the titanium dioxide microspheres are not covered by tristearate.

[0070] Further, the surface morphology of the titanium dioxide microspheres in the prepared titanium dioxide photocatalytic coating was observed using scanning electron microscopy at a magnification of approximately 70,000 times. Figure 2 As shown, the titanium dioxide microspheres have a ring structure with a central depression and a particle size of about 300 nm.

[0071] Example 2

[0072] In a reflux apparatus, 60 mL of anhydrous ethanol was heated to 75 °C to induce reflux. Subsequently, 1 g of tristearate was added to the hot anhydrous ethanol, and the mixture was stirred under reflux for 1.5 h to completely dissolve the tristearate. Then, 5 mL of ultrapure water was added, and stirring was continued for another 0.5 h to obtain an oil-in-water emulsion.

[0073] Add 25 mL of tetrabutyl titanate and 20 mL of acetic acid to 65 mL of anhydrous ethanol, and stir for 0.5 h to mix them evenly to obtain a mixed solution.

[0074] While maintaining a heating temperature of 75°C, the mixed solution was added dropwise to the oil-in-water emulsion under high-speed stirring. After the addition was completed, stirring was continued for 1 hour, and then the mixture was cooled to room temperature to obtain a titanium dioxide microsphere dispersion.

[0075] The titanium dioxide microsphere dispersion was placed in a syringe, and the stainless steel needle at one end of the syringe was connected to a 23kV positive high voltage power supply. The distance between the stainless steel needle and the carrier was adjusted to approximately 20cm, and the carrier was heated to 70℃. The ambient temperature was adjusted to 30±2℃ and the humidity to 30±5%, and the injection rate was set to 0.5mL / h. High-voltage electrostatic field spraying was then performed to obtain the titanium dioxide photocatalytic coating.

[0076] Example 3

[0077] In a reflux apparatus, 90 mL of anhydrous ethanol was heated to 80 °C to induce reflux. Subsequently, 3 g of tristearate was added to the hot anhydrous ethanol, and the mixture was stirred under reflux for 3 h to completely dissolve the tristearate. Then, 10 mL of ultrapure water was added, and stirring was continued for 1 h to obtain an oil-in-water emulsion.

[0078] Add 30 mL of tetrabutyl titanate and 25 mL of acetic acid to 85 mL of anhydrous ethanol, and stir for 1 h to mix them evenly to obtain a mixed solution.

[0079] While maintaining a heating temperature of 80°C, the mixed solution was added dropwise to the oil-in-water emulsion under high-speed stirring. After the addition was completed, stirring was continued for 1 hour, and then the mixture was cooled to room temperature to obtain a titanium dioxide microsphere dispersion.

[0080] The titanium dioxide microsphere dispersion was placed in a syringe, and the stainless steel needle at one end of the syringe was connected to a 23kV positive high voltage power supply. The distance between the stainless steel needle and the carrier was adjusted to approximately 20cm, and the carrier was heated to 70℃. The ambient temperature was adjusted to 30±2℃ and the humidity to 30±5%, and the injection rate was set to 0.5mL / h. High-voltage electrostatic field spraying was then performed to obtain the titanium dioxide photocatalytic coating.

[0081] Example 4

[0082] In a reflux apparatus, 50 mL of anhydrous ethanol was heated to 75 °C to induce reflux. Subsequently, 3 g of tristearate was added to the hot anhydrous ethanol, and the mixture was stirred under reflux for 2 h to completely dissolve the tristearate. Then, 5 mL of ultrapure water was added, and stirring was continued for 0.5 h to obtain an oil-in-water emulsion.

[0083] Add 35 mL of tetrabutyl titanate and 35 mL of acetic acid to 100 mL of anhydrous ethanol and stir for 2 hours to mix them evenly, thus obtaining a mixed solution.

[0084] While maintaining a heating temperature of 75°C, the mixed solution was added dropwise to the oil-in-water emulsion under high-speed stirring. After the addition was completed, stirring was continued for 2 hours, and then the mixture was cooled to room temperature to obtain a titanium dioxide microsphere dispersion.

[0085] A titanium dioxide microsphere dispersion was placed in a syringe, and the stainless steel needle at one end of the syringe was connected to a 23kV positive high-voltage power supply. The distance between the stainless steel needle and the carrier was adjusted to approximately 30cm, and the carrier was heated to 70℃. The ambient temperature was adjusted to 30±2℃ and the humidity to 30±5%, and the injection rate was set to 0.5mL / h. High-voltage electrostatic spraying was then performed to obtain a titanium dioxide photocatalytic coating.

[0086] Example 5

[0087] In a reflux apparatus, 100 mL of anhydrous ethanol was heated to 75 °C to induce reflux. Subsequently, 0.5 g of tristearate was added to the hot anhydrous ethanol, and the mixture was stirred under reflux for 1 h to completely dissolve the tristearate. Then, 15 mL of ultrapure water was added, and stirring was continued for 2 h to obtain an oil-in-water emulsion.

[0088] Add 20 mL of tetraethyl titanate and 20 mL of acetic acid to 70 mL of anhydrous ethanol, and stir for 1 hour to mix them evenly to obtain a mixed solution.

[0089] While maintaining a heating temperature of 75°C, the mixed solution was added dropwise to the oil-in-water emulsion under high-speed stirring. After the addition was completed, stirring was continued for 1 hour, and then the mixture was cooled to room temperature to obtain a titanium dioxide microsphere dispersion.

[0090] The titanium dioxide microsphere dispersion was placed in a syringe, and the stainless steel needle at one end of the syringe was connected to a 23kV positive high voltage power supply. The distance between the stainless steel needle and the carrier was adjusted to approximately 20cm, and the carrier was heated to 70℃. The ambient temperature was adjusted to 30±2℃ and the humidity to 30±5%, and the injection rate was set to 0.5mL / h. High-voltage electrostatic field spraying was then performed to obtain the titanium dioxide photocatalytic coating.

[0091] Comparative Example 1

[0092] Add 20 mL of tetrabutyl titanate and 15 mL of acetic acid to 50 mL of anhydrous ethanol, and stir for 0.5 h to mix them evenly to obtain a mixed solution.

[0093] The mixed solution was added dropwise to water under high-speed stirring. After the addition was completed, stirring was continued for 1 hour. After filtration and washing, titanium dioxide powder was obtained.

[0094] Under heating conditions, titanium dioxide powder and glyceryl tristearate are mixed evenly to obtain a colloid solution, which is then coated onto the surface of a carrier to obtain a titanium dioxide photocatalytic coating.

[0095] Comparative Example 2

[0096] The difference between Comparative Example 2 and Example 1 is that methyl methacrylate is used instead of glyceryl tristearate.

[0097] Comparative Example 3

[0098] The difference between Comparative Example 3 and Example 1 is that acetic acid was not added when preparing the mixed solution.

[0099] Comparative Example 4

[0100] The difference between Comparative Example 4 and Example 1 is that the mixed solution was directly mixed and stirred with the oil-in-water emulsion instead of being added dropwise.

[0101] Comparative Example 5

[0102] The difference between Comparative Example 5 and Example 1 is that the carrier was not heated.

[0103] Performance tests were conducted on Examples 1-5 and Comparative Examples 1-5 using the following method: an abrasion test was performed using weights / sandpaper, and the photocatalytic activity was measured after 280 sandpaper abrasion cycles. The photocatalytic activity was characterized using the classic Rhodamine B solution decolorization reaction, where the initial concentration of the Rhodamine B solution was 5 × 10⁻⁶. -5 The concentration was mol / L. After 10 minutes of illumination, a higher fading rate indicated better photocatalytic activity. The test results are shown in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, the titanium dioxide photocatalytic coatings prepared in Examples 1-5 have good initial photocatalytic activity, and can still maintain about 90% of the initial photocatalytic activity after 280 sandpaper abrasion cycles.

[0107] Comparative Example 1 uses the traditional direct mixing method, which causes the titanium dioxide photocatalytic nanoparticles to be sealed in the membrane by the binder, resulting in the loss of the large specific surface area characteristic of the titanium dioxide photocatalytic nanoparticles and thus poor photocatalytic performance.

[0108] Comparative Example 2 used methyl methacrylate as a binder. Since methyl methacrylate can be dissolved in both hot ethanol and hot water, after mixing methyl methacrylate with ethanol and ultrapure water in sequence under heating conditions, an oil-in-water emulsion failed to be formed, and thus the titanium dioxide microsphere structure could not be obtained. As a result, the titanium dioxide in the titanium dioxide photocatalytic coating was covered by methyl methacrylate, resulting in poor photocatalytic performance.

[0109] In Comparative Examples 3 and 4, the titanium dioxide reaction rate was too fast, which caused the titanium dioxide microspheres to demulsify and failed to prepare a titanium dioxide microsphere dispersion. As a result, the titanium dioxide in the titanium dioxide photocatalytic coating was covered by tristearate glycerol, and therefore the photocatalytic performance was poor.

[0110] In Comparative Example 5, because the support was not heated to 70℃-80℃, the titanium dioxide microspheres ruptured, and the internal tristearate glycerol had a high viscosity and failed to flow out from the ruptured titanium dioxide shell. This resulted in poor fixation of the titanium dioxide on the support, making it very easy to detach from the support surface during the catalytic reaction. Therefore, the photocatalytic performance decreased sharply as the reaction time increased.

[0111] Therefore, the above examples and comparative examples demonstrate that the preparation method provided by the present invention can not only maintain a large reactive surface area of ​​the titanium dioxide photocatalytic coating, but also improve the fixation strength of titanium dioxide on the carrier, thereby obtaining a titanium dioxide photocatalytic coating with high strength and high catalytic activity.

[0112] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a titanium dioxide photocatalytic coating, characterized in that, Includes the following steps: Ethanol is heated to 70℃-80℃ and refluxed, then glyceryl tristearate is added and mixed under reflux until completely dissolved. Water is then added and mixed to obtain an oil-in-water emulsion. The amount of glyceryl tristearate added to each 100mL of ethanol is 0.5g-6g, and the mass ratio of water to glyceryl tristearate in the oil-in-water emulsion is 5:3-30:

1. Organic titanate, acetic acid, and ethanol are mixed to obtain a mixed solution; The mixed solution was added to the oil-in-water emulsion in batches and heated and mixed at 70°C-80°C, then cooled to room temperature to obtain a titanium dioxide microsphere dispersion. The heating and mixing time was 1h-3h, and the batch addition was done by dropwise addition. The titanium dioxide microsphere dispersion was sprayed onto a carrier at 70℃-80℃ to obtain a titanium dioxide photocatalytic coating.

2. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, The amount of tristearate added to each 100 mL of the ethanol is 1 g to 3 g.

3. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, In the oil-in-water emulsion, the mass ratio of water to tristearate is 10:1-20:

1.

4. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, In the mixed solution, the volume ratio of the organic titanate, the acetic acid and the ethanol is (4-7):(3-7):(10-20).

5. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, The organic titanate is selected from at least one of tetrabutyl titanate, tetraethyl titanate, and tetraisopropyl titanate.

6. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, In the step of spraying the titanium dioxide microsphere dispersion onto a carrier at 70℃-80℃, the distance between the spraying device and the carrier is 20cm-30cm. And / or, the spraying rate of the titanium dioxide microsphere dispersion is 0.3 mL / h-0.7 mL / h.

7. The method for preparing the titanium dioxide photocatalytic coating according to claim 1, characterized in that, The mixing time of the tristearate and the ethanol is 0.5h-3h; And / or, the mixing time for adding water is 0.5h-2h; And / or, the mixing time of the organic titanate with the acetic acid and the ethanol is 0.5h-2h.

8. A product characterized in that, Includes a carrier, and a titanium dioxide photocatalytic coating prepared by the method of any one of claims 1-7 loaded on the surface of the carrier.

9. The product according to claim 8, characterized in that, The titanium dioxide photocatalytic coating includes a tristearate layer and titanium dioxide microspheres exposed on the surface of the tristearate layer.

10. The product according to claim 9, characterized in that, The titanium dioxide microspheres have a ring-shaped structure with a central depression.

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