A photocatalytic coating, a preparation method and application thereof

Abstract

The application discloses a kind of photocatalytic coating and its preparation method and application.The photocatalytic coating of the application includes the following weight percentage components: light-transmitting resin: 0.5%~2%;carbon quantum dots modified nano-titanium dioxide: 0.5%~2%;water: 96%~99%.The preparation method of the photocatalytic coating of the application includes the following steps: light-transmitting resin is dissolved in water, then carbon quantum dots modified nano-titanium dioxide is added and mixed evenly, and the photocatalytic coating is obtained.The photocatalytic coating of the application coated on the inner surface of lamp lens can form a coating layer with photocatalytic degradation effect, which can degrade the oil stains attached to the inner surface of the lamp lens through photocatalytic reaction, can keep the lamp lens with high light transmittance, and finally can effectively prolong the service life of the lamp.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocatalysis, in particular to a photocatalytic coating, a preparation method and application thereof. BACKGROUND

[0002] The lens of a lamp is an important component of the lamp, and its light transmission performance will directly affect the lighting effect of the lamp. During long-term use, the inner surface of the lens of the lamp is prone to adhere to pollutants such as oil stains and dust, thereby causing the light transmittance to decrease, and ultimately directly affecting the lighting effect of the lamp. Traditional lens cleaning methods of the lamp include manual wiping and chemical cleaning, which are not only cumbersome to operate, but also may damage the lens surface and shorten the service life of the lamp.

[0003] Therefore, it is of great significance to develop a method for solving the pollution problem of the inner surface of the lens of the lamp, which has better effect and is simpler to operate. SUMMARY

[0004] The present application relates to the field of photocatalysis, in particular to a photocatalytic coating, a preparation method and application thereof.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A photocatalytic coating comprises the following components by weight percentage:

[0007] Light-transmitting resin: 0.5% to 2%;

[0008] Carbon quantum dot modified nano-titanium dioxide: 0.5% to 2%;

[0009] Water: 96% to 99%.

[0010] Preferably, the light-transmitting resin is at least one of polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyurethane (PU).

[0011] Preferably, the number average molecular weight of the polyvinyl alcohol is 10,000 to 100,000.

[0012] Preferably, the number average molecular weight of the polymethyl methacrylate is 50,000 to 500,000.

[0013] Preferably, the number average molecular weight of the polycarbonate is 20,000 to 200,000.

[0014] Preferably, the number average molecular weight of the polyethylene is 20,000 to 200,000.

[0015] Preferably, the number average molecular weight of the polypropylene is 30,000 to 300,000.

[0016] Preferably, the number average molecular weight of the polystyrene is 30000-300000.

[0017] Preferably, the number average molecular weight of the polyurethane is 50000-500000.

[0018] Preferably, the weight ratio of the nanometer titanium dioxide to the carbon quantum dots in the carbon quantum dot modified nanometer titanium dioxide is 1:0.05-0.5.

[0019] Preferably, the particle size of the nanometer titanium dioxide in the carbon quantum dot modified nanometer titanium dioxide is 20nm-100nm.

[0020] Preferably, the particle size of the carbon quantum dots in the carbon quantum dot modified nanometer titanium dioxide is ≤10nm.

[0021] Preferably, the carbon quantum dot modified nanometer titanium dioxide is made by a preparation method comprising the following steps:

[0022] 1) immersing secondary collagen fibers in an alkali solution for immersion treatment to obtain a secondary collagen fiber extract;

[0023] 2) heating the secondary collagen fiber extract for hydrothermal reaction, and then separating the product to obtain carbon quantum dots;

[0024] 3) adding nanometer titanium dioxide and carbon quantum dots into a solvent, mixing thoroughly, and then drying to obtain carbon quantum dot modified nanometer titanium dioxide.

[0025] Preferably, the secondary collagen fibers in step 1) are recycled collagen fibers made from waste leather by mechanical or chemical method. The principle of mechanical method is: the fibers are extracted by physical method, the waste leather is first put into an opening device for opening process, a certain amount of auxiliary agent is added to tear the waste leather to a certain extent, accelerate the penetration of the auxiliary agent and the swelling of the waste leather, and improve the opening rate, and then put into a fiber extraction device to obtain secondary collagen fibers; the principle of chemical method is: the hydrolysis reaction equilibrium of chromium complex will move to the dissociation direction under acidic conditions, and the acid radical will form complex with chromium ion, so as to separate the combination of carboxyl in collagen fibers and chromium complex, thereby obtaining secondary collagen fibers.

[0026] Preferably, the solute in the alkali solution in step 1) is at least one of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0027] Preferably, the concentration of the solute in the alkali solution in step 1) is 0.01mol / L-0.05mol / L.

[0028] Preferably, the impregnation treatment in step 1) is carried out at a temperature of 70-100 DEG C and a stirring speed of 400-600 r / min, and the impregnation treatment is carried out for 4-6 hours.

[0029] Preferably, the hydrothermal reaction in step 2) is carried out at a temperature of 150-180 DEG C, and the reaction is carried out for 6-8 hours.

[0030] Preferably, the product separation in step 2) is carried out by dialysis, and the dialysis is followed by freeze-drying.

[0031] Preferably, the freeze-drying is carried out for 36-48 hours.

[0032] Preferably, the mixing in step 3) is carried out by stirring at a stirring speed of 400-600 r / min for 0.5-4 hours.

[0033] Preferably, the drying in step 3) is carried out at a temperature of 100-120 DEG C for 4-12 hours.

[0034] A preparation method of the photocatalytic coating comprises the following steps:

[0035] The light-transmitting resin is dissolved in water, and then the carbon quantum dot modified nano-titanium dioxide is added and mixed to obtain the photocatalytic coating.

[0036] A lamp comprises a lens, and an inner surface of the lens is covered with a coating layer made of the photocatalytic coating.

[0037] Preferably, the coating layer is made by the following method: the photocatalytic coating is coated on the inner surface of the lens, and then dried and cured by ultraviolet light.

[0038] Preferably, the coating is carried out by one of spraying, dipping, spin coating, blade coating and electrophoretic deposition.

[0039] Preferably, the drying is carried out at a temperature of 50-70 DEG C for 4-12 hours.

[0040] Preferably, the ultraviolet light curing is carried out for 30-60 minutes.

[0041] The photocatalytic coating of the present application can form a coating layer with photocatalytic degradation effect on the inner surface of the lens of the lamp, the coating layer can degrade the oil stains attached to the inner surface of the lens of the lamp through photocatalytic reaction, the lens of the lamp can maintain high light transmittance, and the service life of the lamp can be effectively prolonged.

[0042] Specifically,

[0043] 1) The photocatalytic coating of the present application adds carbon quantum dots modified nano-titanium dioxide, carbon quantum dots are firmly attached to the surface of nano-titanium dioxide particles through chemical modification, not only improves the light absorption capacity of nano-titanium dioxide (for example: expands the light absorption range of nano-titanium dioxide; enhances the absorption capacity of nano-titanium dioxide in the visible light region), but also improves the separation efficiency of photo-generated carriers (carbon quantum dots can effectively capture and transfer photo-generated electrons, reduce the recombination of electron-hole pairs, and improve the utilization efficiency of photo-generated carriers), enhances the photocatalytic performance of the formed coating, and can more efficiently degrade organic pollutants;

[0044] 2) The photocatalytic coating of the present application can impart high-efficiency and long-lasting oil degradation effect to the lens of the lamp, improve the light transmittance of the lens of the lamp, and effectively prolong the service life of the lamp;

[0045] 3) The photocatalytic coating of the present application has simple formula, safety and environmental protection, and no damage to the surface of the lens of the lamp, and is suitable for large-scale industrial production and application. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 SEM image of nano-titanium dioxide in Example 1.

[0047] Figure 2 AFM image of carbon quantum dots in Example 1.

[0048] Figure 3 Figure of oil degradation effect test results of the coating formed by the photocatalytic coating of Examples 1-5 and Comparative Examples. DETAILED DESCRIPTION

[0049] The present application will be further explained and described below in conjunction with specific examples.

[0050] Example 1:

[0051] A photocatalytic coating, the composition of which is shown in the following table:

[0052] Table 1 Composition table of a photocatalytic coating

[0053]

[0054]

[0055] Note:

[0056] The carbon quantum dots modified nano-titanium dioxide is prepared by the following steps:

[0057] 1) 20 g of secondary collagen fibers were added to 480 mL of a sodium hydroxide solution with a concentration of 0.02 mol / L, and then immersed at a temperature of 70°C and a stirring speed of 400 r / min for 5 h to obtain a secondary collagen fiber extract;

[0058] 2) The secondary collagen fiber extract was heated to 180°C and reacted for 8 h, and then the product was dialyzed against deionized water for 48 h, and then freeze-dried at -40°C for 48 h to obtain carbon quantum dots (CQDs; particle size ≤ 10 nm);

[0059] 3) 1 g of nano-titanium dioxide (20 nm-100 nm) and 0.1 g of carbon quantum dots were added to 100 mL of deionized water, and then stirred at a stirring speed of 400 r / min for 30 min, and then dried at 100°C for 6 h to obtain carbon quantum dot-modified nano-titanium dioxide.

[0060] The scanning electron microscope (SEM) image of the nano-titanium dioxide in this example is shown in Figure 1 , and the atomic force microscope (AFM) image of the carbon quantum dots is shown in Figure 2 .

[0061] As can be seen from Figure 1 , the particle size of the nano-titanium dioxide is 20 nm-100 nm.

[0062] As can be seen from Figure 2 , the carbon quantum dots are oblate spheroids with a particle size of less than 10 nm.

[0063] The preparation method of the above-mentioned photocatalytic coating is as follows:

[0064] Polyvinyl alcohol was added to water, and then stirred at a temperature of 70°C and a stirring speed of 500 r / min until the polyvinyl alcohol was completely dissolved, and then carbon quantum dot-modified nano-titanium dioxide was added and stirred for another 30 min to obtain the photocatalytic coating.

[0065] Example 2:

[0066] A photocatalytic coating, the composition of which is shown in the following table:

[0067] Table 2 Composition table of a photocatalytic coating

[0068]

[0069] Note:

[0070] The carbon quantum dot-modified nano-titanium dioxide was prepared by the following steps:

[0071] The carbon quantum dot modified nano-titanium dioxide was prepared by the following steps:

[0072] The preparation method of the above-mentioned photocatalytic coating is as follows:

[0073] The polyvinyl alcohol was added into water, and stirred at a temperature of 80°C and a stirring speed of 500 r / min until the polyvinyl alcohol was completely dissolved. Then, the carbon quantum dot modified nano-titanium dioxide was added and stirred for another 30 min, to obtain the photocatalytic coating.

[0074] Example 3:

[0075] A photocatalytic coating, the composition of which is shown in the following table:

[0076] Table 3 Composition table of a photocatalytic coating

[0077]

[0078] Note:

[0079] The carbon quantum dot modified nano-titanium dioxide was prepared by the following steps:

[0080] The carbon quantum dot modified nano-titanium dioxide was prepared by the following steps:

[0081] The preparation method of the above-mentioned photocatalytic coating is as follows:

[0082] The polyvinyl alcohol was added into water, and stirred at a temperature of 90°C and a stirring speed of 500 r / min until the polyvinyl alcohol was completely dissolved. Then, the carbon quantum dot modified nano-titanium dioxide was added and stirred for another 30 min, to obtain the photocatalytic coating.

[0083] Example 4:

[0084] A photocatalytic coating, the composition of which is shown in the following table:

[0085] Table 4 Composition table of a photocatalytic coating

[0086]

[0087] Note:

[0088] The carbon quantum dot modified nano-titanium dioxide is prepared by the following steps:

[0089] 1 g of nano-titanium dioxide (particle size of 20-100 nm) and 0.15 g of carbon quantum dots (same as in Example 1) are added to 100 mL of deionized water, and stirred at a stirring speed of 400 r / min for 30 min, and then dried at 100°C for 6 h to obtain the carbon quantum dot modified nano-titanium dioxide.

[0090] The preparation method of the above photocatalytic coating is as follows:

[0091] Polyvinyl alcohol is added to water, and stirred at a temperature of 70°C and a stirring speed of 500 r / min until the polyvinyl alcohol is completely dissolved, and then the carbon quantum dot modified nano-titanium dioxide is added and stirred for another 30 min to obtain the photocatalytic coating.

[0092] Example 5:

[0093] A photocatalytic coating, the composition of which is shown in the following table:

[0094] Table 5 Composition table of a photocatalytic coating

[0095]

[0096] Note:

[0097] The carbon quantum dot modified nano-titanium dioxide is prepared by the following steps:

[0098] 1 g of nano-titanium dioxide (particle size of 20-100 nm) and 0.3 g of carbon quantum dots (same as in Example 1) are added to 100 mL of deionized water, and stirred at a stirring speed of 400 r / min for 30 min, and then dried at 100°C for 6 h to obtain the carbon quantum dot modified nano-titanium dioxide.

[0099] The preparation method of the above photocatalytic coating is as follows:

[0100] Polyvinyl alcohol is added to water, and stirred at a temperature of 90°C and a stirring speed of 500 r / min until the polyvinyl alcohol is completely dissolved, and then the carbon quantum dot modified nano-titanium dioxide is added and stirred for another 30 min to obtain the photocatalytic coating.

[0101] Comparative Example:

[0102] A photocatalytic coating, the composition of which is shown in the following table:

[0103] Table 6 Composition table of a photocatalytic coating

[0104]

[0105]

[0106] The preparation method of the above photocatalytic coating is as follows:

[0107] The polyvinyl alcohol is added into water, and then stirred at a temperature of 70°C and a stirring speed of 500 r / min until the polyvinyl alcohol is completely dissolved. Then, the nano-titanium dioxide is added and stirred for another 30 min to obtain the photocatalytic coating.

[0108] Performance test:

[0109] The photocatalytic coatings of Examples 1-5 and the comparative example are evenly coated (the coating methods of the photocatalytic coatings of Examples 1-5 and the comparative example are spraying, dipping, spin coating, doctor blade coating, electrophoretic deposition and spraying, respectively) on the inner surface of a clean lamp lens, and then the lens is dried in an oven at 60°C for 4 h. Then, the lens is irradiated with ultraviolet light for 30 min, and then the surface of the lens coated with the coating is coated with lubricating oil. Then, the lens is subjected to light irradiation under sunlight, and the oil degradation of the surface of the lens is measured. The test results are shown in the following table (the corresponding oil degradation effect test results are shown in the following figures): Figure 3

[0110] Table 7 Test results of oil degradation effect of the coating formed by the photocatalytic coating

[0111]

[0112]

[0113] Note:

[0114] Degradation rate (%) = (initial oil weight - residual oil weight) / initial oil weight x 100%.

[0115] It can be seen from Table 7 and Figure 3 that:

[0116] 1) The coatings formed by the photocatalytic coatings of Examples 1-5 all exhibit high oil degradation efficiency, especially the coating formed by the photocatalytic coating of Example 5, which has a degradation rate of 90% after 8 h, while the coating formed by the photocatalytic coating of the comparative example has a degradation rate of only 50% after 8 h, which is increased by 40%. This indicates that the carbon quantum dot modified nano-titanium dioxide has a significantly better photocatalytic degradation effect than the unmodified nano-titanium dioxide.

[0117] 2) The coatings formed by the photocatalytic coatings of Examples 1-5 all show obvious oil degradation effect within the first 4 h, with a degradation rate of more than 50%. Moreover, the oil degradation rates of the coatings formed by the photocatalytic coatings of Examples 1-5 are all significantly higher than that of the coating formed by the photocatalytic coating of the comparative example at each time period. This indicates that the modification effect of the carbon quantum dots on the nano-titanium dioxide is significant. ​

[0118] 3) Different coating methods have a significant impact on the degradation effect of the coating, wherein the coating formed by electrophoretic deposition (Example 5) and dip coating (Example 2) exhibits the best degradation performance;

[0119] In conclusion, the photocatalytic coating of the present application coated on the inner surface of the lamp lens can form a coating with photocatalytic degradation effect, which can degrade the oil stains attached to the inner surface of the lamp lens through photocatalytic reaction, can keep the lamp lens high light transmittance, and finally can effectively prolong the service life of the lamp.

[0120] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. A photocatalytic coating, characterized by, The composition comprises the following components by weight percentage: The light-transmitting resin: 0.5% to 2%; The carbon quantum dot modified nano-titanium dioxide: 0.5% to 2%; The water: 96% to 99%; The light-transmitting resin is polyvinyl alcohol; The carbon quantum dot modified nano-titanium dioxide is made by a preparation method comprising the following steps: 1) immersing secondary collagen fibers in an alkali solution for impregnation treatment to obtain a secondary collagen fiber extract; 2) heating the secondary collagen fiber extract for hydrothermal reaction, and then separating the product to obtain carbon quantum dots; 3) adding nano-titanium dioxide and carbon quantum dots into a solvent, mixing thoroughly, and then drying to obtain the carbon quantum dot modified nano-titanium dioxide.

2. The photocatalytic coating according to claim 1, characterized in that: The weight ratio of the nano-titanium dioxide to the carbon quantum dots in the carbon quantum dot modified nano-titanium dioxide is 1:0.05 to 0.

5.

3. The photocatalytic coating according to claim 2, characterized in that: The particle size of the nano-titanium dioxide in the carbon quantum dot modified nano-titanium dioxide is 20nm to 100nm; and the particle size of the carbon quantum dots in the carbon quantum dot modified nano-titanium dioxide is ≤10nm.

4. The photocatalytic coating according to claim 1, characterized in that: In step 1), the secondary collagen fibers are recycled collagen fibers made from waste leather by mechanical or chemical methods; in step 1), the solute in the alkali solution is at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide; and in step 1), the concentration of the solute in the alkali solution is 0.01mol / L to 0.05mol / L.

5. The photocatalytic coating according to claim 1, characterized in that: In step 1), the impregnation treatment is performed at a temperature of 70℃ to 100℃ and a stirring speed of 400r / min to 600r / min, and the impregnation treatment time is 4h to 6h.

6. The photocatalytic coating according to claim 1, characterized in that: In step 2), the hydrothermal reaction is performed at a temperature of 150℃ to 180℃, and the reaction time is 6h to 8h.

7. A method for producing the photocatalytic coating as claimed in any one of claims 1 to 6, characterized in that, The method comprises the following steps: Dissolving the light-transmitting resin in water, then adding the carbon quantum dot modified nano-titanium dioxide and mixing to obtain the photocatalytic coating.

8. A luminaire characterized by, The composition comprises a lens; and the inner surface of the lens is covered with a coating layer made of the photocatalytic coating according to any one of claims 1 to 6.

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