Preparation method of low-valence titanium oxide and graphene oxide composite photo-thermal coating

Abstract

The invention discloses a preparation method of a low-valence titanium oxide and graphene oxide composite photo-thermal coating, and belongs to the field of photo-thermal coating preparation. A preparation method of a low-valence titanium oxide and graphene oxide composite photo-thermal coating comprises the following steps that firstly, Ti2O3 and Ti3O5 raw materials are subjected to ball milling till the diameter is 300 nm or below, and a low-valence titanium oxide mixture is prepared; 2, performing suction filtration on the low-valence titanium oxide mixture, and performing vacuum preparation to obtain powder; 3, mixing and modifying the powder, graphene oxide and a silane coupling agent, and preparing modified powder; 4, mixing an organic solvent dissolved with a film-forming agent with the modified powder to prepare a photo-thermal film-forming solution; 5, spraying the photo-thermal film forming liquid to the surface of the glass according to the standard; according to the invention, the raw material cost of the photo-thermal coating can be reduced, and the environmental friendliness and photo-thermal conversion efficiency of the photo-thermal coating can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photothermal coating preparation, and in particular to a method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating. Background Art

[0002] Solar energy is an inexhaustible renewable energy source. Finding good photothermal conversion coating materials is an important way to alleviate the energy crisis and achieve the "dual carbon" goal. At present, organic compound-based, ceramic-based, metal nanoparticle-based, carbon-based and semiconductor-based photothermal conversion coating materials have been widely studied. The photothermal conversion components of common photothermal conversion coatings on the market are mainly gold, silver, copper, chromium, molybdenum, zinc sulfide, lead sulfide, nickel sulfide, aluminum oxide, and copper oxide. The raw materials are expensive, and some raw materials are highly toxic. In addition, there are a series of disadvantages such as high price, poor thermal stability, and complex preparation. Secondly, photothermal conversion coatings are mainly obtained by electroplating, vacuum magnetron sputtering, and vacuum coating. The equipment is expensive, the raw material loss is large, and the energy consumption is high. Therefore, a photothermal conversion coating material with excellent preparation performance, low price, and simple synthesis method is a challenge to obtain solar energy resources and a problem that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to solve the problems of high cost, low safety and complex preparation of photothermal coating materials in the prior art, and to propose a method for preparing a low-cost titanium oxide and graphene oxide composite photothermal coating.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating comprises the following steps: step one: ball-milling Ti2O3 and Ti3O5 raw materials to a diameter of less than 300 nm to prepare a low-valent titanium oxide mixture; step two: filtering the low-valent titanium oxide mixture and preparing it into powder by vacuum; step three: mixing and modifying the powder and graphene oxide with a silane coupling agent to prepare a modified powder; step four: mixing an organic solvent containing a film-forming agent with the modified powder to prepare a photothermal film-forming liquid; and step five: spraying the photothermal film-forming liquid onto a glass surface according to standards.

[0006] Preferably, the ball milling in step one is divided into three stages, including: stage one: rotation speed of 200-300r / min, time of not less than 6 hours; stage two: rotation speed of 400-500r / min, time of not less than 10 hours; stage three: rotation speed of 600-700r / min, time of not less than 14 hours.

[0007] Preferably, the vacuum preparation conditions in step 2 are: temperature range is 70-90° C., and drying time is 7-12 hours.

[0008] Preferably, step three further comprises: A: ultrasonically dispersing the mixture; B: controlling the pH of the mixture using an alkaline solution; C: stirring the mixture at a constant temperature; and D: vacuum filtering and drying the mixture.

[0009] Furthermore, the pH value of the mixture ranges from 9.5 to 10.5.

[0010] Furthermore, the mixture is stirred for no less than 12 hours at a temperature ranging from 50°C to 70°C.

[0011] Preferably, the silane coupling agent in step three is one of KH-550, KH-560 and KH-570.

[0012] Preferably, in step 4, the film-forming agent is one of polyvinyl acetate, polyvinyl butyral and polyurea, and the organic solvent is acetone or ethyl acetate.

[0013] Preferably, in step 4, the ratio of the film-forming agent to the organic solvent is 1-1.5:20-25.

[0014] Preferably, the spraying standard in step five is: pressure: 0.3-0.7 MPa; dosage: 40-120 ml / ㎡.

[0015] Compared with the prior art, the present invention provides a method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating, which has the following beneficial effects:

[0016] 1. The preparation method of the low-cost titanium oxide and graphene oxide composite photothermal coating does not contain rare and precious metals such as gold, silver, and molybdenum in the raw materials, so the cost of raw materials is reduced. The photothermal film is obtained by the spraying method, the equipment is simple, the operation is simple, and the cost of the film forming process is greatly reduced;

[0017] 2. The preparation method of the low-cost titanium oxide and graphene oxide composite photothermal coating is safe, non-toxic and environmentally friendly because the photothermal coating is mainly composed of Ti2O3, Ti3O5 and graphene oxide. Traditional photothermal coatings contain toxic ingredients such as chromium, molybdenum, zinc sulfide, lead sulfide, nickel sulfide, etc., which pose certain risks to human health and environmental safety.

[0018] 3. The preparation method of the low-valent titanium oxide and graphene oxide composite photothermal coating is as follows:

[0019] The parts not involved in the device are the same as the existing technology or can be implemented by the existing technology. The present invention uses Ti2O3 and Ti3O5, which are low-priced, safe and non-toxic, and have high-efficiency absorption characteristics of sunlight, as the main photothermal components, reducing the raw material cost of the photothermal coating and increasing the environmental friendliness of the photothermal coating. Graphene oxide, which is safe and non-toxic and has full-spectrum absorption characteristics, is used as a secondary photothermal component to synergistically improve the photothermal conversion efficiency of the composite coating. Ti2O3, Ti3O5 and graphene oxide are surface-modified by a silane coupling agent to enhance the compatibility with organic solvents and film-forming agents. The photothermal coating is obtained by a spraying method. The spraying equipment is cheap and simple, the spraying process is simple and easy to operate, the raw material loss is small, the process energy consumption is low, and the preparation cost of the photothermal film is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of UV-visible-near infrared light absorption and surface temperature change of the present invention Figure 1 ;

[0021] Figure 2 Schematic diagram of UV-visible-near infrared light absorption and surface temperature change of the present invention Figure 2 ;

[0022] Figure 3 Schematic diagram of UV-visible-near infrared light absorption and surface temperature change of the present invention Figure 3 ;

[0023] Figure 4 Schematic diagram of UV-visible-near infrared light absorption and surface temperature change of the present invention Figure 4 . DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0025] Embodiment 1:

[0026] Reference Figure 1-Figure 4A method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating comprises the following steps: step 1: ball-milling Ti2O3 and Ti3O5 raw materials to a diameter of less than 300 nm to prepare a low-valent titanium oxide mixture; step 2: filtering the low-valent titanium oxide mixture and preparing it into powder in a vacuum; step 3: mixing and modifying the powder and graphene oxide with a silane coupling agent to prepare a modified powder; step 4: mixing an organic solvent containing a film-forming agent with the modified powder to prepare a photothermal film-forming liquid; step 5: spraying the photothermal film-forming liquid onto the glass surface according to the standard.

[0027] The ball milling in step 1 is divided into three stages, including: stage 1: rotation speed is 200-300r / min, time is not less than 6 hours; stage 2: rotation speed is 400-500r / min, time is not less than 10 hours; stage 3: rotation speed is 600-700r / min, time is not less than 14 hours.

[0028] The vacuum preparation conditions in step 2 are: temperature range of 70-90° C., drying time of 7-12 hours, and here, preferably the temperature is 80° C., and the drying time is 7 hours.

[0029] Step three also includes: A: ultrasonically dispersing the mixture; B: controlling the pH of the mixture using an alkaline solution; C: stirring the mixture at a constant temperature; and D: vacuum filtering and drying the mixture.

[0030] The pH value of the mixture ranges from 9.5 to 10.5, wherein a pH value of 10 is preferred.

[0031] The mixture is stirred for no less than 12 hours, the temperature range is 50-70°C, and the stirring speed is 400-600r / min. Here, the preferred temperature is 60°C.

[0032] The third silane coupling agent is one of KH-550, KH-560 and KH-570.

[0033] In step 4, the film-forming agent is one of polyvinyl acetate, polyvinyl butyral and polyurea, and the organic solvent is acetone or ethyl acetate.

[0034] In step 4, the ratio of the film-forming agent to the organic solvent is 1-1.5:20-25.

[0035] The spraying standards in step five are: pressure: 0.3-0.7MPa; dosage: 40-120ml / ㎡.

[0036] The preparation method of the photothermal coating is simple, low-cost, safe, environmentally friendly, easy to operate, requires cheap equipment, and is suitable for large-scale production. It has excellent full-spectrum absorption of sunlight and high photothermal conversion efficiency, and has potential application value in solar water heaters, photothermal deicing, seawater desalination, sewage purification, disinfection and sterilization, and other fields.

[0037] Ti2O3 and Ti3O5, which are inexpensive, safe and non-toxic and have high-efficiency absorption characteristics for sunlight, are used as the main photothermal components to reduce the raw material cost of the photothermal coating and increase the environmental friendliness of the photothermal coating. Graphene oxide, which is safe and non-toxic and has full-spectrum absorption characteristics, is used as a secondary photothermal component to synergistically improve the photothermal conversion efficiency of the composite coating. The surface of Ti2O3, Ti3O5 and graphene oxide is modified by a silane coupling agent to enhance the compatibility with organic solvents and film-forming agents. The photothermal coating is obtained by spraying. The spraying equipment is cheap and simple, the spraying process is simple and easy to operate, the raw material loss is small, the process energy consumption is low, and the preparation cost of the photothermal film is greatly reduced.

[0038] (1) The raw materials do not contain rare and precious metals such as gold, silver, and molybdenum, which reduces the cost of raw materials. The photothermal film is obtained by spraying, which has simple equipment and easy operation, and the cost of film forming process is greatly reduced;

[0039] (2) Photothermal coatings are mainly composed of Ti2O3, Ti3O5 and graphene oxide, which are safe, non-toxic and environmentally friendly. Traditional photothermal coatings contain toxic ingredients such as chromium, molybdenum, zinc sulfide, lead sulfide, nickel sulfide, etc., which pose certain risks to human health and environmental safety.

[0040] In addition, the following details are added: in step 1, low-valent titanium oxide and deionized water are mixed in a mass ratio of 1-3:10, in step 3, deionized water: anhydrous ethanol water: silane coupling agent are mixed in a ratio of 20-40:100:10, and the ultrasonic dispersion time is 1-3 hours to obtain the following embodiment.

[0041] Embodiment 2:

[0042] Reference Figure 1 Based on the first embodiment, a method for preparing a composite photothermal coating is specifically proposed, comprising the following steps:

[0043] Step 1: Put 3g of Ti2O3, 3g of Ti3O5 and 20ml of deionized water into a ball mill, first ball mill at a speed of 300r / min for 6 hours, then ball mill at a speed of 450r / min for 10 hours, and finally ball mill at a speed of 700r / min for 14 hours to prepare a low-valent titanium oxide mixture, i.e., a ball milling liquid;

[0044] Step 2: taking out the ball milling liquid from the ball milling jar, filtering it, drying the low-valent titanium oxide mixture in a vacuum drying oven at 80° C. for 7 hours, and then grinding the agglomerated low-valent titanium oxide mixture into powder in a mortar;

[0045] Step 3: After mixing 30 ml of deionized water and 100 ml of anhydrous ethanol, 10 ml of KH-560 was added, and then 5 g of low-valent titanium oxide mixture ground powder and 0.5 g of graphene oxide were added. After ultrasonic dispersion for 1 hour, sodium hydroxide solution was added to adjust the solution pH to 10, and then stirred in a constant temperature oil bath at 60° C. for 12 hours. After vacuum filtration, the surface-modified mixed solution was dried in a vacuum oven at 60° C. for 10 hours, and then the agglomerated surface-modified low-valent titanium oxide / graphene mixture was ground in a mortar to prepare a modified powder;

[0046] Step 4: Put 5g of polyvinyl acetate into 100ml of acetone, dissolve it at a speed of 400r / min for 4 hours, put in 5g of surface-modified low-valent titanium oxide / graphene mixture powder, ultrasonically disperse it for 2 hours, and stir it at a speed of 700r / min for 4 hours to obtain a photothermal film-forming solution;

[0047] Step 5: Use a spray gun to spray the photothermal film-forming liquid onto the glass surface at a pressure of 0.4-0.6MPa, with a dosage of 100ml per square meter. After spraying, dry it in ventilation conditions for 4 hours. After the solvent is completely evaporated, a low-valent titanium oxide / graphene oxide composite photothermal coating is obtained.

[0048] Embodiment three:

[0049] Reference Figure 2 Based on the first embodiment, a method for preparing a composite photothermal coating is specifically proposed, comprising the following steps:

[0050] Step 1: Put 4g of Ti2O3, 2g of Ti3O5 and 20ml of deionized water into a ball mill, first ball mill at a speed of 300r / min for 6 hours, then ball mill at a speed of 500r / min for 10 hours, and finally ball mill at a speed of 700r / min for 14 hours to prepare a low-valent titanium oxide mixture, i.e., a ball milling liquid;

[0051] Step 2: taking out the ball milling liquid from the ball milling jar, filtering it, drying the low-valent titanium oxide mixture in a vacuum drying oven at 80° C. for 7 hours, and then grinding the agglomerated low-valent titanium oxide mixture into powder in a mortar;

[0052] Step 3: After mixing 20 ml of deionized water and 100 ml of anhydrous ethanol, add 10 ml of KH-550, then add 6 g of low-valent titanium oxide mixture ground powder and 0.8 g of graphene oxide, after ultrasonic dispersion for 1 hour, add sodium hydroxide solution to adjust the solution pH to 10, and then stir in a constant temperature oil bath at 60°C for 12 hours. After the surface-modified mixed solution is filtered, it is dried in a vacuum oven at 60°C for 10 hours, and the agglomerated surface-modified low-valent titanium oxide / graphene mixture is ground in a mortar to prepare a modified powder;

[0053] Step 4: 7.5 g of polyvinyl butyral was put into 120 ml of ethyl acetate, dissolved at a speed of 400 r / min for 4 hours, 6.8 g of surface-modified low-valent titanium oxide / graphene powder was added, ultrasonically dispersed for 2 hours, and stirred at a speed of 700 r / min for 4 hours to obtain a photothermal film-forming solution;

[0054] Step 5: Use a spray gun to spray the photothermal film-forming liquid onto the glass surface at a pressure of 0.4-0.6MPa. The amount used per square meter is 120ml. After spraying, dry it under ventilation conditions for 4 hours. After the solvent is completely evaporated, a low-valent titanium oxide / graphene oxide composite photothermal coating is obtained.

[0055] Embodiment 4:

[0056] Reference Figure 3 Based on the first embodiment, a method for preparing a composite photothermal coating is specifically proposed, comprising the following steps:

[0057] Step 1: Put 1.5g of Ti2O3, 4.5g of Ti3O5 and 20ml of deionized water into a ball mill, first ball mill at a speed of 300r / min for 6 hours, then ball mill at a speed of 450r / min for 10 hours, and finally ball mill at a speed of 700r / min for 14 hours to prepare a low-valent titanium oxide mixture, i.e., a ball milling liquid;

[0058] Step 2: taking out the ball milling liquid from the ball milling jar, filtering it, drying the low-valent titanium oxide mixture in a vacuum drying oven at 80° C. for 7 hours, and then grinding the agglomerated low-valent titanium oxide mixture into powder in a mortar;

[0059] Step 3: After mixing 30 ml of deionized water and 100 ml of anhydrous ethanol, add 10 ml of KH-560, then add 6 g of low-valent titanium oxide mixture ground powder and 1 g of graphene oxide, after ultrasonic dispersion for 1 hour, add sodium hydroxide solution to adjust the solution pH to 10, and then stir in a constant temperature oil bath at 60°C for 12 hours. After the surface-modified mixed solution is filtered, it is dried in a vacuum oven at 60°C for 10 hours, and the agglomerated surface-modified low-valent titanium oxide / graphene is ground in a mortar to prepare a modified powder;

[0060] Step 4: 5 g of polyurea was put into 100 ml of ethyl acetate, dissolved at a speed of 400 r / min for 4 hours, 7 g of surface-modified low-valent titanium oxide / graphene mixture powder was added, ultrasonically dispersed for 2 hours, and stirred at a speed of 700 r / min for 4 hours to obtain a photothermal film-forming solution;

[0061] Step 5: Use a spray gun to spray the photothermal film-forming liquid onto the glass surface at a pressure of 0.4-0.6MPa, with a dosage of 100ml per square meter. After spraying, dry it in ventilation conditions for 4 hours. After the solvent is completely evaporated, a low-valent titanium oxide / graphene oxide composite photothermal coating is obtained.

[0062] Embodiment five:

[0063] Reference Figure 4 Based on the first embodiment, a method for preparing a composite photothermal coating is specifically proposed, comprising the following steps:

[0064] Step 1: Put 3g of Ti2O3, 4.5g of Ti3O5 and 30ml of deionized water into a ball mill, first ball mill at a speed of 300r / min for 6 hours, then ball mill at a speed of 450r / min for 10 hours, and finally ball mill at a speed of 700r / min for 14 hours to prepare a low-valent titanium oxide mixture, i.e., a ball milling liquid;

[0065] Step 2: taking out the ball milling liquid from the ball milling jar, filtering it, drying the low-valent titanium oxide mixture in a vacuum drying oven at 80° C. for 7 hours, and then grinding the agglomerated low-valent titanium oxide mixture into powder in a mortar;

[0066] Step 3: After mixing 20 ml of deionized water and 100 ml of anhydrous ethanol, add 10 ml of KH-560, then add 7 g of low-valent titanium oxide mixture ground powder and 0.5 g of graphene oxide, after ultrasonic dispersion for 1 hour, add sodium hydroxide solution to adjust the solution pH to 10, and then stir in a constant temperature oil bath at 60°C for 12 hours. After the surface-modified mixed solution is filtered, it is dried in a vacuum oven at 60°C for 10 hours, and the agglomerated surface-modified low-valent titanium oxide / graphene is ground in a mortar to prepare a modified powder;

[0067] Step 4: 7.5 g of polyvinyl acetate was put into 120 ml of acetone, dissolved at a speed of 400 r / min for 4 hours, 7.5 g of surface-modified low-valent titanium oxide / graphene mixture powder was added, ultrasonically dispersed for 2 hours, and stirred at a speed of 700 r / min for 4 hours to obtain a photothermal film-forming solution;

[0068] Step 5: Use a spray gun to spray the photothermal film-forming liquid onto the glass surface at a pressure of 0.4-0.6MPa. The amount used per square meter is 120ml. After spraying, dry it under ventilation conditions for 4 hours. After the solvent is completely evaporated, a low-valent titanium oxide / graphene oxide composite photothermal coating is obtained.

[0069] In the above-mentioned embodiments 2 to 5, it can be summarized as follows:

[0070]

[0071] From the table and attached Figure 1-Figure 4 It can be seen that the photothermal coating can ensure that the light absorption rate is above 92% when the wavelength is below 2000nm, and the photothermal coating prepared in Example 4 and Example 5 can still maintain an absorption rate of more than 92% in some wavelengths above 2000nm; and under the intensity of 1 sun, the temperature of the photothermal coating prepared in Example 2 and Example 5 can reach 107°C and above, which is much higher than most traditional photothermal coatings; in summary, the photothermal coating prepared in Example 5 can be preferred, which not only can ensure a higher absorption rate and temperature, but also uses less graphene oxide components, which can greatly save costs.

[0072] In the present invention, firstly, Ti2O3 and Ti3O5 are both low-valent oxides of titanium, which are safe, non-toxic, and inexpensive, and have the characteristics of semiconductor materials and metal materials. Their bandgap widths are 1.54eV and 2.7eV respectively, and they can absorb most wavelengths of sunlight and have very high photothermal conversion efficiency; secondly, graphene oxide has the characteristics of safety and non-toxicity, micro-nano structure and full-spectrum absorption, and has been widely used in the field of photothermal conversion in recent years. However, due to its high price, it is mainly used as a secondary photothermal component in the prepared product to synergistically enhance the photothermal conversion efficiency of the main photothermal component to ensure low cost and high conversion efficiency; finally, the preparation method adopts a pre-prepared photothermal film-forming liquid, and a photothermal conversion coating can be obtained by a simple and efficient spraying method. The spraying equipment is cheap and simple, and the spraying process is simple and easy to operate, which greatly reduces the preparation cost of the photothermal conversion film.

[0073] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating, characterized in that: The steps include: Step 1: ball-milling Ti2O3 and Ti3O5 raw materials to a diameter of less than 300 nm to prepare a low-valent titanium oxide mixture; Step 2: Filtering the low-valent titanium oxide mixture and preparing it into powder under vacuum; Step 3: Mixing and modifying the powder, graphene oxide and silane coupling agent to prepare modified powder; Step 4: Mixing the organic solvent containing the film-forming agent with the modified powder to prepare a photothermal film-forming liquid; Step 5: Spray the photothermal film-forming liquid onto the glass surface according to the standard.

2. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: The ball milling in step 1 is divided into three stages, including: Stage 1: speed is 200-300r / min, time is not less than 6 hours; Stage 2: The speed is 400-500r / min, and the time is not less than 10 hours; Stage three: speed is 600-700r / min, time is not less than 14 hours.

3. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: The vacuum preparation conditions in step 2 are: temperature range of 70-90° C., and drying time of 7-12 hours.

4. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: Step three also includes: A: Ultrasonic dispersion of the mixture; B: Use alkaline solution to control the pH of the mixture; C: Stir the mixture at a constant temperature; D: The mixture was vacuum filtered and dried.

5. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 4, characterized in that: The pH value of the mixture ranged from 9.5 to 10.

5.

6. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 4, characterized in that: The mixture is stirred for no less than 12 hours at a temperature ranging from 50 to 70°C.

7. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: The third silane coupling agent is one of KH-550, KH-560 and KH-570.

8. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: In step 4, the film-forming agent is one of polyvinyl acetate, polyvinyl butyral and polyurea, and the organic solvent is acetone or ethyl acetate.

9. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1 or 8, characterized in that: In step 4, the ratio of the film-forming agent to the organic solvent is 1-1.5:20-25.

10. The method for preparing a low-valent titanium oxide and graphene oxide composite photothermal coating according to claim 1, characterized in that: The spraying standards in step 5 are: Pressure: 0.3-0.7MPa; Dosage: 40-120ml / ㎡.

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