Photocatalytic self-cleaning nano ink and preparation method thereof

Abstract

The invention belongs to the technical field of photocatalytic self-cleaning materials, and particularly relates to photocatalytic self-cleaning nano-ink and a preparation method thereof.The preparation method comprises the steps that ethyl alcohol serves as a solvent, a first mixture of silicon tetrachloride and tetra-n-butyl titanate is prepared, under the stirring condition, first mixed liquid of ethyl alcohol and water is added into the first mixture, and TiO2 / SiO2 sol is prepared; an ethanol solution of SnCl4 is added into the TiO2 / SiO2 sol, under the stirring condition, a second mixed solution of ethanol and water is added, stirring reaction is carried out, a TiO2 / SiO2 / SnO2 nano-particle solution is obtained, a diluent is added, the photocatalytic self-cleaning nano-ink is prepared, the average particle size ranges from 10 nm to 20 nm, the contact angle between a self-cleaning film layer and water is smaller than 3 degrees, and the photocatalytic self-cleaning nano-ink belongs to a high-performance super-hydrophilic film and is free of organic matter and harmful substance. The ion polycondensation path is regulated and controlled through the hydrolysis rate, controllable synthesis of the nano material is achieved, and the photocatalytic performance of the material is improved.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic self-cleaning materials technology, specifically relating to a photocatalytic self-cleaning nano-ink and its preparation method. Background Technology

[0002] Research on self-cleaning materials has always been a hot topic in materials science, attracting the attention of many researchers. Based on different self-cleaning mechanisms, self-cleaning surfaces can be categorized into three types: superhydrophobic, superhydrophilic, and superoleophobic. Among these, superhydrophilic self-cleaning materials refer to materials whose surfaces can form a uniform water film, allowing dirt to automatically detach or degrade under the influence of rain, gravity, and wind.

[0003] Photovoltaic modules are exposed to outdoor environments for extended periods, making their glass surfaces susceptible to corrosion from dust, dirt, bird droppings, and other contaminants. Simultaneously, sodium and calcium components within the glass gradually leach out. To address this issue, current research primarily focuses on TiO2 photoinduced superhydrophilic materials. These materials form a photocatalytic self-cleaning film on the glass surface. Under light irradiation, organic and inorganic contaminants degrade through TiO2 photocatalysis and are subsequently removed from the glass surface by rainwater. One process involves preparing these materials as sol-gels; however, the particle size of sol-gels prepared using this method is uncontrollable, thus affecting the material's photocatalytic performance. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a photocatalytic self-cleaning nano-ink and its preparation method. This invention enables controllable synthesis of material particle size, and the material possesses high-performance superhydrophilic properties and is free of organic matter and harmful substances.

[0005] The present invention is specifically implemented through the following technical solutions.

[0006] This invention provides a method for preparing photocatalytic self-cleaning nano-ink, comprising the following steps: A first mixture of silicon tetrachloride and tetrabutyl titanate was prepared using ethanol as a solvent. Under stirring conditions, a first mixture of ethanol and water was added to the first mixture, and the stirring was continued to regulate the hydrolysis process of tetrabutyl titanate. Then, aging was carried out. Tetrabutyl titanate formed TiO2 through a hydrolysis-condensation reaction, and SiO2 coated the surface of the TiO2, yielding a TiO2 / SiO2 sol. The volume ratio of ethanol in the first mixture to ethanol in the first mixture to water in the first mixture was 22~36:20~25:1. The aging temperature was 20℃~70℃, and the aging time was 12h~24h. It should be noted that during the hydrolysis process, an appropriate amount of water was added to maintain a certain hydrolysis rate of tetrabutyl titanate, avoiding excessively rapid hydrolysis and particle size increase.

[0007] An ethanol solution of SnCl4 was added to a TiO2 / SiO2 sol to prepare a second mixture. Under stirring, a second mixture of ethanol and water was added to this second mixture, and the mixture was stirred. The reaction was then carried out at 90℃~120℃, allowing SnO2 to grow in situ and coat the SiO2 surface, resulting in a TiO2 / SiO2 / SnO2 nanoparticle solution. The order in which SiO2 and SnO2 coated TiO2 was controlled by introducing SiCl4 and SnCl4 stepwise.

[0008] A diluent was added to a TiO2 / SiO2 / SnO2 nanoparticle solution to adjust the concentration of TiO2 / SiO2 / SnO2 nanoparticles, thus preparing a photocatalytic self-cleaning nano-ink.

[0009] Preferably, in the first mixture, the ratio of silicon tetrachloride to ethanol is 1g:8.8mL~9mL; and the ratio of tetrabutyl titanate to ethanol is 1g:11mL~12mL.

[0010] Preferably, the mass ratio of tetrabutyl titanate to SnCl4 is 15~20:10~12; in the ethanol solution of SnCl4, the ratio of SnCl4 to ethanol is 1g:5mL.

[0011] Preferably, in the second mixture, the volume ratio of ethanol to water is 5:1, and the volume ratio of SnCl4 to the second mixture is 1g:18mL~20mL.

[0012] Preferably, in the step of preparing TiO2 / SiO2 sol, the stirring time is 1 hour.

[0013] Preferably, in the step of preparing TiO2 / SiO2 / SnO2 nanoparticle solution, the stirring time is 1 hour and the reaction time is 4 to 6 hours.

[0014] Preferably, the diluent is water, and the volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water is 1:5~10.

[0015] Preferably, the diluent is a third mixture of water and ethanol; the volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution: water in the third mixture: ethanol in the third mixture is 1:3~8:1~3.

[0016] This invention also provides a photocatalytic self-cleaning nano-ink, prepared using the above-described method. The photocatalytic self-cleaning nano-ink comprises a solvent and nanoparticles uniformly dispersed in the solvent. The nanoparticles have a core-shell structure, comprising TiO2, SiO2, and SnO2 from the inside out. The average particle size of the nanoparticles is 10-20 nm. The self-cleaning film layer made from the photocatalytic self-cleaning nano-ink has a contact angle of less than 3° with water. Furthermore, it contains no organic matter or harmful substances.

[0017] When self-cleaning materials are applied to photovoltaic modules, the photolysis index of the self-cleaning film reaches 44.2 nmol / (L・min), which can efficiently decompose organic stains; a dense nanofilm is formed on the surface of the module glass, which effectively inhibits the precipitation of sodium calcium in the glass and reduces glass fogging.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention proposes a method for preparing photocatalytic self-cleaning nano-ink. Using ethanol as a solvent, a first mixture of silicon tetrachloride and tetrabutyl titanate is prepared. Then, ethanol and water are added to regulate the hydrolysis process of tetrabutyl titanate. After aging, a TiO2 / SiO2 sol with SiO2 coated on the TiO2 surface is prepared. SnCl4 is then introduced into the system, followed by the addition of ethanol and water. A high-temperature reaction is carried out, allowing SnO2 to grow in situ and coat the SiO2 surface, forming TiO2 / SiO2 / SnO2 nanoparticles. This invention controls the titanium ion condensation pathway by controlling the hydrolysis rate, enabling precise control of the material particle size. The preparation process is highly controllable. It achieves rapid synthesis, crystallization, and particle size control of nanomaterials under mild conditions, which is beneficial for improving the stability of the material and thus enhancing its photocatalytic performance. The prepared self-cleaning film has a contact angle with water of less than 3°, belonging to a high-performance superhydrophilic film. It is also free of organic matter and harmful substances, exhibiting significant advantages in environmental protection and self-cleaning performance.

[0019] The method for regulating the hydrolysis rate of titanium ion condensation pathway proposed in this invention is the core of achieving controllable synthesis of nanomaterials. Specifically, its mechanism involves the hydrolysis-condensation kinetics regulation of tetrabutyl titanate. By precisely controlling the hydrolysis environment, such as the water and ethanol ratio, temperature, and aging time, the kinetics of Ti ion condensation are guided. 4+ TiO2 with specific morphology and particle size is formed and combined with SiO2 and SnO2 to form uniformly dispersed core-shell structured nanoparticles.

[0020] Tetrabutyl titanate undergoes hydrolysis in an aqueous ethanol solution to generate the titanium hydroxyl intermediate Ti-OH, which then forms TiO2 nanoparticles through a condensation reaction. The specific reaction formula is as follows: Hydrolysis reaction: Ti(OBu)₄ + nH₂O → Ti(OBu) 4−n (OH) n +nBuOH.

[0021] Dehydration condensation reaction: −Ti−OH + HO−Ti−→−Ti−O−Ti− + H2O.

[0022] De-alcoholization polycondensation reaction: −Ti−OBu + HO−Ti−→−Ti−O−Ti− + BuOH.

[0023] Parameters affecting the above process: Adding ethanol to the solvent can dilute the water concentration and reduce the hydrolysis rate. When the water content is low, tetrabutyl titanate hydrolyzes slowly, and the titanium hydroxyl intermediate tends to slowly condense into single molecules, forming small, uniformly dispersed nanoparticles. If the water content is too high, the hydrolysis rate accelerates, and titanium ions easily aggregate into larger particles or even agglomerate.

[0024] During low-temperature aging, molecular motion is slow, and condensation reactions are mainly directional growth, forming regular crystal forms. High-temperature aging accelerates molecular motion, promotes particle collision and fusion, and may lead to an increase in particle size. Extending the aging time can allow for more complete particle growth, but excessively long aging times may cause large particles to engulf smaller particles, resulting in an increase in the average particle size.

[0025] Under moderately high temperatures, the hydrolysis-condensation reaction rate accelerates, while simultaneously promoting the in-situ growth and recombination of SnO2, forming core-shell structured TiO2 / SiO2 / SnO2 composite nanoparticles from the inside out. This also facilitates the formation of highly active anatase TiO2. Excessively high temperatures lead to a transformation in the TiO2 crystal structure, with the anatase phase transforming into the rutile phase, affecting photocatalytic activity; conversely, excessively low temperatures result in incomplete reaction and insufficient particle crystallinity.

[0026] Therefore, at low hydrolysis rates, titanium ions polymerize slowly, resulting in numerous and uniform nucleation sites, forming small particles with a diameter of 10 nm to 20 nm; at high hydrolysis rates, aggregates are formed. This invention controls the order in which SiO2 and SnO2 coat TiO2 by introducing SiCl4 and SnCl4 in a stepwise manner. The semiconductor properties of SnO2 form a heterojunction with TiO2, promoting the separation of photogenerated electron-hole pairs and improving photocatalytic efficiency.

[0027] (2) This invention prepares TiO2 / SiO2 / SnO2 composite nanoparticle ink with controllable particle size. The nanoparticles are uniformly dispersed in the solvent, exhibiting good stability, which is beneficial for storage and use. A uniform and dense film layer is formed on the surface of the photovoltaic panel using a spraying process. The film layer has a high photolysis index, which can efficiently decompose organic stains. At the same time, it can isolate the glass from the atmospheric environment, avoiding contact with acidic and other harmful components in the atmosphere, and preventing the precipitation of sodium and calcium components in the glass. This eliminates the glass fogging phenomenon caused by the reaction of precipitated sodium and calcium with moisture, carbon dioxide, etc. in the air. In addition, for large-area surfaces such as photovoltaic panels, the nano-ink prepared by this invention can form a film layer on the surface using a spraying process. Compared with the current dip-coating method suitable for small glass products, it can better meet the production needs of photovoltaic modules. Moreover, this invention does not contain organic matter or harmful substances, and has significant advantages in terms of environmental protection and self-cleaning performance. Attached Figure Description

[0028] Figure 1Scanning electron microscope image of the photocatalytic self-cleaning nano-ink prepared in Example 1.

[0029] Figure 2 The image shows the hydrophilicity of the photocatalytic self-cleaning nano-ink prepared in Example 1. Detailed Implementation

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0031] Example 1 A method for preparing a photocatalytic self-cleaning nano-ink includes the following steps: Step 1: Under stirring conditions, mix 20g silicon tetrachloride with 100mL anhydrous ethanol evenly, and mix 15g tetrabutyl titanate with 80mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add the mixture consisting of 100mL anhydrous ethanol and 5mL water, stir for 1 hour, and then age at 40℃ for 24 hours to obtain TiO2 / SiO2 sol.

[0032] Step 2: Under stirring conditions, mix 10g of SnCl4 with 50mL of anhydrous ethanol evenly, add it to all the nano TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 150mL of anhydrous ethanol and 30mL of water, stir for 1 hour, and then react at 100℃ for 6 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0033] Step 3: Add water to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water is 1:10. Adjust the concentration of TiO2 / SiO2 / SnO2 nanoparticles to prepare photocatalytic self-cleaning nano-ink.

[0034] The ink is sprayed onto the glass surface, such as... Figure 2 As shown, the contact angle between the formed self-cleaning membrane and water is 2.8°. It should be noted that... Figure 2 The droplet is in a state of being dropped onto the film layer. Due to the small contact angle, the liquid surface is relatively flat. For example... Figure 1 As shown, the average particle size is 17 nm. The photolysis index, measured according to GB / T 30452-2013, is 35.8 nmol / (L·min). After one year of storage, the prepared photocatalytic self-cleaning nano-ink showed that the nanoparticles were stably dispersed in the solvent, exhibiting excellent stability.

[0035] Example 2 A method for preparing a photocatalytic self-cleaning nano-ink includes the following steps: Step 1: Under stirring conditions, mix 20g silicon tetrachloride with 100mL anhydrous ethanol evenly, and mix 15g tetrabutyl titanate with 80mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add the mixture consisting of 100mL anhydrous ethanol and 5mL water, stir for 1 hour, and then age at 40℃ for 24 hours to obtain TiO2 / SiO2 sol.

[0036] Step 2: Under stirring conditions, mix 10g of SnCl4 with 50mL of anhydrous ethanol evenly, add it to all the nano TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 150mL of anhydrous ethanol and 30mL of water, stir for 1 hour, and then react at 100℃ for 6 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0037] Step 3: Add water to the TiO2 / SiO2 / SnO2 nanoparticle solution, with a volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water of 1:5, and adjust the concentration of TiO2 / SiO2 / SnO2 nanoparticles to prepare photocatalytic self-cleaning nano-ink.

[0038] When the ink is sprayed onto a glass surface, the resulting self-cleaning film has a contact angle of 2.5° with water, an average particle size of 17 nm, and a photolysis index of 36.9 nmol / (L・min).

[0039] Example 3 A method for preparing a photocatalytic self-cleaning nano-ink includes the following steps: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0040] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0041] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1. Adjust the concentration of the above-mentioned TiO2 / SiO2 / SnO2 nanoparticles to prepare photocatalytic self-cleaning nano-ink.

[0042] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.3° with water, an average particle size of 15 nm, and a photolysis index of 44.2 nmol / (L・min), which significantly reduces glass fogging.

[0043] Example 4 Compared to Example 3, the aging temperature in step 1 is 20°C, and includes the following steps: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 20℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0044] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0045] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0046] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.1° with water, an average particle size of 13 nm, and a photolysis index of 42.6 nmol / (L・min).

[0047] Example 5 Compared to Example 3, the aging temperature in step 1 is 70°C, and includes the following steps: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 70℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0048] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0049] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0050] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.5° with water, an average particle size of 18 nm, and a photolysis index of 40.5 nmol / (L・min).

[0051] Example 6 Compared to Example 3, step 2 involves a reaction temperature of 90°C and includes the following steps: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0052] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 90℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0053] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0054] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.6° with water, an average particle size of 14 nm, and a photolysis index of 42.4 nmol / (L・min).

[0055] Example 7 Compared to Example 3, step 2 has a reaction temperature of 120°C and includes the following steps: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0056] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 120℃ for 4 hours to obtain TiO2 / SiO2 / SnO2 nanoparticle solution.

[0057] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0058] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.4° with water, an average particle size of 17 nm, and a photolysis index of 43.7 nmol / (L・min).

[0059] Example 8 Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0060] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain TiO2 / SiO2 / SnO2 nanoparticle solution.

[0061] Step 3: Add 300 mL of water and 300 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:3:3, thus preparing a photocatalytic self-cleaning nano-ink.

[0062] When this ink is applied to the glass surface of a photovoltaic module, the self-cleaning film has a contact angle of 2.2° with water, an average particle size of 15 nm, and a photolysis index of 43.1 nmol / (L・min).

[0063] Example 9 Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0064] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0065] Step 3: Add 800 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:8:1 to prepare photocatalytic self-cleaning nano-ink.

[0066] When this ink was applied to the glass surface of a photovoltaic module, the self-cleaning film had a contact angle of 2.2° with water, an average particle size of 15 nm, and a photolysis index of 42.5 nmol / (L・min) measured according to GB / T 30452-2013.

[0067] Comparative Example 1 Compared to Example 3, in step 1, the amount of water added is increased. The specific steps are as follows:

[0068] Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 50mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0069] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain TiO2 / SiO2 / SnO2 nanoparticle solution.

[0070] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0071] Compared with Example 3, the water content in step 1 was increased by 5 times. The high water content led to the rapid hydrolysis of tetrabutyl titanate, and the titanium ion agglomeration formed particles increased from 15 nm to 25 nm. The contact angle was 4.8°, which was significantly increased. The photolysis index was 30.8 nmol / (L・min), the photocatalytic efficiency decreased, and it could not effectively block the precipitation of glass sodium calcium. This proves that the regulation of hydrolysis rate is the core of nanoparticle dispersibility and self-cleaning performance.

[0072] Comparative Example 2 The specific steps for using a single TiO2 material are as follows: Step 1: Under stirring conditions, mix 20g tetrabutyl titanate with 220mL anhydrous ethanol until homogeneous, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain the intermediate product sol.

[0073] Step 2: Under stirring conditions, a mixture of 260 mL anhydrous ethanol and 40 mL water is slowly added to the intermediate product sol obtained in Step 1. The mixture is stirred for 1 hour and then reacted at 110 °C for 4 hours to obtain TiO2 sol.

[0074] Step 3: Add a mixture of 600 mL water and 100 mL anhydrous ethanol to the TiO2 sol. The volume ratio of TiO2 sol to water to ethanol is 1:6:1 to prepare TiO2 ink.

[0075] Lacking the support of the SiO2 framework and the heterojunction effect of SnO2, the contact angle of pure TiO2 particles increased to 5.5°, the hydrophilicity decreased, the photolysis index was 22.9 nmol / (L・min), the photocatalytic efficiency decreased, and the average particle size was 20 nm, proving that the composite structure is the key to multifunctional synergy.

[0076] Comparative Example 3 Compared with Example 3, the aging time in step 1 is 48 hours.

[0077] Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 48 hours to obtain TiO2 / SiO2 sol.

[0078] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 110℃ for 4 hours to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution.

[0079] Step 3: Add 600 mL of water and 100 mL of ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0080] When this ink was applied to the glass surface of a photovoltaic module, the self-cleaning film had a water contact angle of 5.1° and an average particle size of 30 nm. With prolonged aging, larger particles engulfed smaller ones, increasing the average particle size. The photolysis index was 27.1 nmol / (L・min).

[0081] Comparative Example 4 Compared to Example 3, the reaction temperature in step 2 is 250°C.

[0082] The specific steps are as follows: Step 1: Under stirring conditions, mix 25g silicon tetrachloride with 120mL anhydrous ethanol evenly, and mix 20g tetrabutyl titanate with 100mL anhydrous ethanol evenly. Then mix the two together. Under stirring conditions, slowly add a mixture of 250mL anhydrous ethanol and 10mL water, stir for 1 hour, and then age at 50℃ for 12 hours to obtain TiO2 / SiO2 sol.

[0083] Step 2: Under stirring conditions, mix 12g of SnCl4 with 60mL of anhydrous ethanol evenly, add it to all the TiO2 / SiO2 sol prepared in Step 1 above, slowly add a mixture of 200mL of anhydrous ethanol and 40mL of water, stir for 1 hour, and then react at 250℃ for 4 hours to obtain TiO2 / SiO2 / SnO2 nanoparticle solution.

[0084] Step 3: Add 600 mL of water and 100 mL of anhydrous ethanol to the TiO2 / SiO2 / SnO2 nanoparticle solution. The volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water to ethanol is 1:6:1 to prepare photocatalytic self-cleaning nano-ink.

[0085] Compared with Example 3, the side reaction was carried out at a high temperature of 250°C. Under high temperature, the TiO2 crystal form partially transformed into the low-activity rutile phase, the photolysis index was 19.8 nmol / (L・min), the photolysis efficiency decreased significantly, the energy consumption increased, and the high temperature led to increased film brittleness and decreased adhesion. The average particle size further increased to 28 nm, and the contact angle was 5.3°. This proves that the mild reaction temperature of 90°C to 120°C is the key to crystal form optimization and energy saving.

[0086] The material performance data of the above-mentioned embodiments and comparative examples vary with various factors, as shown in Table 1.

[0087] Table 1. Variation of material performance parameters with various factors Comparative Example 1 focuses on the hydrolysis rate regulation mechanism: by disrupting the water / ethanol ratio, the decisive influence of the titanium ion condensation pathway on particle size and performance was verified. Comparative Example 2 verifies the necessity of the composite structure: a single component cannot achieve the synergistic effect of superhydrophilicity, photocatalysis, and antistatic properties. Comparative Example 3 verifies the influence of the aging process on the particle size of the material. Comparative Example 4 highlights the process innovation: mild conditions break through the traditional high-temperature limitations, balancing performance and energy consumption optimization. Analysis of the data in Table 1 shows that increasing the amount of water used in the hydrolysis process increases the hydrolysis rate, leading to particle agglomeration and increased particle size. Increasing the aging temperature and extending the aging time both tend to increase the particle size. Moderate high-temperature conditions accelerate the hydrolysis-condensation reaction rate, promote the in-situ growth and recombination of SnO2, and are conducive to the formation of highly active anatase TiO2, which is beneficial to improving photocatalytic performance. However, excessively high temperatures may cause a transformation of TiO2 crystal form, changing from anatase to rutile, affecting photocatalytic activity. Therefore, this invention effectively controls the particle size of the material by regulating the titanium ion polycondensation path through hydrolysis rate, and obtains a self-cleaning nano-ink with excellent photocatalytic performance.

[0088] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a photocatalytic self-cleaning nano-ink, characterized in that, Includes the following steps: A first mixture of silicon tetrachloride and tetrabutyl titanate was prepared using ethanol as a solvent. A first mixture of ethanol and water was added to the first mixture, and the mixture was stirred to regulate the hydrolysis process of tetrabutyl titanate. Then, the mixture was aged. Tetrabutyl titanate formed TiO2 through a hydrolysis-condensation reaction, and SiO2 coated the surface of the TiO2, thus obtaining a TiO2 / SiO2 sol. The volume ratio of ethanol in the first mixture to ethanol in the first mixture to water in the first mixture was 22~36:20~25:

1. The aging temperature was 20℃~70℃, and the aging time was 12h~24h. An ethanol solution of SnCl4 was added to TiO2 / SiO2 sol to prepare a second mixture. A second mixture of ethanol and water was added to the second mixture, and the mixture was stirred. The mixture was then reacted at 90℃~120℃. SnO2 grew in situ and coated the SiO2 surface to obtain a TiO2 / SiO2 / SnO2 nanoparticle solution. A diluent was added to a TiO2 / SiO2 / SnO2 nanoparticle solution to adjust the concentration of TiO2 / SiO2 / SnO2 nanoparticles, thus preparing a photocatalytic self-cleaning nano-ink.

2. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, In the first mixture, the ratio of silicon tetrachloride to ethanol is 1g:8.8mL~9mL; the ratio of tetrabutyl titanate to ethanol is 1g:11mL~12mL.

3. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, The mass ratio of tetrabutyl titanate to SnCl4 is 15~20:10~12; in the ethanol solution of SnCl4, the ratio of SnCl4 to ethanol is 1g:5mL.

4. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, In the second mixture, the volume ratio of ethanol to water is 5:1, and the volume ratio of SnCl4 to the second mixture is 1g:18mL~20mL.

5. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, In the step of preparing TiO2 / SiO2 sol, the stirring time is 1 hour.

6. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, In the step of preparing TiO2 / SiO2 / SnO2 nanoparticle solution, the stirring time is 1 hour and the reaction time is 4 to 6 hours.

7. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, The diluent is water, and the volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution to water is 1:5~10.

8. The method for preparing photocatalytic self-cleaning nano-ink according to claim 1, characterized in that, The diluent is a third mixture of water and ethanol; the volume ratio of TiO2 / SiO2 / SnO2 nanoparticle solution: water in the third mixture: ethanol in the third mixture is 1:3~8:1~3.

9. A photocatalytic self-cleaning nano-ink, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. The photocatalytic self-cleaning nano-ink according to claim 9, characterized in that, The photocatalytic self-cleaning nano-ink consists of a solvent and nanoparticles uniformly dispersed in the solvent. The nanoparticles have a core-shell structure and consist of TiO2, SiO2, and SnO2 from the inside out. The average particle size of the nanoparticles is 10 nm to 20 nm.

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