Method for manufacturing a core-shell hollow structure in which photocatalytic particles self-drive to generate a core.

Abstract

A method for producing a core-shell hollow structure in which photocatalytic particles are self-driven to generate cores is disclosed. The method includes the steps of: (1) mixing an alcohol solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, the first solution containing modified titanium dioxide nanospheres; (2) injecting air into water by a micro-nano bubble generator, shearing and crushing to obtain a second solution, the second solution containing micro-nano bubbles; (3) mixing the second solution with the first solution under a temperature of 35 degrees Celsius or higher to obtain a third solution; (4) adding ammonia water and tetraethyl orthosilicate solution to the third solution to obtain a fourth solution; and (5) separating, drying the precipitate, and then calcining to obtain core-shell hollow structure nanoparticles. The obtained core-shell hollow structure expands the active surface of the catalytic reaction, improves activity, and is easy to mass-produce industrially due to its simple method.

Description

Technical Field

[0001] The present disclosure relates to the field of polymer materials, and specifically to a method for manufacturing a core-shell hollow structure in which photocatalytic particles self-drive to generate a core.

Background Art

[0002] Titanium dioxide is a commonly seen semiconductor photocatalytic material. Under light irradiation, titanium dioxide can convert light energy into chemical energy and decompose toxic and harmful organic substances within a relatively short time. In addition, titanium dioxide also has characteristics such as high stability, light corrosion resistance, and non-toxicity, and does not cause secondary pollution during the treatment process. Therefore, it has attracted more and more attention in fields such as antibacterial, deodorization, oil stain decomposition, mold and algae prevention, and air purification. However, since the catalytic reaction is essentially a surface contact reaction, it occurs only on the surface of the material. Therefore, in the case of a catalyst, not only is the limited surface area used for the catalytic reaction, but it should also be responsible for the task of particle loading and fixation, which often greatly affects the catalytic effect.

[0003] The core-shell structure is a nanoscale ordered assembly structure formed by wrapping one kind of nanomaterial with another kind of nanomaterial by chemical bonds or other acting forces. The core-shell structure plays an important role in maintaining the functional stability of the catalyst, adjusting the physical and chemical properties of the material to achieve complementary advantages, preventing the aggregation of nanoparticles, and controlling the particle interface reaction, and also has broad prospects for applications in photocatalysis, batteries, gas storage and separation. However, for nanocatalytic materials that promote reactions depending on the surface area, how to solve the problem that the core surface is covered by the shell and causes interference to the catalytic activity of the core is always an unavoidable obstacle on the path of nanocatalytic application.

Summary of the Invention

[0004] This disclosure aims to solve, at least to some extent, one of the technical problems of the related technology. This disclosure utilizes the surface-interface principle that surface-hydrophobic materials are hydrophilic, and modifies commercially available titanium dioxide nanosphere particles with surface hydrophobicity using tetraoctadecyl orthotitanate. Subsequently, the titanium dioxide particles are placed in a system of water and micro-nanobubbles, and the difference in tension between the hydrophilic and hydrophobic surfaces causes the titanium dioxide particles to self-drive into the micro-nanobubbles. Finally, by synthesizing a silicon dioxide shell at the water-air interface of the micro-nanobubbles, photocatalytic core-shell hollow structure nanoparticles having a hollow structure between the core and the shell are obtained.

[0005] Specifically, this disclosure provides the following technical solutions.

[0006] A first aspect of this disclosure provides a method for producing core-shell hollow structure nanoparticles. The method is (1) A step of mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, wherein the first solution contains modified titanium dioxide nanospheres, (2) A step of injecting air into water using a micro-nanobubble generator, shearing and crushing it to obtain a second solution, wherein the second solution contains micro-nanobubbles, (3) The step of mixing the second solution and the first solution under conditions of a temperature of 35 degrees Celsius or higher to obtain a third solution, (4) Adding aqueous ammonia and tetraethyl orthosilicate solution to the third solution to obtain a fourth solution, (5) The process includes the step of separating the precipitate, drying it, and then calcining it to obtain core-shell hollow structure nanoparticles.

[0007] According to the embodiments of this disclosure, the method for producing the above-described core-shell hollow structure nanoparticles may further include the following technical features.

[0008] Furthermore, in step (1), the alcoholic solution of titanium dioxide contains 1 to 4 parts by weight of titanium dioxide, and the amount of tetraoctadecyl orthotitanate is 0.1 to 1.5 parts by weight.

[0009] Furthermore, in step (1), the diameter of the titanium dioxide in the alcohol solution of titanium dioxide is 200 to 400 nanometers.

[0010] Furthermore, in step (1), the titanium dioxide alcohol solution is an ethanol solution of titanium dioxide containing 1 to 4 parts by weight of titanium dioxide and 10 to 50 parts by weight of anhydrous ethanol.

[0011] Furthermore, in step (2), the diameter of the micro-nanobubbles is 600 to 1000 nanometers.

[0012] Furthermore, the shearing and crushing time is 4 to 9 hours.

[0013] Furthermore, in step (2), air is injected into the water using a micro-nanobubble generator. According to a preferred embodiment of the present disclosure, air is injected into the water using a micro-nanobubble generator so that the air humidity is between 5% and 30%.

[0014] Furthermore, in step (3), the temperature is 40 degrees Celsius.

[0015] Furthermore, in step (4), the amount of titanium dioxide in step (1) is calculated to be 1 to 4 parts by weight, the amount of aqueous ammonia is 1 to 10 parts by weight, and the amount of tetraethyl orthosilicate solution is 2 to 10 parts by weight.

[0016] Furthermore, in step (5), the baking temperature is 400 to 500 degrees Celsius, and the baking time is 1 to 3 hours.

[0017] Furthermore, the drying temperature is 70 to 90 degrees Celsius.

[0018] A second aspect of this disclosure provides a method for producing core-shell hollow structure nanoparticles. The method is as follows: (1) A step of mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, wherein the first solution contains modified titanium dioxide nanospheres, and the alcoholic solution of titanium dioxide contains 10 to 50 parts by weight of anhydrous ethanol and 1 to 4 parts by weight of titanium dioxide. (2) A step of injecting air into water using a micro-nanobubble generator, shearing and crushing it to obtain a second solution, wherein the second solution contains micro-nanobubbles, and the diameter of the micro-nanobubbles is 600-1000 nm. (3) The step of mixing the second solution and the first solution under conditions of 40 degrees Celsius to obtain the third solution, (4) Adding 1 to 10 parts by weight of aqueous ammonia and 2 to 10 parts by weight of tetraethyl orthosilicate solution to the third solution to obtain a fourth solution, (5) The process includes the step of separating the precipitate, drying it, and then calcining it to obtain core-shell hollow structure nanoparticles.

[0019] A third aspect of this disclosure provides core-shell hollow structure nanoparticles manufactured by the method of either the first or second aspect.

[0020] The beneficial effects of this disclosure are as follows: The method provided by this disclosure yields core-shell hollow nanoparticles, the resulting core-shell hollow structure broadens the active surface of the catalytic reaction, improves activity, and saves raw materials. The manufacturing process of the product is relatively simple, the conditions are easy to control, and it is easy to mass-produce industrially. [Brief explanation of the drawing]

[0021] [Figure 1] This is an electron microscope image of a core-shell hollow structure nanoparticle according to an embodiment of the present disclosure.

[0022] [Figure 2] EDS energy-dispersive spectrogram of core-shell hollow-structured nanoparticles according to an embodiment of the present disclosure.

[0023] [Figure 3] XRD data results of core-shell hollow-structured nanoparticles according to an embodiment of the present disclosure.

[0024] [Figure 4] Photocatalytic decolorization experiment results of rhodamine B solution according to an embodiment of the present disclosure.

[0025] [Figure 5] Antibacterial performance test results of Escherichia coli and Staphylococcus aureus according to an embodiment of the present disclosure.

[0026] [Figure 6] Electron microscope result diagram according to Comparative Example 1 of the present disclosure.

[0027] [Figure 7] Electron microscope result diagram according to Comparative Example 2 of the present disclosure.

[0028] [Figure 8] Electron microscope result diagram according to Comparative Example 3 of the present disclosure.

Mode for Carrying Out the Invention

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, the disclosed embodiments are exemplary for interpreting the present disclosure and should not be construed as limitations on the present disclosure.

[0030] Micro- and nanobubbles are special gaseous states that exist at the interface between gases and liquids. They can exist stably in liquids for extended periods and can be used as non-contact manufacturing templates for catalyst surfaces. Micro- and nanobubbles can be obtained using commercially available micro- and nanobubble generators. For example, commercially available micro- and nanobubble generators are high-shear generators, but typically, micro- and nanobubbles are obtained by crushing large gas-liquid mixed bubbles using dynamic or static high-speed shear equipment.

[0031] This disclosure utilizes the surface-interface principle that hydrophobic materials are hydrophilic, modifying the surface with hydrophobic titanium dioxide particles and placing them in a system of water and micro-nanobubbles. Due to the difference in surface tension between hydrophilic and hydrophobic surfaces, the titanium dioxide particles are allowed to self-drive into the micro-nanobubbles. Finally, by synthesizing a silicon dioxide shell at the water-air interface of the micro-nanobubbles, a photocatalytic core-shell hollow structure nanoparticle having a hollow structure between the core and the shell is obtained.

[0032] This disclosure provides a method for producing core-shell hollow structure nanoparticles. The method is as follows: (1) A step of mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, wherein the first solution contains modified titanium dioxide nanospheres, (2) A step of injecting air into water using a micro-nanobubble generator, shearing and crushing it to obtain a second solution, wherein the second solution contains micro-nanobubbles, (3) The step of mixing the second solution and the first solution under conditions of a temperature of 35 degrees Celsius or higher to obtain a third solution, (4) Adding aqueous ammonia and tetraethyl orthosilicate solution to the third solution to obtain a fourth solution, (5) The process includes the step of separating the precipitate, drying it, and then calcining it to obtain core-shell hollow structure nanoparticles.

[0033] There are no special requirements regarding the manufacturing sequence of steps (1) and (2).

[0034] According to a specific embodiment, in step (1), the titanium dioxide alcohol solution contains 1 to 4 parts by weight of titanium dioxide, and the tetraoctadecyl orthotitanate is 0.1 to 1.5 parts by weight. An appropriate amount of tetraoctadecyl orthotitanate can play a role in surface hydrophobic modification, and thus modified titanium dioxide nanospheres can be obtained.

[0035] In a specific embodiment, in step (1), the diameter of the titanium dioxide in the titanium dioxide alcohol solution is 200 to 400 nanometers.

[0036] In a specific embodiment, in step (1), the titanium dioxide alcohol solution is an ethanol solution of titanium dioxide containing 1 to 4 parts by weight of titanium dioxide and 10 to 50 parts by weight of anhydrous ethanol.

[0037] In a specific embodiment, in step (2), the diameter of the micro-nanobubbles is 600 to 1000 nanometers, for example, 700 to 1000 nanometers, 800 to 1000 nanometers, 900 to 1000 nanometers, or 600 to 800 nanometers. The diameter of the micro-nanobubbles directly affects to some extent the performance of the core-shell hollow structure nanoparticles finally produced and the size of the space between the core and shell formed. If the diameter of the micro-nanobubbles is too small, it affects the loading of the core-shell hollow structure nanoparticles, and if the diameter of the micro-nanobubbles is too large, the shell layer structure of the core-shell hollow structure nanoparticles finally formed becomes unstable.

[0038] According to specific embodiments of this disclosure, the shearing and crushing time is 4 to 9 hours.

[0039] According to a specific embodiment of the present disclosure, in step (2), air is injected into the water by a micro-nanobubble generator.

[0040] According to a specific embodiment of the present disclosure, in step (3), the temperature is 40 degrees Celsius. As the alcohol evaporates, the surface-hydrophobic modified titanium dioxide nanospheres acquire both hydrophobic and hydrophilic properties due to the action of surface tension, and then self-propelled into the interior of the bubbles (similar to the process of bubble removal in a liquid).

[0041] Tetraethyl orthosilicate can form silicon dioxide under the action of aqueous ammonia. According to a specific embodiment of the present disclosure, in step (4), the amount of titanium dioxide in step (1) is calculated to be 1 to 4 parts by weight, the amount of aqueous ammonia is 1 to 10 parts by weight, and the amount of tetraethyl orthosilicate solution is 2 to 10 parts by weight.

[0042] According to a specific embodiment of the present disclosure, in step (5), the baking temperature is 400 to 500 degrees Celsius, and the baking time is 1 to 3 hours.

[0043] According to specific embodiments of this disclosure, the drying temperature is 70 to 90 degrees Celsius.

[0044] The present disclosure is described in more detail below, along with the examples. The examples are for illustrative purposes only and do not limit the scope of the present disclosure. The solutions of the present disclosure are interpreted below in conjunction with the examples. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered to limit the scope of the present disclosure. Unless specific techniques or conditions are specified in the examples, they shall be carried out in accordance with the techniques or conditions described in the literature in the art or in accordance with product specifications. Unless the manufacturer is specified, the reagents and equipment used are all conventional products that can be purchased on the market.

[0045] Example 1 Example 1 provides a method for producing core-shell hollow structure nanoparticles. The method includes the following steps.

[0046] 1. Add 2 parts by weight of commercially available titanium dioxide nanospheres with a diameter of approximately 200-400 nm to 1.30 parts by weight of anhydrous ethanol and stir uniformly.

[0047] 2. Add 1 part by weight of tetraoctadecyl orthotitanate to the solution obtained in step 1 above, and stir for 24 hours to perform surface hydrophobic modification of titanium dioxide nanospheres.

[0048] 3. Micro-nanobubbles are obtained by injecting air into 100 parts by weight of distilled water using a commercially available micro-nanobubble generator, and then shearing and crushing the gas-liquid mixture. The diameter of the micro-nanobubbles is controlled to approximately 800 nm, and the shearing time is 6 hours.

[0049] 4. After heating the solution obtained in step 3 to 40 degrees Celsius, quickly add 10 parts by weight of the solution obtained in step 2.

[0050] Add 5.5 parts by weight of aqueous ammonia to the solution obtained in step 4, stir vigorously, then add 5 parts by weight of tetraethyl orthosilicate solution dropwise and stir for 4 hours.

[0051] 6. Finally, the solution obtained in step 5 is centrifuged to obtain a precipitate, which is then dried at 80 degrees Celsius for 12 hours. After that, the precipitate is calcined at 400-500 degrees Celsius for 1-3 hours to obtain core-shell hollow structure nanoparticles.

[0052] The electron microscope images of the obtained core-shell hollow structure nanoparticles are shown in Figure 1.

[0053] The fabricated core-shell hollow structure nanoparticles were characterized by EDS energy-dispersive spectroscopy, and the results are shown in Figure 2. The EDS energy-dispersive spectroscopy in Figure 2 shows the proportion of core-shell hollow structure nanoparticles as each element of the photocatalyst composition.

[0054] Furthermore, as shown in Figure 3, the XRD data indicates that the lattice structure of titanium dioxide particles in the core-shell hollow nanoparticles remains unchanged, and the data shows the standard lattice structure parameters of anatase-phase titanium dioxide.

[0055] The results of the photocatalytic fading experiment of the rhodamine B solution are shown in Figure 4. This result shows that core-shell hollow structure nanoparticles faded 1 × 10⁶ times within 1 hour. -5 This study demonstrates that a mol / L rhodamine B (RhB) solution can photocatalyze color fading, and that its catalytic activity is higher than that of untreated titanium dioxide particles under the same conditions.

[0056] The antimicrobial test results for Escherichia coli and Staphylococcus aureus are shown in Figure 5. These results also show that the sample with core-shell hollow nanoparticles added (numbers 5 and 6 in Figure 5, b) exhibits the highest antimicrobial performance when compared with the blank sample without additives (numbers 1 and 2 in Figure 5, b) and the titanium dioxide sample with additives (numbers 3 and 4 in Figure 5, b).

[0057] Example 2 Example 2 provides a method for producing core-shell hollow structure nanoparticles. The method includes the following steps.

[0058] Add 4 parts by weight of commercially available titanium dioxide nanospheres with a diameter of approximately 200-400 nm to 1.50 parts by weight of anhydrous ethanol and stir uniformly.

[0059] 2. Add 1.5 parts by weight of tetraoctadecyl orthotitanate to the solution obtained above and stir for 40 hours to perform surface hydrophobic modification of titanium dioxide nanospheres.

[0060] 3. Micro-nanobubbles are obtained by injecting air into 100 parts by weight of distilled water using a commercially available micro-nanobubble generator, and then shearing and crushing the gas-liquid mixture. The diameter of the micro-nanobubbles is controlled to approximately 1000 nm, and the shearing time is 8 hours.

[0061] 4. After heating the solution obtained in step 3 to 40 degrees Celsius, quickly add 20 parts by weight of the solution obtained in step 2.

[0062] 5. Add 10 parts by weight of aqueous ammonia to the solution described in step 4, stir vigorously, then add 10 parts by weight of tetraethyl orthosilicate solution dropwise and stir for 4 hours.

[0063] 6. Finally, the solution obtained in step 5 is centrifuged to obtain a precipitate, which is then dried at 80 degrees Celsius for 12 hours. After that, the precipitate is calcined at 400-500 degrees Celsius for 1-3 hours to obtain core-shell hollow structure nanoparticles.

[0064] The core-shell hollow structure nanoparticles produced in Example 2 were subjected to the same characterization as in Example 1, and the results showed that they exhibited similar characteristics to the core-shell hollow structure nanoparticles produced in Example 1.

[0065] Comparative Example 1 During the experiment, as shown in Figure 6, when hydrophobic modification was performed on the surface of titanium dioxide nanospheres, it was found that if tetraoctadecyl orthotitanate was not used, the surface hydrophobicity was insufficient. This prevented the formation of the hydrophobic and hydrophilic properties provided by the surface tension of this disclosure, which allows for self-driven entry into the bubble interior. As a result, the silicon dioxide shells that were ultimately formed lacked a core. Similarly, insufficient amounts of tetraoctadecyl orthotitanate also affected the structure and performance of the formed core-shell hollow nanoparticles.

[0066] Comparative Example 2 During the study, as shown in Figure 7, it was discovered that when tetraethyl orthosilicate is reacted with aqueous ammonia to synthesize a silicon dioxide shell at the water-air interface, the silicon dioxide reaction occurs too quickly, preventing the formation of the shell structure. Therefore, when adding the tetraethyl orthosilicate solution, it should be added dropwise.

[0067] Comparative Example 3 During the research, as shown in Figure 8, it was discovered that when too much tetraethyl orthosilicate solution is added during the process in which tetraethyl orthosilicate synthesizes a silicon dioxide shell at the water-air interface through the action of ammonia water, an excess of silicon dioxide is created in the system, leading to a phenomenon of silicon dioxide self-aggregation and affecting the formation of a normal shell structure.

[0068] It should be noted that the above description is merely a preferred embodiment of the present disclosure, and those skilled in the art can make several further improvements and embellishments without departing from the principles of the present disclosure, and these improvements and embellishments should also be considered within the scope of the present disclosure.

Claims

1. A method for producing core-shell hollow structure nanoparticles, (1) A step of mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, wherein the first solution contains modified titanium dioxide nanospheres, (2) A step of injecting air into water using a micro-nanobubble generator, shearing and crushing it to obtain a second solution, wherein the second solution contains micro-nanobubbles, and the diameter of the micro-nanobubbles is 600 to 1000 nanometers. (3) The step of mixing the second solution and the first solution under conditions of a temperature of 35 degrees Celsius or higher to obtain a third solution, (4) Adding aqueous ammonia and tetraethyl orthosilicate solution to the third solution to obtain a fourth solution, (5) Separation, drying of the precipitate, and calcination to obtain core-shell hollow structure nanoparticles. A method characterized by including the following.

2. In step (1), the titanium dioxide alcohol solution contains 1 to 4 parts by weight of titanium dioxide, and the tetraoctadecyl orthotitanate is 0.1 to 1.5 parts by weight. The method according to claim 1, characterized in that, optionally, in step (1), the diameter of the titanium dioxide in the alcohol solution of titanium dioxide is 200 to 400 nanometers.

3. The method according to claim 1, characterized in that, in step (1), the alcohol solution of titanium dioxide is an ethanol solution of titanium dioxide comprising 1 to 4 parts by weight of titanium dioxide and 10 to 50 parts by weight of anhydrous ethanol.

4. The method according to claim 1, characterized in that, in step (2), the shearing and crushing time is 4 to 9 hours.

5. The method according to claim 1, characterized in that in step (2), air is injected into the water using a micro-nanobubble generator so that the air humidity is between 5% and 30%.

6. The method according to claim 1, characterized in that in step (3), the temperature is 40 to 50 degrees Celsius.

7. The method according to claim 1, characterized in that, in step (4), the amount of titanium dioxide in step (1) is calculated to be 1 to 4 parts by weight, the amount of aqueous ammonia is 1 to 10 parts by weight, and the amount of tetraethyl orthosilicate solution is 2 to 10 parts by weight.

8. In step (5), the baking temperature is 400 to 500 degrees Celsius, and the baking time is 1 to 3 hours. The method according to claim 1, characterized in that the drying temperature is optionally 70 to 90 degrees Celsius.

9. A method for producing core-shell hollow structure nanoparticles, (1) A step of mixing an alcoholic solution of titanium dioxide with tetraoctadecyl orthotitanate to obtain a first solution, wherein the first solution contains modified titanium dioxide nanospheres, and the alcoholic solution of titanium dioxide contains 10 to 50 parts by weight of anhydrous ethanol and 1 to 4 parts by weight of titanium dioxide. (2) A step of injecting air into water using a micro-nanobubble generator, shearing and crushing it to obtain a second solution, wherein the second solution contains micro-nanobubbles, and the diameter of the micro-nanobubbles is 600 to 1000 nm. (3) The step of mixing the second solution and the first solution under conditions of 40 degrees Celsius to obtain a third solution, (4) Adding 1 to 10 parts by weight of aqueous ammonia and 2 to 10 parts by weight of tetraethyl orthosilicate solution to the third solution to obtain a fourth solution, (5) Separation, drying of the precipitate, and calcination to obtain core-shell hollow structure nanoparticles. A method characterized by including the following.

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