Method for preparing two-dimensional titanium dioxide microwire by using high viscosity system and application thereof

Abstract

The application provides a method for preparing two-dimensional titanium dioxide microwires by using a high-viscosity system and application. The method comprises the following steps: providing a high-viscosity system, wherein the high-viscosity system is an aqueous solution of guar gum hydroxypropyltrimethyl ammonium chloride; and performing high-speed shearing treatment on the high-viscosity system; adding liquid tetrabutyl titanate into the high-viscosity system, stirring, centrifugal drying, and obtaining the two-dimensional titanium dioxide microwires. The preparation method is simple, reaction conditions are normal temperature and normal pressure, the method is easy to control, mass production is realized, and the prepared two-dimensional titanium dioxide microwires have good catalytic activity.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic nanomaterials, specifically to a method and application for preparing two-dimensional titanium dioxide microwires using a high-viscosity system. Background Technology

[0002] Titanium dioxide is a common semiconductor photocatalyst material. Under light irradiation, it can convert light energy into chemical energy, successfully decomposing most organic compounds, including recalcitrant organic compounds, in a short time. Titanium dioxide as a photocatalyst has several advantages: 1. It converts solar energy into chemical energy for utilization. 2. It has a fast degradation rate; the ·OH radicals generated by photoexcitation holes are strong oxidizing free radicals, which can successfully decompose most organic compounds, including recalcitrant organic compounds, in a short time. 3. It exhibits non-selective degradation, capable of degrading almost any organic pollutant. 4. It possesses high stability, resistance to photocorrosion, and non-toxicity, and does not produce secondary pollution during the treatment process; organic pollutants can be oxidized and degraded into CO2 and H2O, which are non-toxic to humans. Furthermore, its high stability, resistance to photocorrosion, and non-toxicity, along with the absence of secondary pollution during treatment, have made it increasingly popular in fields such as antibacterial, deodorization, oil decomposition, mildew and algae prevention, and air purification.

[0003] Since photocatalytic materials are generally one-dimensional powder materials, their practical application requires consideration of fabricating them into two-dimensional linear materials with micrometer-scale lengths. The advantages of two-dimensional linear materials are as follows: 1. They can maintain their intended catalytic activity; 2. They solve the problems of convenient recycling and use; 3. They avoid the biosafety risks associated with nanomaterials.

[0004] The preparation of micron-scale two-dimensional linear materials generally involves the following approaches: 1. Nanoparticle self-assembly into wires. This method, due to the lack of selectivity of the particles themselves, often yields bulk materials, requiring external force to form wires. 2. Catalyst loading onto fiber supports. There are generally two methods: one is loading onto the fiber surface, which has the advantages of low dosage and large effective area, but the disadvantages are complex processes and easy detachment; the second is mixing the catalyst into the raw material for fiber fabrication, which has the advantages of simple processes and less detachment, but the disadvantages are high dosage, small effective area, and the catalyst's active surface being largely obscured by the support material, resulting in poor activity.

[0005] Further improvements are needed to obtain two-dimensional titanium dioxide microwires. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. This invention provides a method for preparing two-dimensional titanium dioxide microwires using a high-viscosity system and its application. By preparing a high-viscosity reaction system and, under high-speed shear, evolving the classic process of hydrolyzing tetrabutyl titanate to prepare one-dimensional titanium dioxide nanospheres into micron-sized two-dimensional titanium dioxide wire materials, two-dimensional titanium dioxide microwires can be obtained. This preparation method is simple, can be mass-produced, and is beneficial for industrial production and application. The obtained two-dimensional titanium dioxide microwires not only retain their expected catalytic activity but are also easy to recycle and reuse, showing good prospects for practical applications.

[0007] Specifically, the present invention provides the following technical solution:

[0008] A first aspect of the present invention provides a method for preparing two-dimensional titanium dioxide microwires using a high-viscosity system, comprising:

[0009] A high-viscosity system is provided, wherein the high-viscosity system is an aqueous solution of guar hydroxypropyltrimethylammonium chloride, and the high-viscosity system is subjected to high-speed shearing treatment;

[0010] Tetrabutyl titanate was added to the high-viscosity system, stirred, centrifuged and dried to obtain the two-dimensional titanium dioxide microwires.

[0011] In some embodiments of the present invention, the concentration of the aqueous solution of guar hydroxypropyltrimethylammonium chloride is 0.6‰ to 1.2‰ (w / w), and the viscosity of the aqueous solution of guar hydroxypropyltrimethylammonium chloride is 1.7-5.2 Pa·s.

[0012] In some embodiments of the present invention, the high-speed shearing process is performed at a speed of 7000-10000 rpm.

[0013] In some embodiments of the present invention, the volume ratio of the tetrabutyl titanate to the high viscosity system is (1.0-4.5):(50-80).

[0014] In some embodiments of the present invention, the tetrabutyl titanate is added to the high viscosity system at a dropping rate of 0.05-0.10 mL / min.

[0015] In some embodiments of the present invention, the drying temperature is 70 to 100 degrees Celsius.

[0016] A second aspect of the present invention provides a two-dimensional titanium dioxide microwire, which is prepared according to the method described in any embodiment of the first aspect above.

[0017] The third aspect of the present invention provides the use of two-dimensional titanium dioxide microwires in the field of photocatalytic nanomaterials, wherein the two-dimensional titanium dioxide microwires are the same as those described in the second aspect.

[0018] The beneficial effects achieved by this invention are as follows:

[0019] (1) The two-dimensional titanium dioxide microwires provided by the present invention can not only maintain their catalytic activity, but also facilitate recycling and reuse.

[0020] (2) The preparation method is simple, the reaction conditions are at room temperature and pressure, it is easy to control, it can be mass-produced, it is conducive to industrial production and application, and has good practical application prospects. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of two-dimensional titanium dioxide micrometer wires provided according to an embodiment of the present invention.

[0022] Figure 2 This is a scanning electron microscope image of two-dimensional titanium dioxide micrometer wires provided according to an embodiment of the present invention.

[0023] Figure 3 These are scanning electron microscope images of titanium dioxide nanoparticle products prepared using different types of thickeners.

[0024] Figure 4 These are scanning electron microscope images of titanium dioxide nanoparticle products prepared using different thickeners.

[0025] Figure 5 These are scanning electron microscope images of titanium dioxide nanoparticle products prepared using different thickeners. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0027] This invention provides a method for preparing two-dimensional titanium dioxide microwires using a high-viscosity system, comprising:

[0028] A high-viscosity system is provided, wherein the high-viscosity system is an aqueous solution of guar hydroxypropyltrimethylammonium chloride, and the high-viscosity system is subjected to high-speed shearing treatment;

[0029] Tetrabutyl titanate was added to the high-viscosity system, stirred, centrifuged and dried to obtain the two-dimensional titanium dioxide microwires.

[0030] The inventors of this application have creatively developed a high-viscosity system using guar hydroxypropyltrimethylammonium chloride, which offers several advantages. First, guar hydroxypropyltrimethylammonium chloride has a very strong binding affinity to water, controlling the hydrolysis process of tetrabutyl titanate and preventing it from hydrolyzing too rapidly. Second, it is immiscible with tetrabutyl titanate, allowing the interface between the two phases to serve as the reaction site. Third, its cationic nature facilitates the adsorption of anionic titanium dioxide particles at the interface. Fourth, the high-viscosity system formed by the aqueous solution of guar hydroxypropyltrimethylammonium chloride can produce a stringing effect under stirring, thereby inducing particles to form threads. During the research process, it was found that other high-viscosity systems did not yield satisfactory results.

[0031] In preparing the high-viscosity system, the inventors also tried various natural polymer thickeners, such as starch, gelatin, sodium alginate, casein, guar gum, chitosan, gum arabic, xanthan gum, soybean protein gum, natural rubber, lanolin, and agar. Among them, cationic guar gum hydroxypropyltrimethylammonium chloride is the most effective and water-soluble natural polymer. It can form a highly viscous solution with water even at low concentrations. During the research, it was found that to prepare two-dimensional titanium dioxide microwires using a high-viscosity system, three essential factors must be met: 1. The thickener must have a sufficiently strong binding force to water to significantly slow down the formation rate of titanium dioxide nanospheres during the hydrolysis of tetrabutyl titanate; otherwise, a chaotic mass of titanium dioxide particles will be uncontrollably generated. 2. The thickener must be cationic to effectively adsorb the negatively charged titanium dioxide nanospheres near the thickener; otherwise, the desired structure cannot be formed. 3. Due to the non-Newtonian rheological properties of cationic guar hydroxypropyltrimethylammonium chloride (apparent viscosity decreases with increasing shear rate), during high-speed shearing, the high-viscosity liquid at the shear center and surrounding areas will exhibit a difference in viscosity due to the non-Newtonian rheological properties, resulting in a low viscosity center and a high viscosity periphery. This viscosity difference leads to thickener stringing. Only by meeting the above three conditions can this structure be obtained. If any condition is not met, only conventional titanium dioxide nanoparticles can be obtained, and this structure cannot be achieved. (See reference...) Figures 3-5 As shown. Among them Figure 3 These are scanning electron microscope images of titanium dioxide nanoparticles obtained using gelatin as a thickener. Figure 4 These are scanning electron microscope images of titanium dioxide nanoparticles obtained using sodium alginate as a thickener. Figure 5This is a scanning electron microscope image of titanium dioxide nanoparticles obtained using guar gum with an unsuitable viscosity as a high-viscosity system. According to a specific embodiment, the concentration of the aqueous solution of guar gum hydroxypropyltrimethylammonium chloride is 0.6‰–1.2‰ (w / w), and the viscosity of the aqueous solution of guar gum hydroxypropyltrimethylammonium chloride is 0.7–5.2 Pa·s. According to a preferred embodiment, the viscosity of the aqueous solution of guar gum hydroxypropyltrimethylammonium chloride is 1.7–5.2 Pa·s. According to a more preferred embodiment, the viscosity of the aqueous solution of guar gum hydroxypropyltrimethylammonium chloride is 2.5–3.5 Pa·s. Studies have found that when the concentration of the aqueous solution of guar gum hydroxypropyltrimethylammonium chloride is too low, the viscosity is not high, and the binding force is weak; when it is too high, the viscosity is too high, the binding force is too strong, and the effect is also not good.

[0032] According to a specific implementation, the high-speed shearing process is performed at a speed of 7000-10000 rpm.

[0033] According to a specific embodiment, the volume ratio of tetrabutyl titanate to the high-viscosity system is (1.0–4.5):(50–80). Studies have found that when the volume of tetrabutyl titanate is too high, the proportion of the high-viscosity system is insufficient, which affects the resulting wire drawing effect and thus the quality of the two-dimensional titanium dioxide microwires. Similarly, when the volume of the high-viscosity system is too high, the viscosity becomes too high, which also affects the quality of the two-dimensional titanium dioxide microwires.

[0034] According to a specific embodiment, the tetrabutyl titanate is added to the high viscosity system at a dropping rate of 0.05-0.10 mL / min.

[0035] According to a specific implementation method, the drying temperature is 70 to 100 degrees Celsius.

[0036] The present invention also provides a two-dimensional titanium dioxide microwire, which is prepared according to the method described above.

[0037] The third aspect of the present invention provides the use of two-dimensional titanium dioxide microwires in the field of photocatalytic nanomaterials, wherein the two-dimensional titanium dioxide microwires are the same as those described in the second aspect.

[0038] The present invention will be described below through specific embodiments. It should be noted that these embodiments are only used to facilitate understanding by those skilled in the art and should not be considered as limiting the scope of protection of the present invention. Unless otherwise specified in the embodiments, all reagents used can be purchased or prepared by oneself.

[0039] Example 1

[0040] Example 1 describes the preparation of two-dimensional titanium dioxide microwires using the following method. The cationic guar hydroxypropyltrimethylammonium chloride used was commercially available.

[0041] (1) Preparation of high-viscosity reaction system:

[0042] Cationic guar hydroxypropyltrimethylammonium chloride was dissolved in deionized water at a concentration of 1‰ (w / w) and a viscosity of 3 Pa·s.

[0043] (2) Preparation of two-dimensional titanium dioxide microwires:

[0044] 1) The above high-viscosity reaction system was subjected to high-speed shearing treatment. The shearing rotor was selected using a bottom suction method (avoiding the top suction method, which would lead to excessive air intake and affect the hydrolysis rate of tetrabutyl titanate). The shearing speed was maintained at 8000 rpm.

[0045] 2) Slowly add 2 mL of tetrabutyl titanate stock solution dropwise to 60 mL of high-viscosity reaction system. The dropping rate is 0.08 mL / min. After the addition is complete, seal and stir for 5 hours.

[0046] 3) After stirring, centrifuge and dry at 80 degrees Celsius for 12 hours to obtain the product.

[0047] Example 2

[0048] Example 2: Two-dimensional titanium dioxide microwires were prepared by the following method.

[0049] (1) Preparation of high-viscosity reaction system:

[0050] Cationic guar hydroxypropyltrimethylammonium chloride was dissolved in deionized water at a concentration of 0.8‰ (w / w), and the viscosity was controlled at around 2.5 Pa·s.

[0051] (2) Preparation of two-dimensional titanium dioxide microwires:

[0052] 1) The above high-viscosity reaction system was subjected to high-speed shearing treatment. The shearing rotor was selected using a bottom suction method (avoiding the top suction method, which would lead to excessive air intake and affect the hydrolysis rate of tetrabutyl titanate). The shearing speed was maintained at 8000 rpm.

[0053] 2) Slowly add 3 mL of tetrabutyl titanate stock solution dropwise to 60 mL of high-viscosity reaction system. The dropping rate is 0.10 mL / min. After the addition is complete, seal and stir for 4 hours.

[0054] 3) After stirring, centrifuge and dry at 80 degrees Celsius for 12 hours to obtain the product.

[0055] The products obtained in the above embodiments and comparative examples were characterized, and the characterization methods and results are as follows:

[0056] Taking Example 1 as an example, the scanning electron microscope image of the prepared two-dimensional titanium dioxide microwire is as follows: Figure 1 and Figure 2 As shown. Figure 1 and Figure 2 The images are scanning electron microscope (SEM) images taken at magnifications of 2 micrometers and 200 nm, respectively. As can be seen from the accompanying figures, two-dimensional titanium dioxide microwires were prepared using the method described in Example 1.

[0057] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "implementation," "specific implementation," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of the present invention.

[0058] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing titanium dioxide microwires using a high-viscosity system, characterized in that, include: A high-viscosity system is provided, wherein the high-viscosity system is an aqueous solution of guar hydroxypropyltrimethylammonium chloride, and the high-viscosity system is subjected to high-speed shearing treatment; Tetrabutyl titanate was added to the high-viscosity system, stirred, centrifuged, and dried to obtain the titanium dioxide microwires; The concentration of the aqueous solution of guar hydroxypropyltrimethylammonium chloride is 0.6‰~1.2‰ (w / w), and the viscosity of the aqueous solution of guar hydroxypropyltrimethylammonium chloride is 1.7-5.2 Pa·s; The high-speed shearing process is performed at a speed of 7000-10000 revolutions per minute; The volume ratio of the tetrabutyl titanate to the high viscosity system is (1.0~4.5):(50~80).

2. The method according to claim 1, characterized in that, The tetrabutyl titanate was added to the high-viscosity system at a dropping rate of 0.05-0.10 mL / min.

3. The method according to claim 1, characterized in that, The drying temperature is 70~100 degrees Celsius.

4. A titanium dioxide micron wire, characterized in that, Prepared by the method according to any one of claims 1 to 3.

5. The use of titanium dioxide microwires in the field of photocatalytic nanomaterials, wherein the titanium dioxide microwires are those described in claim 4.

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