Preparation method of titanium dioxide nano powder and titanium dioxide nano powder prepared by same

Method for preparing titanium dioxide nanopowder and technical field of titanium dioxide nanopowder prepared by the method

[0001] The present invention relates to a method for preparing nanopowders, in particular to a method for preparing titanium dioxide nanopowders and titanium dioxide nanopowders prepared by the method.

Background technique

[0002] In recent years, the development of global nanotechnology is in the ascendant. The successful development of many nanomaterials has actually improved people's lives and created unlimited business opportunities. Because the semiconductor energy level of titanium dioxide (TTI02) has a wide energy band, it is widely used as a multifunctional photocatalyst. Although the semiconductor energy level of zinc oxide also has a wide energy band and can also be used as a multifunctional catalyst material, its chemical stability is poor (for example, it is not resistant to acid solutions). Therefore, most nano-photocatalyst materials are mainly titanium dioxide, which is currently the most widely used nano-material.

[0003] There are many methods for preparing titanium dioxide nanopowders, which can be mainly divided into physical methods and chemical methods. The physical method is the earliest preparation method, which uses physical methods such as vapor phase condensation and high-energy ball milling to obtain nanopowders. The principle of the gas phase condensation method is to use various methods to evaporate or volatilize substances into the gas phase, and use special techniques to condense (such as liquid nitrogen) to form nuclei to obtain nanopowders. The powder prepared by this method has high purity, uniform particle size distribution, and controllable size, which is suitable for the production of high melting point nano-metal particles or nano-particle films. The high-energy ball milling method uses the huge energy of the ball mill to rotate and vibrate to crush the raw materials into nano-scale particles. Its advantages are simple operation and easy realization of continuous production, but its disadvantages are uneven particle size and easy introduction of impurities. Chemical method is another method of preparing nano-powders, and some chemical reactions are involved in the process. The chemical methods used to prepare micropowder and nanopowder mainly include precipitation method, hydrolysis method, sol-gel method, hydrothermal method, spray method, redox method, laser synthesis method, and electrochemical preparation method. The above is only a rough classification. In the preparation process of titanium dioxide nanopowder, the above methods can also be used in combination. For example, precipitation methods and spray methods often involve hydrolysis and redox reactions; hydrothermal methods are often combined with sol-gel methods to prepare nanopowders with different morphologies, such as nanowires, nanorods, nanotubes, Nano microspheres and so on.

[0004] Among the various methods for preparing titanium dioxide nanopowders, the spray cracking method is currently one of the main processes for commercializing titanium dioxide nanopowders. This process can be used to obtain nanopowders with uniform particle size and stable quality. Rice noodles. In addition, the sol-gel method and hydrothermal method can be used to prepare titanium dioxide nanopowders with various morphologies; and the pH value, hydrothermal temperature, reaction time and solution concentration of the reaction solution can be adjusted by controlling the pH value, hydrothermal temperature, reaction time and solution concentration. Meter size. This is currently the most common way to obtain diverse nanostructures.

[0005] With the rapid development of the technology industry, titanium dioxide nanopowders with various morphologies are increasingly used in various fields. Generally, when preparing microspherical titanium dioxide nanopowders, hydrothermal method, microemulsion method, template method, etc. are used. However, the above methods require relatively expensive production equipment, and are not conducive to mass and continuous production; in addition, the uniformity of powders prepared by these methods still needs to be improved. Therefore, it is necessary to develop a method for preparing microspherical titanium dioxide nanopowders, which is suitable for mass production, has low manufacturing cost, and the prepared titanium dioxide nanopowders have a uniform particle size.

Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing titanium dioxide nanopowder, which can be used to obtain microspherical titanium dioxide nanopowder with uniform particle size and low cost.

[0007] In order to solve the above technical problems, the embodiments of the present invention provide technical solutions as follows:

[0008] A method for preparing microspherical titanium dioxide nanopowders includes the following steps:

[0009] (a) Adding a titanium precursor to deionized water to obtain a titanium precursor solution;

[0010] (b) Adding a surfactant to deionized water to obtain a surfactant solution;

[0011] (c) adding the surfactant solution to the titanium precursor solution to obtain a mixed solution;

[0012] (d) Collect microspherical titanium dioxide nanopowders in the mixed solution;

[0013] (e) Drying the microspherical titanium dioxide nanopowder.

[0014] Wherein, the titanium precursor is titanium tetrachloride.

[0015] Wherein, the titanium precursor is a titanium alkoxide.

[0016] Wherein, the alkyl group of the titanium alkoxide has 1 to 6 carbon atoms.

[0017] Wherein, the surfactant is ethylene glycol.

[0018] Wherein, the surfactant is an ethylene glycol derivative.

[0019] Wherein, step (a) is performed at a temperature of 3 to 10°C.

[0020] Wherein, step (a) is performed under an inert gas.

[0021] Wherein, the inert gas is nitrogen or nitrogen.

[0022] Further, after obtaining the titanium precursor solution, the titanium precursor solution is left standing at a temperature of 4 to 15° C. for 3 to 48 hours.

[0023] Wherein, the particle size of the microspherical titanium dioxide nanopowder changes with the molar ratio of the titanium precursor and the surfactant.

[0024] The embodiment of the present invention also provides a microspherical titanium dioxide nanopowder, which is prepared by the above-mentioned method for preparing the microspherical titanium dioxide nanopowder.

[0025] The present invention also provides a method for preparing titanium dioxide nano-films to form micro-spherical titanium dioxide nano-films on various substrates.

[0026] The present invention mainly uses hydrolysis and precipitation methods to prepare microspherical titanium dioxide nanopowders; during the hydrolysis process, the molar ratio of the titanium precursor and the surfactant is adjusted to control the microspherical titanium dioxide nanopowders Particle size. According to the preparation method of the present invention, a titanium dioxide nanopowder with a microsphere structure can be generated in a short time, the diameter of which is between 50 nm and 2000 nm, and the quality is good.

[0027] The microspherical titanium dioxide nanopowder prepared by the above method is added to water, an aqueous solvent, or an oily solvent, and then a dispersant such as organic small molecules, oligomers, and polymers is added to form a slurry Or solution. Among them, anionic and cationic surfactants can also be added selectively. Then, screen printing, spin coating, spray coating, etc. are used to form microspherical titanium dioxide nano-films on the substrate.

Description of the drawings

[0028] FIG. 1 is a scanning electron microscope image of the microspherical titanium dioxide nanopowder according to the embodiment of the present invention. The particle size of the microspherical titanium dioxide nanopowder shown in 1(a) is 650 to 750nm; l(b) The particle size of the microspherical titanium dioxide nanopowder shown in) is 550 to 650nm; 1 (c) the particle size of the microspherical titanium dioxide nanopowder is 450 to 550nm; 1 (d) the microspherical titanium dioxide nanopowder is shown The particle size of the powder is 300 to 400nm;

[0029] FIG. 2 is an X-ray diffraction diagram of a microspherical titanium dioxide nanopowder according to an embodiment of the present invention;

[0030] FIG. 3 is a scanning electron microscope image of a microspherical titanium dioxide nano film disposed on a substrate.

Detailed ways

[0031] In order to make the technical problems, technical solutions, and advantages to be solved by the embodiments of the present invention clearer, the following will describe in detail with reference to the accompanying drawings and specific embodiments.

[0032] The embodiments of the present invention aim at the problem that when preparing microspherical titanium dioxide nanopowders in the prior art, relatively expensive production equipment is required, and is not conducive to large-scale and continuous production, a microspherical titanium dioxide nanopowder is provided. The preparation method and the titanium dioxide nanopowder prepared by the method can obtain titanium dioxide nanopowder suitable for mass production, low manufacturing cost, and uniform particle size.

[0033] Keep 200 mL of deionized water in an ice bath environment with a temperature between 3 and 10° C., and can selectively pass in nitrogen or nitrogen. While stirring at high speed, add the titanium precursor dropwise to deionized water at a rate of 1 to several drops per second to obtain a titanium precursor solution. In one embodiment, the titanium precursor is a titanium alkoxide, where the alkyl group in the titanium alkoxide may have 1 to 6 carbon atoms. In another embodiment, the titanium precursor is titanium tetrachloride. Continue to stir for about 1 to 5 hours; then let it stand for 3 to 48 hours at a temperature of 4 to 15°C. Add ethylene glycol as a surfactant to deionized water to obtain a surfactant solution. Then add this surfactant solution to the aforementioned titanium precursor solution, and stir for 5 to 100 minutes, wherein the molar ratio of titanium precursor/ethylene glycol is 1: 3. In another embodiment, ethylene glycol oligomers or ethylene glycol polymers may be used instead of ethylene glycol. The obtained mixture is sealed with plastic wrap and aluminum foil, and placed in an oven at a temperature of 10 to 90° C. to react for 10 to 200 minutes; then the powder is collected by filtration or centrifugation. The above-mentioned powder is washed with deionized water at least three times to remove the residual solvent; and then dried in an oven at a temperature between 60 and 500 Ό, thereby obtaining the microspherical titanium dioxide nanopowder of the present invention, which has a uniform The particle size is between 650 and 750nm. Figure 1 (a) shows the scanning electron microscope (SEM) image of the microspherical titanium dioxide nanopowder, and Figure 2 shows its X-ray diffraction image.

[0034] Changing the molar ratio of the titanium precursor to the ethylene glycol can change the particle size of the microspherical titanium dioxide nanopowder. As shown in Table 1.

[0035] Table 1

[0036]

<td colspan="2">Mol ratio (titanium precursor/glycol)</td><td>Particle size of microspherical titanium dioxide nanopowder</td><td>SEM image</td>

<td>1</td><td>3</td><td>650 To 750nm</td><td>Figure 1(a)</td>

<td>1</td><td>5</td><td>550 To 650nm</td><td>Figure 1(b)</td>

<td>1</td><td>7</td><td>450 To 550nm</td><td>Figure 1(c)</td>

<td>1</td><td>9</td><td>300 To 400nm</td><td>Figure 1(d)</td>

[0037] Mix 6g of the aforementioned microspherical titanium dioxide nanopowder with 1mL of acetic acid and stir for three minutes; add 5mL of deionized water and stir for 3 minutes to make it uniformly mixed; then add 15mL of ethanol, 20g of terpineol, and After 30g of ethyl cellulose, stir for 12 hours to make it uniformly dispersed, and the preparation of the microspherical titanium dioxide nano slurry is completed.

[0038] By screen printing, the aforementioned microspherical titanium dioxide nanopaste is coated on a transparent conductive glass substrate and sintered at a high temperature to remove organic substances. The sintering temperature is between 300 and 600°C. The sintering time is between 1 to 5 hours; and then cooled to room temperature, a microspherical titanium dioxide nano film with a thickness of 1 to 10 microns can be formed on the substrate, which can be used for, for example, the transparent electrode of solar cells. The hardness of the film is between 3B and 6H pencil hardness. Figure 3 is a scanning electron microscope image of a microspherical titanium dioxide nano film disposed on a substrate.

[0039] In the method embodiments of the present invention, the sequence numbers of the steps cannot be used to limit the sequence of the steps. For those of ordinary skill in the art, the steps are The successive changes of are also within the protection scope of the present invention.

[0040] The above are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements and modifications can be made. These Improvements and modifications should also be regarded as the protection scope of the present invention.