Method for preparing pure gold redstone type titanium dioxide nanorod

A kind of preparation method of pure rutile titanium dioxide nanorodTechnical field

[0001] The present invention belongs to a method for preparing inorganic nanomaterials, and specifically relates to a method for preparing pure gold-red titanium dioxide nanorods.

Background technique

[0002] Nano titanium dioxide (Ti0₂) Is a kind of multifunctional inorganic nano material, the particle size of which is between 1~100nm at least in one dimension, it has the characteristics of antibacterial, ultraviolet absorption, non-toxic, good biocompatibility, stable properties, low price It is widely used in cosmetics, plastics, textiles, automobiles, building materials, biomedicine, aerospace and other fields. The common crystal forms of titanium dioxide are rutile, anatase and brookite. Among them, rutile nano-titanium dioxide becomes an ideal ultraviolet shielding agent due to its stable properties, high refractive index and relatively low photocatalytic activity, and has broad application prospects.

[0003] The traditional chemical preparation of rutile nano-titanium dioxide is mainly divided into a gas phase method and a liquid phase method. The nano titanium dioxide produced by the gas phase method has the advantages of high chemical activity, good monodispersity, and less agglomeration, but the particles are mainly spherical, and require high temperature conditions, which require high production equipment. In contrast, the use of liquid phase method to prepare nano-TiO2 has the advantages of controllable powder particle size, lower synthesis temperature, and low cost. It is currently a method widely used in laboratories and industry.

[0004] The liquid phase method is mainly divided into sol-gel method, liquid phase precipitation method and solvothermal method. The traditional sol-gel method and liquid phase precipitation method both require high-temperature solid-phase reaction, so that the hydrated nano-titania undergoes a transformation process from amorphous to anatase type to rutile type. However, the high-temperature calcination process consumes a lot of energy, costs a lot, and often causes the rapid growth of nano-crystalline grains, and even causes the sintering of nano-particles, resulting in large-scale nano-titania grains, wide distribution, and mostly spherical , The specific surface area is reduced. These will affect the performance of nano-titanium dioxide itself and limit its application in certain aspects. Therefore, the development of preparation methods and processes that do not need to go through high-temperature tempura burning has become the direction of people's efforts in recent years. [0005] Solvothermal method is the main method for preparing oxide grains without high temperature calcination. Solvothermal method refers to the use of water or organic solvent as the reaction medium in a special closed reaction vessel (such as an autoclave) to create a high temperature and high pressure reaction environment by heating the reaction vessel to dissolve normally insoluble or insoluble substances And recrystallize to obtain the corresponding powder. Solvothermal method is mostly used to prepare anatase-type nano-titanium dioxide, and it can also be used to prepare rutile-type titanium dioxide. Grade rutile titanium dioxide. When the solvothermal method is used to prepare rutile nano-titanium dioxide, in order to control Crystal type usually requires ion doping. For example, CN102205418A uses a hydrothermal method with a doping mass ratio of 1% to 30% iron in a closed reactor to prepare rutile nano-titania at a temperature of 110 to 140°C. However, the amount of dopant is usually large, and the doped ion will remain in the final product as an impurity, which may have an impact on the light absorption and catalytic activity of the product nano titanium dioxide. In addition, the solvothermal method needs to be carried out in a closed reaction vessel at a higher temperature and pressure, which puts forward higher requirements on production conditions, costs and operating techniques.

[0006] In recent years, some improved liquid phase methods have also appeared for the preparation of rutile nano-titania. Such as CN101805017A, CN101456583A and CN101698507A, adopt an improved liquid-phase precipitation method, mainly prepare titanium source dispersion with titanium tetrachloride or titanium sulfate, and adjust the pH with inorganic alkali (mainly sodium hydroxide, potassium hydroxide or ammonia, etc.) , And then heated to prepare rutile nano-titanium dioxide. This method requires the addition of an inorganic base to adjust the pH value of the system, and some also need to add a mineralizer (stannous chloride, tin chloride, etc.), which has higher requirements for operation and drugs. CN101062781A and CN1631795A, using

The improved sol-gel method uses titanium tetrachloride as the titanium source, and undergoes the steps of sol aging, heating and hydrolysis, etc., to prepare rutile nano-titanium dioxide. However, these improved sol-gel methods usually require an external stabilizer to stabilize the sol, and require a long period of aging, which makes the reaction cycle longer and higher production costs.

[0007] Under the same number of particles, rod-shaped and needle-shaped rutile titanium dioxide have a higher specific surface area, but there are only a few patent reports on the preparation method. For example, CN102295309A uses orthotitanic acid slurry as raw material, and under the condition of adding hydrochloric acid, prepares acicular rutile nano titanium dioxide, but at the same time, it needs to meet a certain heating rate and quenching conditions._oCN101327951A takes titanium dioxide powder as raw material, firstly mixes with lye in an autoclave to prepare a precursor, then adds nitric acid to the precursor, and reacts in the autoclave at a temperature of 160~190°C for 40~60 hours to obtain rutile titanium dioxide Nanorods, but this method is a hydrothermal method that requires an autoclave and requires higher equipment. CN101550595A, Pure rutile titanium dioxide single crystal nanorods are obtained by low-template-free preparation. The reaction belongs to an improved liquid phase deposition method. It requires external alkali and acid solution and closed system heating reaction, and the reaction steps are relatively complicated (it is necessary to prepare a titanium precursor The alcohol solution is added dropwise to the distilled water while stirring. After heating and stirring for a period of time, the alkali solution is added. After sealing, it is heated and stirred, and the precipitate is separated by centrifugation. After washing to neutrality, the precipitate is dissolved in an acid solution, sealed, heated and stirred, centrifuged to obtain the precipitate, and the precipitate is dissolved in the distilled water to obtain the final product), the process cycle is long. In CN102285685A, titanium dioxide powder is used as a raw material to prepare a rod-shaped rutile titanium dioxide mesogen, which has a length of 200~300nm and a diameter of 50~80nm. It is composed of 3~5nm ultrafine nanowires. However, the disadvantage of this method is the periodicity. Longer (the shortest reaction period is more than 7 days), the rod-shaped rutile titanium dioxide mesogenic size is larger. The preparation method disclosed in CN102503166A is not a single crystal dispersed independently, but a rutile titanium dioxide nanorod array film on a conductive glass substrate. Its application field is also very different from dispersible nanoparticles, and it is mainly used for solar cells. The photo-anode materials of the above are not repeated here.

Summary of the invention

[0008] The purpose of the present invention is to solve the above-mentioned problems, thereby providing a method for preparing pure rutile titanium monoxide nanorods with low equipment investment, simple process, low raw material cost, and mild preparation conditions.

[0009] The method for preparing pure rutile titanium dioxide nanorods of the present invention is to prepare pure rutile with controllable morphology under normal pressure and low temperature environment, using water as the dispersion medium and using the hydrolysis reaction of the titanium source material Titanium dioxide nanorods, the preparation method includes the following steps:

[0010] (1) Under normal pressure and room temperature, the iron-containing crystal form control agent is added to water, stirred and mixed uniformly, and heated to 60~

100°C, get a dispersion system of iron-containing crystal form control agent;

[0011] (2) Under normal pressure, the titanium source was added to the dispersion system of the iron-containing crystal form control agent obtained in step (1), and reacted at a constant temperature for 5 to 30 hours to obtain a reaction liquid;

[0012] (3) Under normal pressure, the reaction solution obtained in step (2) is separated by centrifugation or filtration, and the resulting precipitate is washed to obtain a reaction product;

[0013] (4) Dry the reaction product obtained in step (3) (generally, the drying time is 2-10 hours) to obtain pure rutile titanium dioxide nanorods.

[0014] The average length of the pure rutile titanium dioxide nanorods is 30 to 80 nm, and the diameter is 5 to 10 nm.

01%~5%. [0015] Step (1) The mass ratio of the iron-containing crystal form control agent to water in the dispersion system of the iron-containing crystal form control agent is 0.01%~5%.

[0016] The titanium source is added to the dispersion system of the iron-containing crystal form control agent obtained in step (1), the iron-containing crystal form control agent is 0.5%~50% of the quality of the titanium source, titanium source The measurement is calculated based on the material of the pure titanium source.

[0017] The amount of the iron-containing crystal form control agent is added according to 0.5% to 50% of the mass of the titanium source, and the atomic ratio of iron/titanium is equivalent to 0.5% to 50%. By adjusting the amount of iron-containing crystal form control agent, the morphology of the product pure rutile titanium dioxide nanorods can be effectively adjusted. The smaller the amount of iron-containing crystal form control agent, the greater the aspect ratio of the pure rutile titanium dioxide nanorods. However, if the addition amount of the iron-containing crystal form control agent is too low, the product will be a mixed crystal of rutile type and anatase type; on the contrary, the addition amount of the iron-containing crystal form control agent is too high, which is a waste and easy to Impurities are introduced into the product.

[0018] The iron-containing crystal form control agent is selected from the group consisting of iron trichloride (FeClJ, iron nitrate (Fe(N0₃)₃)>iron sulfate (Fe₂(S0₄)₃) And iron oxide (Fe₂0₃) One or more of them. Among them, iron trichloride (FeCl₃), iron nitrate (Fe(N0₃)₃), iron sulfate (Fe₂(S0₄)₃) Belongs to iron salt, which can be dissolved in water to form a solution; iron oxide (Fe₂0₃) It is an iron oxide, insoluble in water, but it only needs to be uniformly dispersed in water by stirring. In the acidic environment of the titanium source, iron ions will be produced to control the crystal form of titanium dioxide, and there will not be any in the system when the amount is appropriate. The solid residue will not affect the purity of the product.

[0019] The titanium source is selected from titanium trichloride (TiCl₃) Or its aqueous solution, titanium tetrachloride (TiCl₄) Or its aqueous solution, titanium sulfate (Ti(so₄)₂) Or its aqueous solution, tetrabutyl titanate (Ti(0C₄H₉)₄) Or its aqueous solution and isopropyl titanate (Ti(0C₄H₉)₄) Or one of its aqueous solutions. Wherein, the valence of titanium in the titanium tetrachloride, titanium sulfate, tetrabutyl titanate, and isopropyl titanate is IV, and it can be directly hydrolyzed to form titanium dioxide; the valence of titanium in titanium trichloride is III valence, it is also accompanied by oxidation reaction to form titanium dioxide during hydrolysis.

[0020] In step (2), the constant temperature reaction can be performed without stirring, or the constant temperature reaction can be further performed under stirring, but it is not advisable to stir too fast, otherwise the morphology of the product may agglomerate and transform into a flower-like or star-like shape. Clusters. The stirring rate when performing constant temperature reaction under stirring is 0<stirring rate W 300r/min_o

[0021] The solvent for washing is selected from one or more of water, methanol, ethanol, and acetone.

[0022] The water and washing water described in step (1) may be distilled water, deionized water or tap water. Since the addition amount of the iron-containing crystal form control agent in the preparation method of the present invention is small, in order to avoid interference from other ions and ensure the purity of the product, distilled water and deionized water are preferred.

[0023] The drying described in step (4) is to remove the solvent for washing remaining in the product of step (3), and there are many mature methods, such as freeze drying, spray drying, flash drying, blast drying and vacuum The technology of drying is well known in the industry. In actual operation, a more economical method can be selected according to the output, so there is no need to go into details.

[0024] In the preparation method of the present invention, water is used as the dispersion medium, and pure rutile titanium dioxide nanorods with controllable morphology can be prepared under mild atmospheric conditions. The resulting product is pure rutile at room temperature without heat treatment. It solves the problems of poor crystal dispersion, easy agglomeration of particles, and small specific surface area caused by high temperature heat treatment in the existing method for preparing rutile nano-titanium dioxide, simple equipment requirements, strong operability, and low production cost. The obtained titanium dioxide The nanorods are of pure rutile type with high crystallinity. The product has good dispersibility and large specific surface area. It can effectively control the aspect ratio of pure rutile titanium dioxide nanorods by adjusting the content of the iron-containing crystal form control agent. The obtained pure rutile titanium dioxide nanorods have good ultraviolet absorption capacity.

Description of the drawings

[0025] Figure 1. The addition of ferric chloride in Examples 1 to 4 of the present invention were (a) 0.5%; (b) 1%; (c) 5%; (d) 50% prepared The X-ray diffraction pattern of pure rutile titanium dioxide nanorods. The standard X-ray polycrystalline diffraction characteristic peaks of rutile titanium dioxide are indicated on the abscissa of the figure.

[0026] Figure 2. The addition of ferric chloride in Examples 1 to 4 of the present invention were (a) 0.5%; (b) 1%; (c) 5%; (d) 50% prepared TEM picture of pure rutile titanium dioxide nanorods.

[0027] Figure 3. The addition of ferric chloride in Examples 1 to 4 of the present invention were (a) 0.5%; (b) 1%; (c) 5%; (d) prepared by 50% Ultraviolet-visible absorption spectrum of pure rutile titanium dioxide nanorods.

[0028] Figure 4. The addition of ferric chloride in Examples 1 to 4 of the present invention were (a) 0.5%; (b) 1%; (c) 5%; (d) prepared by 50% Raman spectra of pure rutile titanium dioxide nanorods.

Detailed ways

Example 1

[0030] (1) Under normal pressure and room temperature, 0.2 g of ferric chloride was added to 1kg (1L) of steamed water, stirred and mixed uniformly, and heated to 100° C. to obtain a mixture of ferric chloride and water A dispersion system of ferric chloride with a mass ratio of 0.02%;

[0031] (2) Under normal pressure, add 200g of titanium trichloride hydrochloric acid solution to the dispersion system of ferric trichloride obtained in step (1), at a stirring rate of 100r/min and a temperature of 100°C Perform a constant temperature reaction for 24 hours to obtain a reaction solution; wherein, the titanium trichloride hydrochloric acid solution contains 40 g of pure titanium trichloride, and the ferric chloride is 0.5% of the quality of the pure titanium trichloride;

[0032] (3) Under normal pressure, the reaction solution obtained in step (2) is separated by filtration, and the obtained precipitate is washed with distilled water several times to obtain a reaction product;

[0033] (4) The reaction product obtained in step (3) was freeze-dried at a temperature of -50° C. for 5 hours to obtain a pure rutile titanium dioxide nanorod powder.

[0034] The X-ray polycrystalline diffraction test results of the obtained pure rutile titanium dioxide nanorods are shown in Figure 1. The titanium dioxide is pure rutile (card JCPDS21-1276) and has good crystallization properties.

[0035] Embodiment 2-16

[0036] The basic steps are the same as in Example 1, and the specific parameters are shown in Table K

[0037] Comparative Example 1

[0038] (1) At normal pressure and room temperature, the lkg of steamed house water is heated to 100 ° C;

[0039] (2) Under normal pressure, add 200g of titanium trichloride hydrochloric acid solution to the distilled water obtained in step (1), and conduct a constant temperature reaction at a stirring rate of 100r/min and a temperature of 100°C for 24 hours to obtain Reaction liquid; wherein, the titanium trichloride hydrochloric acid solution contains 40g of pure titanium trichloride;

[0040] (3) Under normal pressure, the reaction solution obtained in step (2) is separated by filtration, and the obtained precipitate is washed with distilled water several times to obtain a reaction product;

[0041] (4) The reaction product obtained in step (3) is vacuum dried at a temperature of 80° C. for 5 hours to obtain a spherical nanometer titanium dioxide powder of mixed crystal of rutile type and anatase type.

[0042] Comparative Example 2

[0043] (1) Under normal pressure and room temperature, add 0.04 g of ferric chloride to 1kg of steamed water, stir and mix uniformly, and heat to 100° C. to obtain a mass ratio of ferric chloride to water of 0 . 004% ferric chloride dispersion system;

[0044] (2) Under normal pressure, add 200g of titanium trichloride hydrochloric acid solution to the dispersion system of ferric trichloride obtained in step (1), at a stirring rate of 100r/min and a temperature of 100°C Perform a constant temperature reaction for 24 hours to obtain a reaction solution; wherein the titanium trichloride hydrochloric acid solution contains 40 g of pure titanium trichloride, and ferric chloride is 0.1% of the mass of pure titanium trichloride;

[0045] (3) Under normal pressure, the reaction solution obtained in step (2) is separated by filtration, and the obtained precipitate is washed with distilled water several times to obtain a reaction product;

[0046] (4) The reaction product obtained in step (3) is freeze-dried at a temperature of -50° C. for 5 hours to obtain a mixed crystal of rutile type and anatase type nano titanium dioxide powder.

[0047] Comparative Example 3

[0048] (1) Under normal pressure and room temperature, add 1 g of ferric chloride to 1 kg of steamed water, stir and mix evenly, and heat to

100° C., to obtain a dispersion system of ferric chloride with a mass ratio of ferric chloride to water of 0.1%;

[0049] (2) Under normal pressure, add 200g of titanium trichloride hydrochloric acid solution to the dispersion system of ferric trichloride obtained in step (1), at a stirring rate of 500r/min and a temperature of 100°C Perform a constant temperature reaction for 24 hours to obtain a reaction solution; wherein, the titanium trichloride hydrochloric acid solution contains 40g of pure titanium trichloride, and the ferric chloride is 2.5% of the quality of the pure titanium trichloride;

[0050] (3) Under normal pressure, the reaction solution obtained in step (2) is separated by filtration, and the obtained precipitate is washed with distilled water several times to obtain a reaction product;

[0051] (4) The reaction product obtained in step (3) was freeze-dried at a temperature of -50° C. for 5 hours to obtain a pure rutile nano-titanium dioxide powder with a flower-like morphology with a diameter of 200 to 300 nm.

[0052] It can be seen from FIG. 1 that the titanium dioxide nanorods of Examples 1 to 4 are pure rutile.

[0053] It can be seen from FIG. 2 that the pure rutile titanium dioxide nanorods of Examples 1 to 4 are in the shape of a single rod with complete morphology and good dispersibility, with a large specific surface area. Take the pure rutile titanium dioxide nanorods of Example 3 For example, its specific surface area is as high as 154. 90m²/go With the increase of ferric chloride, the average length of pure rutile titanium dioxide nanorods is obviously reduced, while the average diameter is basically unchanged, the aspect ratio gradually decreases, and the distribution becomes narrower. It shows that a certain length of pure rutile titanium dioxide nanorods can be prepared by adjusting the addition amount of the iron-containing crystal form control agent.

[0054] It can be seen from the ultraviolet-visible absorption spectrum of FIG. 3 that the prepared pure rutile-type titanium dioxide nanorods have excellent ultraviolet absorption capacity and can strongly absorb ultraviolet rays below 400 nm; no obvious absorption is detected in the visible light region. , Indicating that there are almost no impurities such as iron oxide that can absorb in the visible light region.

[0055] It can be seen from the Raman spectrum of FIG. 4 that the pure rutile titanium dioxide nanorods prepared by adding different amounts of ferric chloride have the same peak positions in the Raman spectrum, indicating that there is no iron doping into A condition that causes lattice distortion in a titanium dioxide crystal.

[0056] From the X-ray fluorescence spectrum analysis results in Table 2, it can be seen that the Fe element content in the pure rutile titanium monoxide nanorods obtained in Examples 1 to 4 is extremely low, and the measured value does not vary with the addition amount of the iron-containing crystal form control agent It increases and changes significantly, and the characteristic peak of Fe does not appear in the X-ray photoelectron spectroscopy, indicating that there is no iron salt adsorbed on the surface of the titanium dioxide crystal. These experiments further show that the iron-containing crystal form control agent will not remain in the product, and the product purity is high.

[0057] Table 1

[0058]

<td colspan="2">Example Titanium Source</td><td>CCA</td><td>CCA/ water (%)</td><td>CCA/TS(%)</td><td>Reaction temperature (°C)</td><td>Stirring rate (17 min)</td><td>Average product size (length x diameter x nm)</td>

<td>1</td><td>Titanium trichloride</td><td>Ferric chloride</td><td>0.02</td><td>0 5</td><td>100</td><td>100</td><td>70x9</td>

<td>2</td><td>Titanium trichloride</td><td>Ferric chloride</td><td>0.04</td><td>1</td><td>100</td><td>100</td><td>60x9</td>

<td>3</td><td>Titanium trichloride</td><td>Ferric chloride</td><td>0.2</td><td>5</td><td>!00</td><td>100</td><td>50 four</td>

<td>4</td><td>Titanium trichloride</td><td>Ferric chloride</td><td>2</td><td>50</td><td>100</td><td>100</td><td>3X8</td>

<td>$</td><td>Titanium trichloride</td><td>Iron oxide</td><td>5</td><td>23</td><td>80</td><td>200</td><td>50x8</td>

<td>6</td><td>Titanium tetrachloride</td><td>Iron oxide</td><td>0 02</td><td>0.2</td><td>80</td><td>300</td><td>80x10</td>

<td>7</td><td>Titanium tetrachloride</td><td>Iron oxide</td><td>02</td><td>2</td><td>70</td><td>30(Ta</td><td>60-10</td>

<td>8</td><td>Titanium tetrachloride</td><td>Iron oxide</td><td>2</td><td>20</td><td>60</td><td>300</td><td>40x9</td>

<td>9</td><td>Titanium Sulfate</td><td>Ferric sulfate</td><td>0.01</td><td>2.3</td><td>80</td><td>0</td><td>50x8</td>

<td>10</td><td>Titanium Sulfate</td><td>Ferric sulfate</td><td>0.05</td><td>4 6</td><td>100</td><td>0</td><td>407</td>

<td>11</td><td>Titanium Sulfate</td><td>Ferric sulfate</td><td>().1</td><td>9.2</td><td>6()</td><td>0</td><td>35x6</td>

<td>12</td><td>Tetrabutyl titanate</td><td>Ferric nitrate</td><td>0.3</td><td>0.68</td><td>60</td><td>200</td><td>845</td>

<td>13</td><td>Tetrabutyl titanate</td><td>Ferric nitrate</td><td>0.4</td><td>34</td><td>70</td><td>200</td><td>60^5</td>

<td>14</td><td>Tetrabutyl titanate</td><td>Ferric nitrate</td><td>1</td><td>6.8</td><td>9()</td><td>200</td><td>4()x5</td>

<td>15</td><td>Isopropyl titanate</td><td>Ferric nitrate</td><td>1</td><td>16</td><td>80</td><td>200</td><td>50x7</td>

<td>16</td><td>Isopropyl titanate</td><td>Ferric sulfate</td><td>4</td><td></td><td>60</td><td>200</td><td>30x7</td>

[0059] Description: CCA-iron-containing crystal form control agent Tin S-titanium source

[0060] Table 2 X-ray fluorescence spectrometry to determine the purity and Fe content of the products of Comparative Example 1 and Examples 1 to 4

[0061]

<td></td><td>The amount of ferric chloride (wt%)</td><td>The content of TiCh in the product (wt %)</td><td>The content of Fe in the product (wt%)</td>

<td>Comparative example 1</td><td>0</td><td>99.3</td><td>0.0247</td>

<td>Example 1</td><td>05</td><td>99.2</td><td>0.035K</td>

<td>Example 2</td><td>1</td><td>99.4</td><td>0.0260</td>

<td>Example 3</td><td>S</td><td>99.4</td><td>0.0314</td>

<td>Example 4</td><td>50</td><td>99.4</td><td>0.0527</td>