CN104843779B - A kind of hollow ball-shape rutile titanium dioxide is mesomorphic and preparation method thereof - Google Patents

Abstract

The hollow spherical rutile titanium dioxide mesogen disclosed by the present invention is a hollow spherical structure assembled from rutile crystal nanorods, the diameter of the hollow spheres is 3.0-6.0 μm, the length of the nanorods is 200-500 nm, and the width is 100-250 nm. The preparation steps are as follows: dissolving potassium titanium oxalate in hydrogen peroxide reaction solution added with nitric acid, and keeping the temperature at 80 ^o C for 48 to 72 hours. The invention does not require a high-temperature and high-pressure hydrothermal environment, and the hollow spherical rutile titanium dioxide mesocrystal is obtained in the next step at a low temperature. The preparation route is simple and easy, the cost is low, and the powder yield is high. It can be applied to the fields of photocatalysis, lithium-ion batteries, and the like.

Description

A kind of hollow spherical rutile titanium dioxide mesocrystal and preparation method thereof

technical field

The invention relates to a hollow spherical rutile titanium dioxide mesocrystal and a preparation method thereof, belonging to the field of preparation of metal oxide functional materials.

Background technique

Titanium dioxide is one of the few inorganic materials that are very stable in both acidic and alkaline conditions. Due to its excellent biocompatibility, non-toxic and harmless, sufficient resources and low cost, it is widely used in photocatalysis, Electrochromic, dye-sensitized solar cells and lithium-ion batteries have broad application prospects, and are increasingly becoming a key material to solve global environmental and energy problems. Mesogenic structure materials have abundant mesopores, and their atomic arrangement and orientation are close to those of single crystals, so their physical and chemical properties are similar to those of single crystals, and their specific surface area is significantly higher than that of single crystals, which has become one of the research hotspots in recent years. At present, the preparation methods of titania mesogens mainly include hydrothermal/solvothermal methods, and topological transformation of precursors. Among them, the hydrothermal/solvothermal method requires a high temperature and high pressure environment, high energy consumption, poor environmental friendliness, great safety hazards, and high industrialization costs; while the topology transformation method requires the preparation of suitable precursors, and the subsequent processing of the precursors TiO2 mesogens are obtained. The morphologies of titanium dioxide crystals that have been obtained so far include nanorods, nanoflowers, hollow nanobricks, dumbbell-shaped and sheet-like structures, but there is no low-temperature one-step method to directly prepare hollow spherical structures stacked by rutile crystal nanorods.

Contents of the invention

The object of the present invention is to provide a hollow spherical rutile titanium dioxide mesocrystal prepared by one-step method with simple process, no template and low cost and its preparation method.

The hollow spherical rutile titanium dioxide mesogen of the present invention is a hollow spherical structure assembled from rutile crystal nanorods, the diameter of the hollow spheres is 3.0-6.0 μm, the length of the nanorods is 200-500 nm, and the width is 100-250 nm.

The preparation method of hollow spherical rutile titanium dioxide mesogen of the present invention, its concrete steps are as follows:

1) Add nitric acid with a mass concentration of 63% to a hydrogen peroxide solution with a mass concentration of 10%, and the volume ratio of nitric acid and hydrogen peroxide solution is 0.02-0.06;

2) Add potassium titanium oxalate to the mixed solution of nitric acid and hydrogen peroxide in step 1), so that the concentration of potassium titanium oxalate in the solution is 100-200 mmol/L, mix thoroughly by ultrasonic oscillation, then seal and keep warm at 80 ^o C After 48-72 hours, centrifuge, wash and dry to obtain hollow spherical rutile titanium dioxide mesocrystals.

The invention realizes the low-temperature one-step preparation of the hollow spherical structure rutile titanium dioxide mesocrystal for the first time. Using potassium titanium oxalate as the titanium source, the hollow spherical rutile titanium dioxide mesogens with high crystallinity were prepared at a low temperature of 80 ^o C by the hydrolysis-dissolution-redeposition process of potassium titanium oxalate in hydrogen peroxide solution dissolved in nitric acid. The hollow spherical structure is a secondary structure assembled from nanorods as the basic unit. The selected area electron diffraction characterization of a single nanorod shows that the synthesized nanorod has a structure similar to a single crystal, and mespores are distributed in the single crystal nanorod. The synthesized hollow spherical TiO mesogens have a wide range of applications in many fields such as photocatalysis, photoelectrocatalysis, solar cells, gas sensors, biomaterials, and lithium-ion batteries.

Description of drawings

Fig. 1 is the low-magnification SEM photo of the hollow spherical titanium dioxide mesogen prepared in embodiment 1;

Fig. 2 is the high-magnification SEM photo of the hollow spherical titanium dioxide mesogen prepared in embodiment 1;

Fig. 3 is the XRD spectrum of the hollow spherical titanium dioxide mesogen prepared in embodiment 1;

Fig. 4 is the TEM photograph of the basic constituent unit nanorod of the hollow spherical titania mesogen prepared in embodiment 1;

Fig. 5 is the HRTEM diagram and the FFT transformation diagram of nanorods, the basic constituent units of the hollow spherical titanium dioxide mesogen prepared in Example 1; Fig. a is the HRTEM diagram, and Fig. b is the FFT transformation diagram.

Fig. 6 is the nitrogen adsorption curve of the hollow spherical titanium dioxide mesogen prepared in Example 1;

Fig. 7 is the SEM image of the reaction product of Example 1 after 12 hours of reaction; wherein Fig. a is a low-magnification SEM photo, and Fig. b is a high-magnification SEM photo.

Figure 8 is the SEM picture of the reaction product of Example 1 after 24 hours of reaction; Figure a is a low-magnification SEM photo, and Figure b is a high-power SEM photo.

Figure 9 is the SEM picture of the reaction product of Example 1 after 36 hours of reaction; Figure a is a low-magnification SEM photo, and Figure b is a high-power SEM photo.

Figure 10 is the SEM picture of the reaction product of Example 1 after 48 hours of reaction; Figure a is a low-magnification SEM photo, and Figure b is a high-power SEM photo.

Fig. 11 is the SEM image of the reaction product of Example 1 after 60 hours of reaction; wherein Fig. a is a low-magnification SEM photo, and Fig. b is a high-magnification SEM photo.

Fig. 12 is 12 hours reaction product XRD collection of patterns;

Fig. 13 is the SEM photo of the hollow spherical titanium dioxide mesogen prepared in Example 2;

FIG. 14 is a SEM photo of the hollow spherical titanium dioxide mesogen prepared in Example 3.

detailed description

The present invention is further described below in conjunction with the examples, but the present invention is not limited only to the following examples.

Example 1

1) Take 3mL of nitric acid with a mass percentage of 63% and add it to 50mL of a 10% hydrogen peroxide solution;

2) Add potassium titanium oxalate to the solution obtained in step 1), so that the concentration of potassium titanium oxalate in the solution is 100 mmol/L, and mix thoroughly by ultrasonic oscillation to obtain a dark red transparent solution;

3) Seal the dark red transparent solution obtained in step 2), place it in an oven at 80 ^o C, keep it warm for 72 hours, centrifuge, wash, and dry to obtain a white powder, which is hollow spherical rutile titanium dioxide mesogen.

The hollow spherical rutile titanium dioxide mesogen prepared in this example is shown in Figures 1 and 2. The width of the nanorods is about 100~250nm, and the length is about 200~500nm. The diameter of the hollow sphere assembled by the nanorods is 3.0~6.0μm . The XRD results in Figure 3 confirm that the obtained powder is titanium dioxide with a well-crystallized rutile structure. The TEM characterization results in Figures 4 and 5 show that the basic structural unit of the hollow sphere is the rutile titanium dioxide single crystal (ie mesogen) with mesoporous distribution inside. The low-temperature nitrogen adsorption curve in Fig. 6 shows that the prepared sample has a specific surface area of 32.19m ² /g and an average pore diameter of 11.3nm, further confirming the existence of mesopores.

The time series test in Fig. 7 shows that when the reaction time is 12 hours, the reaction product is a spherical object assembled from nanowires, and it can be known from Fig. 12 that the product is hydrotitanic acid. The reaction time was 24 hours, as shown in Figure 8, the nanowires disappeared, and solid spheres stacked with rod-like structures appeared. As the reaction proceeds, a hollow spherical structure assembled by nanorods is gradually formed, as shown in Figures 9, 10, and 11.

Example 2

1) Take 1 mL of nitric acid with a mass percentage of 63% and add it to 50 mL of a 10% hydrogen peroxide solution;

2) Add potassium titanium oxalate to the solution obtained in step 1), so that the concentration of potassium titanium oxalate in the solution is 100 mmol/L, and mix thoroughly by ultrasonic oscillation to obtain a dark red transparent solution;

3) Seal the dark red transparent solution obtained in step 2), place it in an oven at 80 ^o C, keep it warm for 72 hours, centrifuge, wash, and dry to obtain a white powder.

The SEM photo of the hollow spherical rutile titanium dioxide mesocrystal prepared in this example is shown in Figure 13. The length of the structural unit nanorod is 150-250 nm, and the width is 70-150 nm.

Example 3

1) Take 3mL of nitric acid with a mass percentage of 63% and add it to 50mL of a 10% hydrogen peroxide solution;

2) Add potassium titanium oxalate to the solution obtained in step 1) so that the concentration of potassium titanium oxalate in the solution is 200 mmol/L, and mix thoroughly by ultrasonic oscillation to obtain a dark red transparent solution;

3) Seal the dark red transparent solution obtained in step 2), place it in an oven at 80 ^o C, keep it warm for 72 hours, centrifuge, wash, and dry to obtain a white powder.

The SEM photo of the hollow spherical rutile titanium dioxide mesocrystal prepared in this example is shown in Figure 14. The length of the structural unit nanorod is about 150-200 nm, and the width is about 50-100 nm.

Claims (1)

1. the mesomorphic preparation method of hollow ball-shape rutile titanium dioxide, this titanium dioxide is situated betweenCrystalline substance is the hollow ball-shape structure being assembled by rutile crystallization nanometer rods, the diameter of hollow ballBe 3.0～6.0 μ m, the length of nanometer rods is 200～500nm, and width is 100～250nm,Its preparation comprises that step is as follows:

1) nitric acid of mass concentration 63% is joined in the hydrogen peroxide solution of mass concentration 10%,The volume ratio of nitric acid and hydrogen peroxide solution is 0.02-0.06;

2) to step 1) nitric acid and hydrogen peroxide mixed solution in add titanium potassium oxalate, make oxalic acidThe concentration of titanium potassium in solution is 100～200 mM/ls, and sonic oscillation fully mixes, soRear sealing is incubated 48～72 hours at 80 DEG C, through centrifugation, washing, dry,Mesomorphic to hollow ball-shape rutile titanium dioxide.