CN106186060B - A kind of diameter is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm - Google Patents

Abstract

The invention provides a method for preparing ultrafine hollow titania nanospheres with a diameter of less than 100nm, providing nanocarbon sphere particles as templates; respectively dispersing nanocarbon sphere particles (CSs) templates with different particle sizes in organic solvents to form carbon Spherical sol system, and then add tetra-n-butyl titanate solution diluted with organic solvent drop by drop, react to obtain nano-CSs@TiO ₂ sol with controllable wall thickness and particle size; centrifuge the above CSs@TiO ₂ sol, and the obtained The solid is dried and calcined, and the residue obtained by final calcination is the target product; the method of the present invention realizes a uniform and controllable sphere with complete sphere, good monodispersity, stable storage, particle size below 100nm, and wall thickness within 10nm. Preparation of titanium dioxide hollow nanospheres; the whole preparation process is simple to operate, strong in controllability, good in repeatability, and template materials are widely sourced and cheap in price, low in production cost, safe and environmentally friendly, and suitable for large-scale production.

Description

A preparation method of ultrafine hollow titanium dioxide nanospheres with diameter less than 100nm

technical field

The application belongs to the field of preparation of nanometer microspheres, in particular to a method for preparing ultrafine hollow titanium dioxide nanospheres with a diameter of less than 100 nm.

Background technique

As a nano-semiconductor material with high specific surface area and low density, hollow titanium dioxide nanospheres not only have good permeability, adsorption characteristics, high stability, non-toxicity, transparency, photocatalytic properties, etc., especially in nanometers smaller than 100nm Within the confinement, the ultrafine hollow titanium dioxide nanospheres have obvious quantum effects and surface effects. It not only involves physics, chemistry, materials, biology and other disciplines, but also has a wide range of application value and prospects in optoelectronic devices, molecular detection, biomedicine and catalysis, such as bio-controllable drug delivery, disease diagnosis, micro-nano container , biocapsules, fuel cells, etc. At present, there are many literature reports on the preparation methods of hollow titania nanospheres, and these methods mainly include hard template method, soft template method and non-template method. Among them, the template method is widely used and mature, and its monodispersity of particle size is better, and the template is easy to remove.

In the template method, the soft template method mainly uses microemulsion particles, surfactants, supramolecular micelles, polymer vesicles and even bubbles as templates to prepare titanium dioxide hollow microspheres. Because the shape of the template is difficult to control and unstable, the titanium dioxide hollow microspheres prepared by this method not only have different shapes, but also have poor monodispersity and regularity. At the same time, this preparation process involves a large number of reverse micelles and reverse microspheres Emulsions and solutions pollute the environment, so this method is currently mainly limited to laboratory research and is not suitable for large-scale production applications (Chem.Rev., 2012, 2373; Chem.Soc.Rev., 2011, 5472; J.Phys .Chem.B, 2004, 3492.).

The hard template method is the most direct and effective method for preparing hollow titanium dioxide microspheres, because the prepared hollow nanoparticles have good regularity and the controllability of the whole experiment is good. However, the traditional hard template method mainly uses materials such as polymers as template materials. Not only does a large amount of organic solvents and catalysts be used in the template preparation process, but also the resulting templates often have agglomeration, which needs to be alleviated by adding a large amount of surfactants. In order to make the shell material well coated, these templates often need additional surface activation, and this method is difficult to obtain titanium dioxide hollow nanospheres below 100nm, with good monodispersity and controllable particle size and wall thickness (J. Am. Chem. Soc., 2005, 3928; Chem., 2006, 749; J. Colloid. Interface Sci., 2006, 370; Langmuir., 2001, 3579.).

Contents of the invention

In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing ultrafine hollow titanium dioxide nanospheres with a diameter of less than 100 nm, which are good in monodispersity, stable in storage, and controllable in particle size and wall thickness.

For achieving the above object, the present invention adopts following scheme:

A method for preparing ultrafine hollow titanium dioxide nanospheres with a diameter less than 100nm, comprising the following steps:

s1. Provide nano-carbon sphere templates with a particle size of 20-90nm;

s2. Evenly disperse the nano-carbon sphere template in step s1 in absolute ethanol, and add deionized water to form a nano-carbon sphere sol system. At the same time, place it in a water bath at 60°C with continuous high-speed stirring, and then Add dilute tetra-n-butyl titanate solution diluted with absolute ethanol dropwise, and react for 2-10 hours to obtain CSs@TiO ₂ sol with controllable wall thickness and particle size;

s3. Centrifuge the CSs@TiO ₂ sol obtained in step s2, and dry the separated solid matter, and then perform high-temperature calcination on the block obtained after drying, and heat up to 400 °C at a temperature below 20 °C/min. -800°C, heat preservation time 1-6h, the powder obtained after calcining is the target product, and the particle size of the target product is 20-90nm.

Further, the nano-carbon sphere template is obtained by hydrothermal reaction of glucose as a carbon source.

Further, in the step s2, in the dilute tetra-n-butyl titanate solution, the volume ratio of absolute ethanol to the original solution of tetra-n-butyl titanate is more than 100 times.

Further, during the centrifugation in step s3, the speed is above 20000r/min, and the time is above 10min.

Further, in the step s3, the drying process is carried out in a vacuum oven, the drying temperature is below 60° C., and the drying time is above 6 hours.

Further, the high-temperature calcination atmosphere in step s3 is air.

Further, the wall thickness of the target product titanium dioxide nanospheres is 2-5nm.

The invention discloses a method for preparing ultrafine hollow titanium dioxide nanospheres with a diameter of less than 100 nm, so as to realize hollow titanium dioxide nanospheres with complete spheres, good monodispersity, stable storage, and controllable particle size and wall thickness. At the same time, the conditions of the existing method are optimized. While ensuring the quality of the finished product, try to select the experimental conditions with short reaction time, low raw material prices, and few reaction steps to improve production efficiency and reduce production costs. Problems such as easy agglomeration in carbon spheres are beneficial to large-scale preparation and practical application.

Compared with the prior art, the present invention has the advantages of: the present invention realizes sphere integrity, good monodispersity, stable storage, particle size below 100nm, and wall thickness of 2-5nm at lower temperature and shorter time ultrafine hollow titanium dioxide nanospheres. And the diameter of the nanosphere can be adjusted within 20-90nm. Moreover, the raw material price is low, the preparation time is short, the production efficiency is improved, and the production cost is reduced.

Although the method of the present invention adopts the hard template method, carbon spheres with a particle size of less than 100nm are used as a template. By strictly controlling the experimental parameters and without adding any surfactant and catalyst, the carbon sphere with a particle size of less than 100nm is successfully realized. Preparation of ultrafine hollow titania nanoparticles. An important feature of nanoparticles with a diameter of less than 100nm is that their size is close to or smaller than the mean free path and superconducting coherence wavelength of electrons. Their large specific surface makes the number of atoms and electrons in the surface state comparable to that of atoms and electrons in the interior of the particle. The numbers are comparable. The resulting surface effect and quantum confinement effect make nanoparticles present characteristics that conventional materials do not have in terms of optical properties, electrical properties, mechanical properties, catalytic properties, and biological properties. Therefore, ultrafine hollow titania nanospheres with a diameter of less than 100 nm have broad application prospects in various fields such as optoelectronic technology, biotechnology, and energy technology.

Description of drawings

Fig. 1 is the transmission electron micrograph of ultrafine hollow titania nanosphere obtained in the embodiment 1 of the present invention;

Fig. 2 is the transmission electron micrograph of ultrafine hollow titania nanosphere obtained in the embodiment 2 of the present invention;

Fig. 3 is the transmission electron micrograph of ultrafine hollow titania nanosphere obtained in the embodiment 3 of the present invention;

Detailed ways

The present invention is further illustrated by the following examples: According to the following examples, the present invention can be better understood. However, those skilled in the art can easily understand that the specific material ratios, process conditions and results described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in the claims.

The preparation method of ultrafine hollow titania nanosphere of the present invention, comprises the following steps:

s1. Provide nano-carbon sphere templates with a particle size of 20-90nm;

s2. Uniformly disperse the nano-carbon sphere template described in step s1 in absolute ethanol, and add a certain amount of deionized water to form a nano-carbon sphere sol system. At the same time, place it in a water bath at 60°C with continuous high-speed stirring, and then Under this condition, dilute tetra-n-butyl titanate solution diluted with absolute ethanol was added dropwise, and reacted for more than 2 hours to obtain a CSs@TiO ₂ sol with controllable wall thickness and particle size;

s3. Centrifuge the CSs@TiO ₂ sol obtained in step s2, and dry the separated solid matter, and then perform high-temperature calcination on the dried mass at a heating rate of 20°C/min or less The temperature is 400-800°C, heat preservation in a muffle furnace for 1-6 hours, and the calcination atmosphere is air; the powder obtained after calcination is the target product, and the particle size of the target product is 20-90nm.

Preferably, in the step s1, the preparation process of the nano-carbon sphere template includes: using glucose as a carbon source to perform hydrothermal reaction to obtain nano-carbon spheres.

Preferably, in the step s2, in the dilute tetra-n-butyl titanate solution, the volume ratio of absolute ethanol to the original solution of tetra-n-butyl titanate is more than 100 times.

Preferably, in the step s3, the conditions of the centrifugation treatment include: the speed is above 20000r/min, and the time is above 10min.

Preferably, in the step s3, the drying treatment conditions include: the drying device is a vacuum oven, the drying temperature is below 60° C., and the drying time is above 6 hours.

As one of the preferred specific application schemes, the preparation method of the ultrafine hollow titanium dioxide nanospheres with a diameter less than 100nm specifically includes the following steps:

s1. Taking nano-carbon sphere templates with a particle size of 20-80nm and dispersing them in absolute ethanol to form a nano-carbon sphere sol;

s2. Add the above-mentioned nano-carbon sphere sol into deionized water, and continue vigorously stirring in a water bath at 60°C, then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol, and wait until tetra-n-titanate After all the dilute butyl solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed not lower than 20000r/min for more than 10min to obtain a solid;

s4, placing the above solid in a vacuum oven, and treating it at a temperature not higher than 60°C for more than 6 hours to obtain a dry solid;

s5. Put the above dried solid in a muffle furnace, raise the temperature to 400-800° C. at a heating rate below 20° C./min in an air atmosphere and keep it warm for 1-6 hours to obtain hollow titanium dioxide nanospheres.

The wall thickness of the hollow titanium dioxide nanosphere is 2-5nm.

Example 1

s1. Take 20 mg of nano-carbon sphere template with a particle size of 20-40 nm and disperse it in 60 mL of absolute ethanol to form a nano-carbon sphere sol;

s2. Add 120 μL of deionized water to the above-mentioned nano-carbon sphere sol, and continue vigorously stirring in a water bath at 60° C., and then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol (tetra-n-titanate Dissolve 150 μL of the original solution of butyl titanate in 20 mL of absolute ethanol), after all the dilute tetra-n-butyl titanate solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed of 30000r/min for 15min to obtain a solid;

s4. Put the above solid in a vacuum oven, and treat at 40° C. for 12 hours to obtain a dry solid;

s5. The above dried solid was placed in a muffle furnace, and the temperature was raised to 550° C. at a heating rate of 2° C./min in an air atmosphere and kept for 3 hours to obtain hollow titanium dioxide nanospheres.

Fig. 1 shows the transmission electron microscope photo of the carbon spheres obtained in Example 1, as can be seen from the figure, the diameter of the hollow titanium dioxide nanospheres is 30-40nm, and the wall thickness is about 2nm.

Example 2

s1. Take 20 mg of nano-carbon sphere template with a particle size of 30-60 nm and disperse it in 60 mL of absolute ethanol to form a nano-carbon sphere sol;

s2. Add 120 μL of deionized water to the above-mentioned nano-carbon sphere sol, and continue vigorously stirring in a water bath at 60° C., and then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol (tetra-n-titanate Dissolve 150 μL of the original solution of butyl titanate in 20 mL of absolute ethanol), after all the dilute tetra-n-butyl titanate solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed of 30000r/min for 15min to obtain a solid;

s4. Put the above solid in a vacuum oven, and treat at 40° C. for 12 hours to obtain a dry solid;

s5. The above dried solid was placed in a muffle furnace, and the temperature was raised to 550° C. at a heating rate of 2° C./min in an air atmosphere and kept for 3 hours to obtain hollow titanium dioxide nanospheres.

Figure 2 shows the transmission electron microscope photograph obtained in Example 2, as can be seen from the figure, the diameter of the hollow titanium dioxide nanosphere is 60nm, and the wall thickness is 4nm.

Example 3

s1. Take 20 mg of nano-carbon sphere template with a particle size of 60-90 nm and disperse it in 60 mL of absolute ethanol to form a nano-carbon sphere sol;

s2. Add 120 μL of deionized water to the above-mentioned nano-carbon sphere sol, and continue vigorously stirring in a water bath at 60° C., and then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol (tetra-n-titanate Dissolve 150 μL of the original solution of butyl titanate in 20 mL of absolute ethanol), after all the dilute tetra-n-butyl titanate solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed of 30000r/min for 15min to obtain a solid;

s4. Put the above solid in a vacuum oven, and treat at 40° C. for 12 hours to obtain a dry solid;

s5. The above dried solid was placed in a muffle furnace, and the temperature was raised to 550° C. at a heating rate of 2° C./min in an air atmosphere and kept for 3 hours to obtain hollow titanium dioxide nanospheres.

Fig. 3 shows the transmission electron microscope photo of the carbon spheres obtained in Example 3, as can be seen from the figure, the particle diameter of the hollow titanium dioxide nanospheres is 88nm, and the wall thickness is about 3-5nm.

Example 4

s1. Take 20 mg of nano-carbon sphere template with a particle size of 60-90 nm and disperse it in 60 mL of absolute ethanol to form a nano-carbon sphere sol;

s2. Add 120 μL of deionized water to the above-mentioned nano-carbon sphere sol, and continue vigorously stirring in a water bath at 60° C., and then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol (tetra-n-titanate Dissolve 150 μL of the original solution of butyl titanate in 20 mL of absolute ethanol), after all the dilute tetra-n-butyl titanate solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed of 40000r/min for 10min to obtain a solid;

s4. Put the above solid in a vacuum oven, and treat at 60° C. for 6 hours to obtain a dry solid;

s5. The above dried solid was placed in a muffle furnace, and the temperature was raised to 400° C. at a heating rate of 2° C./min in an air atmosphere and kept at a temperature of 6 hours to obtain hollow titanium dioxide nanospheres.

Example 5

s1. Take 20 mg of nano-carbon sphere template with a particle size of 60-90 nm and disperse it in 60 mL of absolute ethanol to form a nano-carbon sphere sol;

s2. Add 120 μL of deionized water to the above-mentioned nano-carbon sphere sol, and continue vigorously stirring in a water bath at 60° C., and then add dropwise a dilute solution of tetra-n-butyl titanate diluted with absolute ethanol (tetra-n-titanate Dissolve 150 μL of the original solution of butyl titanate in 20 mL of absolute ethanol), after all the dilute tetra-n-butyl titanate solution is added, react for 2-10 hours to obtain a nano-CSs@TiO ₂ sol with controllable particle size and wall thickness;

s3. Centrifuge the above-mentioned nano-CSs@TiO ₂ sol at a centrifugal speed of 30000r/min for 20min to obtain a solid;

s4. Put the above solid in a vacuum oven and treat at 45°C for 10 hours to obtain a dry solid;

s5. Put the above-mentioned dry solid in a muffle furnace, and raise the temperature to 800° C. at a heating rate of 1° C./min in an air atmosphere and hold it for 1 hour to obtain hollow titanium dioxide nanospheres.

The method of the present invention realizes the preparation and particle size control of hollow titania nanospheres with a particle size less than 100nm, and the reaction process does not involve the participation of toxic chemical reagents, which can not only effectively avoid structural defects and environmental pollution caused by the introduction of impurities, but also because of the Hollow titanium dioxide nanospheres are non-toxic and can be widely used in biochemistry and biological diagnosis. The whole preparation process is easy to operate, strong in controllability, good in repeatability, and suitable for industrial production.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. any such actual relationship or order exists between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above description is only the specific implementation of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present application, some improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (5)

1. a kind of diameter is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm, it is characterised in that including following step Suddenly：

S1, provide grain size 20-40nm nano carbon microsphere template；

S2, the nano carbon microsphere template of step s1 is dispersed in absolute ethyl alcohol, and deionized water is added and forms nano carbon microsphere Sol system, while being placed in 60 DEG C of water-bath and accompanying by lasting high-speed stirred, then it is added dropwise under this condition through anhydrous The diluted tetra-n-butyl titanate weak solution of ethyl alcohol, reaction 2-10h obtain the CSs@TiO of wall thickness and size tunable₂Colloidal sol；

The CSs@TiO that s3, centrifugal treating step s2 are obtained₂Colloidal sol, and the solid content isolated is subjected to drying and processing, then Gained block after drying is subjected to high-temperature calcination under air atmosphere, 400-800 DEG C is warming up to 20 DEG C/min or less, when heat preservation Between 1-6h, gained powder is target product after calcining, and the grain size of target product is 20-40nm, and target product titanium dioxide is received The wall thickness of rice ball is 2-5nm.

2. diameter as described in claim 1 is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm, feature exists In：The nano carbon microsphere template is that glucose carries out hydro-thermal reaction acquisition as carbon source.

3. diameter as described in claim 1 is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm, feature exists In：In the step s2, in tetra-n-butyl titanate weak solution, the volume ratio of organic solvent and tetra-n-butyl titanate original solution is 100 times or more.

4. diameter as described in claim 1 is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm, feature exists In：In the step s3 when centrifugal treating, speed is in 20000r/min or more, and the time is in 10min or more.

5. diameter as described in claim 1 is less than the preparation method of the ultra-fine hollow titanium dioxide nano-spheres of 100nm, feature exists In：Drying and processing, drying temperature are 60 DEG C hereinafter, drying time period is 6h or more in vacuum drying oven in the step s3.