CN112429742B

CN112429742B - Silicon dioxide nano particle with nano stick and nano ball and preparation method thereof

Info

Publication number: CN112429742B
Application number: CN202011378566.XA
Authority: CN
Inventors: 于锋; 陈强; 郭爱霞; 邓海珊
Original assignee: Shihezi University
Current assignee: Shihezi University
Priority date: 2020-11-30
Filing date: 2020-11-30
Publication date: 2023-06-23
Anticipated expiration: 2040-11-30
Also published as: CN112429742A

Abstract

The invention relates to a silicon dioxide nanoparticle with a nanorod and a nanosphere and a preparation method thereof. A method for preparing silica nanoparticles having nanorods and nanospheres, comprising: (1) Adding ethyl orthosilicate into an ethanol solution to obtain a precursor solution A; sequentially adding water and ammonia water into hexadecyl trimethyl ammonium bromide, and stirring to obtain a precursor solution B; (2) Absorbing the precursor liquid A, B in an equivalent amount, and rapidly pushing the solution into a reaction die for mixing to obtain a microemulsion; (3) Stirring the microemulsion to colloid state under the water bath condition to obtain a silicon dioxide colloid solution; (4) Adding methanol into the silicon dioxide colloid solution, heating under reflux, and aging to obtain suspension; (5) And filtering and drying the suspension to obtain the silica nano particles. According to the technical scheme, the silica nanoparticle with the nanorods and nanospheres can be prepared, the morphology of the silica nanoparticle is similar to that of a gourd-shaped silica nanoparticle, and the silica nanoparticle has an ultrahigh specific surface area.

Description

Silicon dioxide nano particle with nano stick and nano ball and preparation method thereof

Technical Field

The invention belongs to the technical field of inorganic nano materials, and particularly relates to a silicon dioxide nanoparticle with a nano rod and a nano sphere and a preparation method thereof.

Background

Silica has good mechanical strength, thermal stability and chemical inertness and has long played an extremely important role in the scientific research and industrial technical fields. Porous SiO due to three-dimensional hierarchical structure ₂ The microsphere has larger specific surface area and richer pore volume and pore diameter, and has wide application in the fields of catalysis, adsorption, material auxiliaries and the like.

Silica nanorods and silica nanospheres are the most common nanomaterial. The lateral dimension and the longitudinal dimension of the silica nanorods are different, and the nanorods have additional orientation entropy and excellent spatial stability. The silica nanospheres have a higher specific surface, richer pore channel structure and more uniform morphology due to the unique physical structure.

In the application aspect of materials, the photoelectric characteristics can be optimized by changing the diameter and the length of the nano rod; in medicine, the copolymer of nanospheres and nanorods can be used to fabricate highly sensitive surface-enhanced raman scattering and plasma nanodevices, etc. These functions are based on the ordered orientation of the nanorods and the high specific surface area of the nanospheres. It is therefore a critical issue how to design nanoparticles with both nanorods and nanospheres.

In view of this, the present invention provides a new method for preparing silica nanoparticles, which can prepare gourd-shaped silica nanoparticles with ultra-high specific surface area, so that one end of each nanoparticle is spherical, and the other end is rod-shaped, and the nanoparticle has the ultra-high specific surface area of the nanoparticle and the ordered orientation of the nanorods.

Disclosure of Invention

The invention aims to provide a preparation method of silica nanoparticles with nanorods and nanospheres, which can prepare silica nanoparticles with nanorods and nanospheres simultaneously, and fills the gap of the silica nanoparticles with nanorods and nanospheres simultaneously in the prior art.

In order to achieve the above purpose, the technical scheme adopted is as follows:

a method for preparing silica nanoparticles having nanorods and nanospheres, comprising the steps of:

(1) Preparing a precursor solution:

adding ethyl orthosilicate into an ethanol solution to obtain a precursor solution A;

adding water into hexadecyl trimethyl ammonium bromide for dissolution, then adding ammonia water, and stirring to obtain a precursor solution B;

(2) Preparing a microemulsion: the precursor liquid A, B is sucked in an equivalent way, placed on a microinjection pump, and rapidly pushed into a reaction mold for mixing at the same injection speed to obtain microemulsion containing tetraethoxysilane;

(3) Preparing a silica colloid solution: stirring the microemulsion to colloid state under the condition of low-temperature water bath to obtain a silicon dioxide colloid solution;

(4) Adding methanol into the silicon dioxide colloid solution, heating under reflux, and aging for 12 hours to obtain a suspension containing silicon dioxide nanosphere particles;

(5) And (3) carrying out suction filtration and drying on the suspension to obtain the silica nanoparticle with the nanorods and nanospheres.

Further, in the precursor solution A, the volume ratio of the tetraethoxysilane to the ethanol solution is 1-5:500;

the volume of ethanol and water in the ethanol solution is 1:1-2.

Further, in the precursor solution B, the proportion of hexadecyl trimethyl ammonium bromide, water and ammonia water is 0.72-5.76g:450ml:8-30ml.

Further, in the preparation of the precursor solution B, stirring is carried out for 40min at 25-40 ℃.

Further, in the step (2), the injection speed is less than 38ml/min.

Further, in the step (3), the temperature of the low-temperature water bath is 5-10 ℃, and the stirring time is not less than 3 hours.

Further, in the step (4), the volume ratio of the methanol to the silica colloid solution is 1-8:10;

the reflux temperature is 68-80 ℃ and the aging temperature is 0-5 ℃.

Further, in the step (5), the drying temperature is 120 ℃.

The invention also aims to provide the silica nanoparticle with the nanospheres and the nanospheres, which is prepared by adopting the preparation method, has the appearance similar to a gourd-shaped shape, has the ultrahigh specific surface area, has one end of the nanoparticle in a spherical shape and the other end in a rod shape, and has the ultrahigh specific surface area of the nanospheres and the ordered orientation of the nanospheres.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the technical scheme, the silicon dioxide nano particles with the nano rods and the nano spheres can be prepared.

2. According to the technical scheme, the template agent is not required to be removed by high-temperature roasting, so that the cost is saved.

3. The silica nanoparticle prepared by the invention is in a gourd shape, namely, one end of the nanoparticle is spherical, and the other end of the nanoparticle is in a stick shape, and has the ultrahigh specific surface area of the nanosphere and the ordered orientation of the nanorods, so that the nanoparticle has the ultrahigh specific surface area and can be applied to the fields of catalytic carriers, stabilizers, reinforcing agents, additives, adsorbents, optoelectronics, biology and the like.

Drawings

FIG. 1 is a TEM image of silica nanoparticles prepared according to example 1 of the present invention;

FIG. 2 is a graph showing the desorption of nitrogen from silica nanoparticles prepared in example 1 of the present invention;

FIG. 3 is a graph showing pore size distribution of silica nanoparticles prepared in example 1 of the present invention;

FIG. 4 is a TEM image of silica nanoparticles prepared in example 2;

FIG. 5 is a HRTEM image of silica nanoparticles prepared in example 3;

FIG. 6 is a TEM image of silica nanoparticles prepared in example 4;

FIG. 7 is a TEM image of silica nanoparticles prepared in example 5;

FIG. 8 is a TEM image of silica nanoparticles prepared in example 6;

FIG. 9 is an SEM image of silica nanoparticles prepared according to example 7;

FIG. 10 is a TEM image of silica nanoparticles prepared in example 9;

FIG. 11 is an SEM image of silica nanoparticles prepared according to example 10;

FIG. 12 is a TEM image of silica nanoparticles prepared in example 12;

FIG. 13 is an SEM image of silica nanoparticles prepared according to example 13;

FIG. 14 is a TEM image of silica nanoparticles prepared in example 14;

fig. 15 is an SEM image of silica nanoparticles prepared in example 15.

Detailed Description

In order to further illustrate a silica nanoparticle having nanorods and nanospheres and a method for preparing the same according to the present invention, the following describes a silica nanoparticle having nanorods and nanospheres and a method for preparing the same according to the present invention, and specific embodiments, structures, features and effects thereof will be described in detail. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, the particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

The following describes in further detail a silica nanoparticle with nanorods and nanospheres and a method for preparing the same according to the present invention, with reference to specific examples:

the invention prepares the surfactant into a solution with the concentration larger than CMC (critical micelle concentration) to form a spherical liquid crystal template, the surfactant is hedging into a coexisting liquid crystal template system of big spheres and small spheres by controlling the speed of a mixed force field, and the big spheres and the small spheres are formed into nanospheres by the hydrolysis of tetraethoxysilane. Finally, the repulsive force of the big ball and the small ball is broken through heating reflux, and the big ball and the small ball are connected through the structural guidance of the surfactant to form the gourd-shaped silicon dioxide nano-particles. The technical scheme of the invention is as follows:

(1) Preparing a precursor solution:

Preferably, in the precursor solution A, the volume ratio of the tetraethoxysilane to the ethanol solution is 1-5:500;

the volume of ethanol and water in the ethanol solution is 1:1-2. The amount of ethanol affects the sphericity of the nanoparticle and if not good, the morphology of the final silica nanoparticle. The amount of ethyl orthosilicate affects the particle size of the nanoball, thereby affecting the formation of the nanorod segment,

preferably, in the precursor solution B, the ratio of hexadecyl trimethyl ammonium bromide, water and ammonia water is 0.72-5.76g:450ml:8-30ml. The amount of cetyltrimethylammonium bromide has an effect on the particle size of the nanoparticle.

Preferably, the precursor solution B is stirred at 25-40 ℃ for 40min. At this temperature, complete dissolution of cetyltrimethylammonium bromide in water is ensured.

Preferably, in the step (2), the injection speed is less than 38ml/min.

Preferably, in the step (3), the temperature of the low-temperature water bath is 5-10 ℃, and the stirring time is not less than 3 hours.

Preferably, in the step (4), the volume ratio of methanol to the silica colloid solution is 1-8:10. Methanol can be replaced with any of the alcohols and ketones for demulsification.

The reflux temperature is 68-80 ℃ and the aging temperature is 0-5 ℃.

Preferably, in the step (5), the drying temperature is 120 ℃.

Example 1.

The specific operation steps are as follows:

(1) Preparing a precursor solution:

adding ethyl orthosilicate into an ethanol water solution (the volume ratio of ethanol to water in the ethanol solution is 1:1), stirring for 2 hours, and obtaining a precursor solution A, wherein the volume ratio of the ethyl orthosilicate to the ethanol solution is 2:500.

450ml of water and 10ml of ammonia water were added to 0.77g of cetyltrimethylammonium bromide in this order, and the mixture was stirred at 35℃for 2 hours to obtain a precursor solution B.

(2) Preparing microemulsion containing tetraethoxysilane:

respectively sucking the precursor liquid A, B in equal quantity by using a syringe, and placing the precursor liquid A, B on a microinjection pump; the two solutions were rapidly pushed into the reaction mold and rapidly mixed at the same injection rate of 25ml/min to obtain a microemulsion containing ethyl orthosilicate.

(3) Preparing a silica colloid solution:

the microemulsion containing the tetraethoxysilane is put into a low-temperature water bath kettle with the temperature of 8 ℃ and stirred for 3 hours, so as to obtain the silicon dioxide colloid solution.

(4) Adding methanol into the silicon dioxide colloid solution, wherein the volume ratio of the methanol to the silicon dioxide colloid solution is 1:9, refluxing for 30min at 68 ℃, and aging for 12h in a refrigerator at 5 ℃ to obtain a suspension containing silicon dioxide nanosphere particles;

(5) And (3) carrying out suction filtration on the particle suspension, and drying at 120 ℃ to obtain the gourd-shaped silica nanospheres with ultra-high specific surface areas.

FIGS. 1 to 3 are TEM, nitrogen adsorption drawing and pore size distribution diagrams of a gourd-shaped silica nanoparticle with ultra-high specific surface area prepared in example 1 of the present invention.

As can be seen from FIG. 1, the silica nanospheres with a gourd-like morphology, which are prepared by the embodiment of the invention, have nanorods and nanospheres. The spherical particle size was determined to be 220nm.

As can be seen from FIG. 2, the specific surface area of the prepared silica nanospheres is 1644.34m ² And/g, the specific surface area is ultrahigh.

As can be seen from FIG. 3, the average pore diameter of the prepared silica nanospheres is 2-3nm.

The invention can rapidly prepare the silicon dioxide nano particles with the gourd-shaped appearance by adopting the microchannel reactor, and the nano particles are provided with nano rods and nano spheres, and have ultrahigh specific surface area. According to the technical scheme, the preparation of the specific surface area and the particle size can be regulated, and the method can be used for rapidly preparing the silicon dioxide nano-particles of the gourd, so that the silicon dioxide nano-particles have the ultra-high specific surface area of the nano-microsphere and the space orientation of the nano-rod.

Example 2.

The procedure of example 2 was the same as that of example 1, except that step (2) was conducted to prepare a microemulsion containing ethyl orthosilicate.

(2) Preparing microemulsion containing tetraethoxysilane:

and slowly dripping the precursor solution A into the precursor solution B at the mechanical stirring speed of 500rmp/min by taking the precursor solution B as a base solution, and then continuously stirring for 30min.

TEM characterization was performed on the silica nanoparticles prepared in example 2. As shown in fig. 4, it can be seen from fig. 4 that the silica spheres have poor sphere forming effect, and the gourd-shaped silica nanospheres cannot be obtained, and some of the silica nanospheres cannot be formed into spheres.

Example 3.

The procedure of example 3 was identical to that of example 1, except for step (2), at an injection rate of 40ml/min.

HRTEM characterization was performed on silica nanoparticles prepared in example 3, as shown in fig. 5. As can be seen from FIG. 5, only spherical silica was formed at an injection rate of 40ml/min.

Example 4.

The procedure of example 4 was identical to that of example 1, except for step (2), at an injection rate of 15ml/min.

The silica nanoparticles prepared in example 4 were subjected to TEM characterization as shown in fig. 6. As can be seen from FIG. 6, the silica nanospheres with a gourd-like morphology were prepared, with nanorods and nanospheres. And the rod-shaped portion of the formed silica was longer than that of the silica prepared in example 1.

Example 5.

The procedure of example 5 was identical to that of example 1, except that:

in the step (1), the dosage of the hexadecyl trimethyl ammonium bromide is 4.40g;

in the step (2), the injection speed was 35ml/min.

The silica nanoparticles prepared in example 5 were subjected to TEM characterization as shown in fig. 7. As can be seen from FIG. 7, the silica nanospheres with a gourd-like morphology were prepared, with nanorods and nanospheres. And the rod-shaped portion was shortened and thinned as compared with the silica prepared in example 1.

Example 6.

The procedure of example 6 was identical to that of example 1, except that:

in the step (2), the injection speed was 38ml/min.

The silica nanoparticles prepared in example 6 were subjected to TEM characterization as shown in fig. 8. As can be seen from fig. 8, the prepared silica gradually becomes like a water drop.

Example 7.

The procedure of example 7 was identical to that of example 1, except that:

in the step (1), cetyltrimethylammonium bromide was used in an amount of 7.2g.

SEM characterization was performed on the silica nanoparticles prepared in example 5, as shown in fig. 9. As can be seen from FIG. 9, the prepared silica was severely agglomerated.

Example 8.

The procedure of example 8 was identical to that of example 1, except that:

in the step (1), the dosage of the cetyl trimethyl ammonium bromide is less than 0.72g. However, when the amount of cetyltrimethylammonium bromide is less than 0.72g, silica cannot be formed.

Example 9.

The procedure of example 9 was identical to that of example 1, except that:

in step (1), cetyltrimethylammonium bromide was used in an amount of 3.08g.

The silica nanoparticles prepared in example 9 were subjected to TEM characterization as shown in fig. 10. As can be seen from fig. 10, the silica nanospheres with a gourd-like morphology were prepared, having nanorods and nanospheres, with the rod-shaped portion being inclined so as not to be perpendicular to the center of the sphere.

Example 10.

The procedure of example 10 was the same as that of example 1, except that in the preparation of precursor liquid a in step (1): the ratio of ethanol to water in the ethanol aqueous solution is 0:1.

SEM characterization was performed on the silica nanoparticles prepared in example 10, as shown in fig. 11. As can be seen from FIG. 11, the hydrolysis reaction of TEOS is accelerated, the sphericity is reduced, the silica balling effect is poor, the silica is easy to agglomerate, and the gourd-shaped silica nanospheres cannot be obtained.

Example 11.

The procedure of example 11 was the same as that of example 1, except that in the preparation of precursor liquid a in step (1): when the ratio of ethanol to water in the ethanol aqueous solution is 1:0, the reaction cannot be performed.

Example 12.

The procedure of example 12 is the same as that of example 1, except that in the preparation of precursor liquid a in step (1): the ratio of ethanol to water in the ethanol aqueous solution is 1:3.

The silica nanoparticles prepared in example 12 were subjected to TEM characterization as shown in fig. 12. As can be seen from fig. 12, the regularity of the balls is significantly reduced.

The amount of ethanol mainly influences the reaction speed, for example, if the ratio of ethanol to water is 1:0, the reaction cannot be carried out, and the influence condition is the same as that of an aqueous solution, and the more the aqueous solution is, the faster the reaction is.

Example 13.

The procedure of example 13 is the same as that of example 1, except that in the preparation of precursor liquid a in step (1): the volume ratio of the tetraethoxysilane to the ethanol solution is 1:500.

SEM characterization was performed on the silica nanoparticles prepared in example 13, as shown in fig. 13. As can be seen from fig. 13, the silica nanospheres with a gourd-like morphology are prepared, and have nanorods and nanospheres; and the spherical particle diameter is 180nm, and the particle diameter becomes irregular.

As can be seen from comparison with the silica nanospheres prepared in example 1, the spherical particle size was increased when the amount of ethyl orthosilicate was increased.

Example 14.

The procedure of example 14 was the same as that of example 1, except that in the preparation of precursor liquid a in step (1): the volume ratio of the tetraethoxysilane to the ethanol solution is 8:500.

The silica nanoparticles prepared in example 14 were subjected to TEM characterization as shown in fig. 14. As is clear from FIG. 14, when the amount of ethyl orthosilicate is increased, the stick portion gradually merges into the large ball, and the ball becomes nonuniform in size.

Example 15.

The procedure of example 15 was the same as that of example 1, except that in the preparation of precursor liquid a in step (1): the volume ratio of the tetraethoxysilane to the ethanol solution is 6:500.

SEM characterization was performed on the silica nanoparticles prepared in example 15, as shown in fig. 15. As can be seen from fig. 15, the stick portion gradually becomes small balls, which are dispersed around the large balls.

Example 16.

The procedure of example 16 was the same as that of example 1, except that in the preparation of precursor liquid B in step (1): the volume ratio of water to ammonia water is 450ml:8ml.

Through detection, the silicon dioxide nanospheres similar to the gourd appearance can be formed, and the silicon dioxide nanospheres are provided with nano sticks and nanospheres.

Example 17.

The procedure of example 17 was the same as that of example 1, except that in the preparation of precursor liquid B in step (1): the volume ratio of water to ammonia water is 450ml:30ml.

The foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the embodiment of the present invention in any way, but any simple modification, equivalent variation and modification of the above embodiment according to the technical substance of the embodiment of the present invention still fall within the scope of the technical solution of the embodiment of the present invention.

Claims

1. A method for preparing silica nanoparticles having nanorods and nanospheres, comprising the steps of:

(1) Preparing a precursor solution:

adding ethyl orthosilicate into an ethanol solution to obtain a precursor solution A; in the precursor solution A, the volume ratio of the tetraethoxysilane to the ethanol solution is 1-5:500; the volume of ethanol and water in the ethanol solution is 1:1-2;

adding water into hexadecyl trimethyl ammonium bromide for dissolution, then adding ammonia water, and stirring to obtain a precursor solution B; in the precursor solution B, the proportion of hexadecyl trimethyl ammonium bromide, water and ammonia water is 0.72-5.76g:450ml:8-30ml;

(2) Preparing a microemulsion: the precursor liquid A, B is sucked in an equivalent way, placed on a microinjection pump, and rapidly pushed into a reaction mold for mixing at the same injection speed to obtain microemulsion containing tetraethoxysilane; the injection speed is less than 38ml/min;

2. The method according to claim 1, wherein,

in the preparation of the precursor solution B, stirring is carried out for 40min at 25-40 ℃.

3. The method according to claim 1, wherein,

in the step (3), the temperature of the low-temperature water bath is 5-10 ℃, and the stirring time is not less than 3 hours.

4. The method according to claim 1, wherein,

in the step (4), the volume ratio of the methanol to the silicon dioxide colloid solution is 1-8:10;

the reflux temperature is 68-80 ℃ and the aging temperature is 0-5 ℃.

5. The method according to claim 1, wherein,

in the step (5), the drying temperature is 120 ℃.

6. A silica nanoparticle having nanorods and nanospheres, characterized in that it is prepared by the method of any one of claims 1 to 5.