CN109867288B

CN109867288B - Mesoporous silica nanobelt material and preparation method thereof

Info

Publication number: CN109867288B
Application number: CN201811086064.2A
Authority: CN
Inventors: 张海娇; 宋亭亭
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2018-09-18
Filing date: 2018-09-18
Publication date: 2022-11-18
Anticipated expiration: 2038-09-18
Also published as: CN109867288A

Abstract

The invention relates to a mesoporous silica nanobelt material and a preparation method thereof. The mesoporous silica nanobelt has a relatively ordered mesoporous channel, the length is 1 to 1.5 mu m, and the width is 45 to 50 nm. As can be seen from SEM pictures, the mesoporous silica nano material prepared by the invention has a unique curled structure. TEM results show that the material edge and the interior are bright and dark, the material edge is also proved to be curled, and an obvious mesoporous channel structure can be observed. The prepared strip-shaped mesoporous silicon oxide nano material has a unique structure with functional modification on the inner surface and the outer surface, and has wide application prospects in the fields of environmental catalysis, adsorption, biomedicine and the like.

Description

Mesoporous silica nanobelt material and preparation method thereof

Technical Field

The invention relates to a mesoporous silica nanobelt material and a preparation method thereof.

Background

Due to the outstanding advantages of high specific area, adjustable aperture, diversified morphology and structure, the mesoporous silica nano material has been widely concerned by the material world and chemists since the first report of MCM-41 by Mobil corporation in 1992, especially in aspects of morphology control, structure regulation, growth mechanism exploration and the like. The mesoporous silicon oxide nano material has a plurality of excellent physicochemical properties, and is related to the unique mesoporous pore canal of the material, and also related to the macroscopic morphology and the microscopic morphology of the material. In recent years, scientists have focused on regulating the internal pore structure of mesoporous silica and also have paid more attention to the rich appearance of mesoporous silica. At present, mesoporous silica nanomaterials with various morphologies and different structures are reported successively, such as spheres, bowls, rods, flowers and the like, and play important roles in the fields of adsorption, catalysis, biomedicine and the like.

It is worth mentioning that, among these structures, the mesoporous silica material having a band-shaped structure attracts particular attention of the researchers due to its unique characteristics such as anisotropy. However, to our knowledge, most of the current researches focus on the preparation of chiral mesoporous silica nanobelts by using chiral surfactants, and the preparation of mesoporous silica nanobelts by using conventional cationic/anionic surfactants as a common template has been rarely reported. The binary surfactant system composed of the cationic surfactant and the anionic surfactant can form various types of microstructures such as vesicles, lamellar structures, spherical structures and rod-shaped structures due to the adjustability of opposite charges of head groups.

Disclosure of Invention

One of the purposes of the invention is to provide a mesoporous silica nanobelt material.

The second purpose of the invention is to provide a preparation method of the mesoporous silica nanobelt.

In order to achieve the purpose, the invention adopts the following technical scheme:

a mesoporous silica nanoribbon material is characterized in that the mesoporous silica nanoribbon has a relatively ordered mesoporous channel, the length is 1 to 1.5 mu m, and the width is 45 to 50 nm.

A method for preparing the mesoporous silica nanobelt material is characterized by comprising the following specific steps:

a. dissolving hexadecyl trimethyl ammonium bromide in deionized water to prepare a solution with the molar concentration of 0.0015 to 0.002 mol/L, then adding Ethyl Acetate (EA), and continuously stirring uniformly; the molar ratio of the ethyl acetate to the hexadecyl trimethyl ammonium bromide is as follows: 6 to 8;

b. b, adding sodium dodecyl sulfate into the solution obtained in the step a, uniformly stirring, adding 25-28 wt.% of ammonia water, and continuously uniformly stirring; the mol ratio of the sodium dodecyl sulfate to the hexadecyl trimethyl ammonium bromide is as follows: 0.9 to 1, and the pH value is between 8 and 10;

c. b, adding tetraethyl orthosilicate serving as a silicon source into the solution obtained in the step b, continuously reacting for 15-24 hours, after the reaction is finished, centrifugally separating the reactant, washing with deionized water, and drying to obtain the mesoporous silica nanobelt material; the molar ratio of tetraethyl orthosilicate to sodium dodecyl sulfate is as follows: 0.4 to 0.5.

The invention takes tetraethyl orthosilicate (TEOS) as a silicon source, adopts an anionic/cationic surfactant as a mixed template, and prepares the mesoporous silica nanobelt material with a unique curled structure together in a guiding way under the action of an assistant template of Ethyl Acetate (EA).

In the synthetic process, the ethyl acetate plays a role in both a cosolvent and a template aid, and a single cationic surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) forms a rod-shaped micelle under a microemulsion system and is assembled to form a sphere with a stable structure. Once the anionic surfactant Sodium Dodecyl Sulfate (SDS) is added, the anion and cation double templates jointly act on the micelle, the formed rod-shaped micelle is longer in length and the number of stacked layers is reduced, so that the stability is reduced, and the structure tends to bend to form a ring structure; when the amount of SDS was further increased to 0.08 g, the stacked rod-like micelles began to collapse to form a lamellar structure, and as the reaction proceeded, the material proceeded in the direction in which the Gibbs free energy decreased, and therefore the surface curled and a curled band-like structure was formed.

Compared with the prior synthesis technology, the technology of the invention has the following remarkable advantages: the two different types of surfactants are used as mixed templates, the synthesis method is simple, the conditions are mild, the morphology is controllable, and the unique curled nano-structure has potential application prospects in the fields of environmental catalysis, adsorption, biomedicine and the like.

Drawings

Fig. 1 is an SEM picture of the mesoporous silica nanobelt obtained in example 1 of the present invention.

FIG. 2 is a TEM image of the mesoporous silica nanoribbon obtained in example 1 of the present invention.

FIG. 3 is a TEM image of the mesoporous silica nanorods obtained in example 2 of the present invention.

FIG. 4 is a TEM photograph of mesoporous silica nanospheres obtained in comparative example of the present invention.

Detailed Description

All the embodiments are operated according to the operation steps of the technical scheme.

Example 1

a. 0.1 g cetyltrimethylammonium bromide (CTAB) was dissolved in 137 mL deionized water until the solution was clear, then 1.32 mL Ethyl Acetate (EA) was added and stirring continued;

b. adding 0.08 g of Sodium Dodecyl Sulfate (SDS) into the solution, wherein the molar ratio of the Sodium Dodecyl Sulfate (SDS) to CTAB is 1, uniformly stirring, adding 2.7 mL of ammonia water (25 to 28 wt.%), and continuously uniformly stirring;

c. and finally, 275 mu L of tetraethyl orthosilicate (TEOS) is added to serve as a silicon source, the reaction is continued for 20 hours, after the reaction is completed, the reactant is centrifugally separated, and is repeatedly washed by deionized water and dried, so that the obtained white powder is the mesoporous silica nanobelt.

The obtained product is subjected to physical property characterization, and part of results are shown in the attached figures. The length of the obtained mesoporous silicon oxide product is 1 to 1.5 mu m, the width is about 45 nm, and the product is in a strip-shaped structure with a curled edge. Meanwhile, TEM results show that the material has obvious mesoporous channels along the radial direction of the belt-shaped structure and uniform appearance.

Example 2

The procedure and steps of this example were substantially the same as in example 1 except that the b step:

sodium Dodecyl Sulfate (SDS) was used in an amount of 0.04 g.

The obtained result is obviously different from the product obtained in the embodiment 1 in the aspects of appearance and structure, the obtained product part presents a closed annular structure, the structure mainly comprises nanorods with the length of about 400 nm and the diameter of about 43 nm, and the product has good pore channel characteristics.

Example 3

The procedure and steps of this example were substantially the same as in example 1 except that step a:

ethyl Acetate (EA) was used in an amount of 0.5 mL.

The results obtained are clearly different from those of example 1, giving a product with a lamellar structure, with slightly curled edges, but relatively thick and with poor dispersibility.

Example 4

ethyl Acetate (EA) was replaced with an equal volume of diethyl ether.

The results obtained are clearly different from those of example 1, giving a rod-like structure folded in a coil.

Comparative example: the procedure and steps of this example are exactly the same as in example 1, except that step b:

sodium Dodecyl Sulfate (SDS) was not added.

The obtained result has larger shape difference with the embodiment 1, and the mesoporous silica nanospheres with uniform shape are obtained after the reaction is finished, the monodispersity is good, and the particle size is 150 to 200 nm.

Referring to the drawings, fig. 1 is a Scanning Electron Microscope (SEM) picture of the mesoporous silica nanobelt material obtained in example 1 of the present invention. SEM analysis: the morphology of the material was observed using a JSM-6700F model emission scanning electron microscope, japan Electron Co. As can be seen from SEM pictures, the mesoporous silicon oxide material prepared by the method has uniform appearance and unique curled nano-structure.

Referring to the accompanying drawings, fig. 2 is a Transmission Electron Microscope (TEM) image of the mesoporous silica nanobelt material obtained in example 1 of the present invention. TEM analysis: the morphology and structure of the material were observed by a JEOL-200CX type transmission electron microscope, japan Electron Co. As can be seen from TEM pictures, the mesoporous silica material prepared by the method has an obvious belt-shaped structure and mesoporous channels, the width of the mesoporous silica material is 45-50 nm, the thickness of a sheet layer is about 5 nm, and the length of the mesoporous silica material is 1-1.5 mu m.

Referring to the accompanying drawings, fig. 3 is a Transmission Electron Microscope (TEM) image of the mesoporous silica nanorod material obtained in example 2 of the present invention. It can be seen that the mesoporous silica prepared in this example has a rod-connected rhombohedral structure, and the diameter of the rod is about 43 nm.

Referring to the accompanying drawings, fig. 4 is a Transmission Electron Microscope (TEM) image of mesoporous silica nanospheres obtained in comparative examples of the present invention. According to TEM pictures, the silicon oxide nano-material prepared by the comparative example has uniform spherical morphology, relatively ordered mesopores and good monodispersity, and the particle size of the silicon oxide nano-material is 150-200 nm.

Claims

1. A preparation method of a mesoporous silica nanobelt material is characterized by comprising the following specific steps:

a. dissolving cetyl trimethyl ammonium bromide in deionized water to prepare a solution with the molar concentration of 0.0015 to 0.002 mol/L, then adding Ethyl Acetate (EA), and continuously stirring uniformly; the molar ratio of the ethyl acetate to the hexadecyl trimethyl ammonium bromide is as follows: 6 to 8;

b. b, adding sodium dodecyl sulfate into the solution obtained in the step a, uniformly stirring, adding 25-28 wt.% of ammonia water, and continuously uniformly stirring; the mol ratio of the sodium dodecyl sulfate to the cetyl trimethyl ammonium bromide is as follows: 0.9 to 1, and the pH value is between 8 and 10;

c. adding tetraethyl orthosilicate serving as a silicon source into the solution obtained in the step b, continuously reacting for 15-24 hours, after the reaction is finished, centrifugally separating the reactant, washing with deionized water, and drying to obtain a mesoporous silica nanobelt material, wherein the mesoporous silica nanobelt material is provided with relatively ordered mesoporous channels, the length is 1-1.5 mu m, and the width is 45-50 nm;

the molar ratio of tetraethyl orthosilicate to sodium dodecyl sulfate is as follows: 0.4 to 0.5.