CN100410171C

CN100410171C - Method for synthesizing silicon oxide thin sheet with three dimension continuous nano pore structure

Info

Publication number: CN100410171C
Application number: CNB2005100239193A
Authority: CN
Inventors: 山巍; 王波; 唐颐
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2005-02-06
Filing date: 2005-02-06
Publication date: 2008-08-13
Anticipated expiration: 2025-02-06
Also published as: CN1683241A

Abstract

The present invention relates to a method for synthesizing a silicon oxide sheet with a three-dimensional continuous nanometer pore canal structure. The existing silicon oxide class sheet material mainly comprises layered silicate and layered mesopore silicon oxide. But because the layered plates of the materials are all closed commonly, guest molecules only can diffuse into the material via the gaps of the layered plates. In the method, silicon grease is utilized as a silicon resource, and long chain alkyl primary amine is utilized as a template agent. A silicon oxide sheet with a three-dimensional continuous nanometer pore canal structure is synthesized in alcohol/water mixed solvent under the condition of a normal temperature. Meanwhile, the thickness of the sheet can be controlled within the range between a nanometer level to a submicron level by adjusting the proportion of a reactant. The preparation method has the advantages of simple and convenient operation and low cost. Because the surface of the silicon oxide sheet is provided with abundant pore openings which are very favorable for the diffusion of the guest molecules, the silicon oxide sheet can be used as an adsorbent carrier or a catalyst carrier.

Description

A kind of synthetic method of three dimension continuous nano pore structure silicon oxide flakes that has

Technical field

The present invention is a kind of synthetic method of three dimension continuous nano pore structure silicon oxide flakes that has.

Background technology

The nanoporous silica material has great application prospect in catalysis and adsorbing domain owing to its abundant pore passage structure and huge specific surface area.In recent years, people recognize that more and more except the aperture and the pore passage structure of nanoporous silicon oxide itself, its microscopic appearance has also influenced its actual performance to a great extent.One of them very important aspect is exactly that size control with product is at submicron order or nano level.The nanoparticle and the nanofiber of nanoporous silicon oxide are synthesized by the whole bag of tricks in succession.But because the size of these materials is too little, the operation in synthetic and application process is all very inconvenient.By contrast, two-dimensional nano hole material just has remarkable advantages.It has the advantage of nanoparticle and nanofiber, and promptly diffusion path is lacked and bigger external surface area, and its operation wants ratio nano particle and nanofiber to make things convenient for manyly.The flake oxidized silicon of existing two-dimensional hole material mainly comprises traditional layered silicate and mesopore stratiform silicon oxide at present.But generally all do not have pore structure on the laminate of these materials, guest molecule can only diffuse into material internal from interlamellar spaces, and some material structure after roasting can cave in, thereby has limited the application of these materials in catalysis and absorption.

Since orderly mesopore silicon oxide in 1992 was synthesized first, various surfactants was applied to synthetic mesopore silicon oxide in succession.Nineteen ninety-five, people such as Pinnavaia adopt long chain alkyl primary amine as template first, are the silicon source with the tetraethoxy, have synthesized to have the three-dimensional mesopore silicon oxide of pore passage structure continuously.And this product is as support applications the time, and performance will obviously be better than traditional MCM-41 mesopore silicon oxide.But since the surfactivity ability of long chain alkyl primary amine a little less than, and be insoluble in water, the work of the morphology control aspect of product is not ideal always.If so can keep its three-dimensional pore passage structure continuously, again it is prepared into the two-dimensional slice material simultaneously, in catalysis and absorption, all good prospects for application will be arranged.

Summary of the invention

The objective of the invention is to obtain the simple and direct easy control of a kind of method, the product pattern is good, structure properties stable, thickness is adjustable method with three dimension continuous nano pore structure silicon oxide flakes.

Synthetic method with three dimension continuous nano pore structure silicon oxide flakes involved in the present invention is as follows:

1. a certain amount of long chain alkyl primary amine is dissolved in alcohol, adds a certain amount of water and strong aqua then, stirring is dissolved the long chain alkyl primary amine of separating out again;

2. take by weighing a certain amount of methyl silicate or tetraethoxy, add the alcohol/aqueous solution of the long chain alkyl primary amine of vigorous stirring, stop after continuing to be stirred to methyl silicate or tetraethoxy homodisperse, place certain hour at a certain temperature;

3. will get product after product suction filtration, washing, drying and the high-temperature roasting.

Said long chain alkyl primary amine such as cetylamine, stearylamine etc. have the primary amine of chain alkyl structure in above-mentioned 1, pure or these pure mixtures that alcohol as methyl alcohol, ethanol, n-propyl alcohol, Virahol etc. can infinitely dissolve each other with water.The consumption of long chain alkyl primary amine is every liter of solvent 1.5～5.5 grams, and the volume ratio of alcohol and water is 0.9～1.4, and strong aqua is the ammoniacal liquor of commercially available 35-38wt%, and its consumption is every liter of solvent 10～40 grams.

Said tetraethoxy, methyl silicate are the Esters of energy hydrolysis becoming silicon oxide in 2.The consumption of methyl silicate or tetraethoxy is every liter of solvent 5～30 grams.Synthesis temperature is a normal temperature, and generated time is 4-24 hour.

Said maturing temperature can be 500～650 ℃ in 3, and roasting time can be 2～10 hours.

Better condition of the present invention is:

Long chain alkyl primary amine is cetylamine or stearylamine.

Used alcohol is any or their alcohol mixture in methyl alcohol, ethanol, n-propyl alcohol, the Virahol.

The consumption of long chain alkyl primary amine is every liter of solvent 3.0～5.0 grams, and the volume ratio of alcohol and water is 1.0～1.2, and the consumption of ammoniacal liquor is every liter of solvent 20～30 grams.The consumption of methyl silicate or tetraethoxy is every liter of solvent 15～25 grams.

Synthesis temperature is 10～35 ℃, and generated time is 12～24 hours.

Maturing temperature is 550～600 ℃, and roasting time is 4～6 hours.

Above-mentioned condition had both improved preparation efficiency, had guaranteed quality product again.

The silicon oxide flakes thickness that the inventive method obtains can be regulated by the add-on of control long chain alkyl primary amine and methyl silicate or tetraethoxy, generally can be in the 5-500nm scope.

The silicon oxide flakes that the inventive method obtains has extensive use at sorbent material or support of the catalyst field.

The three dimension continuous nano pore structure silicon oxide flakes that has that the present invention can prepare has abundant nano-pore structure, and material has one dimension at nano level or submicron order, traditional relatively pattern product has big external surface area and short diffusion path, can improve the velocity of diffusion of reactant and product in catalyzed reaction.The thickness of silicon oxide flakes can be regulated by the amount that adds methyl silicate or tetraethoxy and long chain alkyl primary amine.The simple and direct easy control of the inventive method is fit to the industrialization demand, and product structure is stable, functional, at absorption, catalytic field the applications well prospect is arranged.

Description of drawings

Fig. 1 is a product A ₁Sem photograph (scale is 5 microns).

Fig. 2 is a product A ₁Transmission electron microscope picture (scale is 1 micron, and the scale of insertion figure is 20 nanometers).

Fig. 3 is a product A ₁Nitrogen adsorption curve figure.

Embodiment

Below example be to synthetic the further specifying that the three dimension continuous nano pore structure silicon oxide flakes done that have provided by the present invention.

Example 1

Take by weighing 0.6 gram cetylamine and be dissolved in 60 milliliters of ethanol, add 60 ml waters and 2.0 gram strong aquas, be stirred to cetylamine and dissolve fully.Under the vigorous stirring, add 2.4 gram tetraethoxys, continue to be stirred to the tetraethoxy homodisperse.After stopping to stir, placed 12 hours in room temperature, suction filtration is used washing with alcohol, 90 ℃ of dried overnight.Template was removed in roasting in 4 hours under 600 ℃ of air atmospheres at last.Product is designated as A ₁

Example 2～6

It is synthetic to press example 1 described method, but the add-on of tetraethoxy is changed into 0.6,1.2,1.8,3.0 and 3.6 grams, and the proportioning and the reaction conditions of other reactant all do not change.The product that makes is designated as A ₂, A ₃, A ₄, A ₅And A ₆

Example 7～10

It is synthetic to press example 1 described method, but the add-on of cetylamine is changed into 0.2,0.3,0.4 and 0.5 gram, and the proportioning and the reaction conditions of other reactant all do not change.The product that makes is designated as A ₇, A ₈, A ₉And A ₁₀

In Philips XL30 scanning electronic microscope and JEOL-2010 transmission electron microscope photographs, acceleration voltage is respectively 20kV and 200kV respectively for scanning electron microscope and transmission electron microscope photo.The nitrogen adsorption curve is measured on ASAP-2000 type physical adsorption appearance.

The mean thickness of the silicon oxide flakes product that above-mentioned example obtains is as follows:

Numbering	A ₁	A ₂	A ₃	A ₄	A ₅
Numbering	A ₁	A ₂	A ₃	A ₄	A ₅	Thickness (nanometer)	200	100	120	150	320
Numbering	A ₆	A ₇	A ₈	A ₉	A ₁₀	Thickness (nanometer)	200	100	120	150	320
Numbering	A ₆	A ₇	A ₈	A ₉	A ₁₀	Thickness (nanometer)	400	330	300	250	210

Claims

1. one kind synthetic has a method of three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that the hydrolysis reaction in the alcohol/aqueous solution of long chain alkyl primary amine generates silicon oxide by methyl silicate or tetraethoxy, template is removed in high-temperature roasting then, and concrete grammar is:

(1) a certain amount of long chain alkyl primary amine is dissolved in alcohol, adds a certain amount of water and strong aqua then, stirring is dissolved the long chain alkyl primary amine of separating out again;

(2) take by weighing a certain amount of methyl silicate or tetraethoxy, add the alcohol/aqueous solution of the long chain alkyl primary amine of vigorous stirring, stop after continuing to be stirred to methyl silicate or tetraethoxy homodisperse, place certain hour at a certain temperature;

(3) will get product after product suction filtration, washing, drying and the high-temperature roasting;

Actual conditions is:

(1) consumption of long chain alkyl primary amine is every liter of solvent 1.5～5.5 grams, and the volume ratio of alcohol and water is 0.9～1.4, and the consumption of ammoniacal liquor is every liter of solvent 10～40 grams, and the consumption of methyl silicate or tetraethoxy is every liter of solvent 5～30 grams;

(2) the hydrolysis synthesis temperature is a normal temperature, and generated time is 4-24 hour;

(3) high-temperature roasting temperature is 500～650 ℃, and roasting time is 2～10 hours.

2. according to claim 1 synthesizing has the method for three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that long chain alkyl primary amine is the primary amine that cetylamine or stearylamine have the chain alkyl structure.

3. according to claim 1 synthetic have the method for three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that alcohol is any or their alcohol mixture in methyl alcohol, ethanol, n-propyl alcohol, the Virahol.

4. the synthetic method of three dimension continuous nano pore structure silicon oxide flakes that has according to claim 1, the consumption that it is characterized in that long chain alkyl primary amine is every liter of solvent 3.0～5.0 grams, the volume ratio of alcohol and water is 1.0～1.2, the consumption of ammoniacal liquor is every liter of solvent 20～30 grams, and the consumption of methyl silicate or tetraethoxy is every liter of solvent 15～25 grams.

5. according to claim 1 synthesizing has the method for three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that the hydrolysis synthesis temperature is 10～35 ℃, and generated time is 12～24 hours.

6. according to claim 1 synthesizing has the method for three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that maturing temperature is 550～600 ℃, and roasting time is 4～6 hours.

7. according to claim 1 synthetic have the method for three dimension continuous nano pore structure silicon oxide flakes, it is characterized in that the thickness of the silicon oxide flakes that obtains is 5-500nm.

8. have of the application of three dimension continuous nano pore structure silicon oxide flakes according to the described method synthetic of claim 1 in sorbent material or support of the catalyst field.