CN100567147C - A kind of synthetic method of organic-inorganic composite silicon oxide nanowire - Google Patents

Abstract

The invention belongs to the field of polymer materials, and mainly relates to a method for synthesizing organic-inorganic composite silicon oxide nanowires. In the method, amorphous silicon oxide is used as a silicon source, and an organic-inorganic composite silicon oxide nanowire is generated through a liquid-solid phase reaction of an organic amine aqueous solution in one step in the presence of iron. The synthesis method is simple and cheap. The obtained silicon oxide nanowires with organic-inorganic composite structure have good fluorescence activity, high specific surface area, high electrical insulation performance, rich surface silanol, etc., so they are widely used in micro-nano device assembly, nano-array research, nano- Optical transmission, nano-high insulation resistance and other fields have great application potential; at the same time, this organic-inorganic composite silicon oxide nanowire, as an emerging nanomaterial, is widely used in traditional industrial catalysis, polymer material reinforcement, and cosmetic enhancement. White anti-ultraviolet and other fields also have broad prospects.

Description

A kind of synthetic method of organic-inorganic composite silicon oxide nanowire

technical field

The present invention utilizes the condition of liquid-solid phase hydrothermal reaction to prepare amorphous silicon oxide into silicon oxide nanowires with organic-inorganic composite structure in aqueous solution of ethylenediamine; the silicon oxide with organic-inorganic composite structure The nanowires will be transformed into pure inorganic silicon oxide nanoparticles after pickling or firing.

Background technique

Nanoscience has advanced rapidly since the first discovery of carbon nanotubes in the 1990s. In the preparation of nanomaterials, according to the morphology of nanomaterials, they can be divided into: zero-dimensional nanomaterials such as nanoparticles, one-dimensional nanomaterials such as nanowires, nanotubes, nanorods, and nanohelices, and two-dimensional nanomaterials such as nanosheets and nanomaterials. tapes, three-dimensional nanoarrays, and more. Due to the microscopic quantum effects, various nanomaterials with different shapes show different characteristics from traditional materials in terms of light, electricity, and magnetism. The nanomaterials themselves also have different characteristics due to their different shapes.

Due to the characteristics of high insulation, good fluorescence effect, high surface area, and abundant silanol on the surface, one-dimensional silicon oxide nanowires are widely used in the fields of micro-nano device assembly, nano-array research, nano-optical transmission, and nano-high insulation resistance. It has great application potential, and as an emerging nanomaterial, one-dimensional silicon oxide nanowires also have broad prospects in the fields of traditional industrial catalysis, polymer material reinforcement, cosmetic whitening and UV protection. Therefore, the research on the synthesis method of one-dimensional silicon oxide nanowires is a research hotspot in the field of materials in recent years.

In the study of microstructure and synthesis mechanism, materials with organic-inorganic structure have become the focus and focus of recent attention (Th.Mayera, U.Weiler.Renewable Energy 2008, 33, 262; Xingwen Zhang, Lijiang Hu.Journal of Molecular Structure 2008, 872, 197; Jun-Wei Zhao, Shou-Tian Zheng. Journal of Solid State Chemistry 2007, 180, 3317; Cle′ment Roux, Feng Chai. Biomolecular Engineering 2007, 24, 549; Yinzhuang Zhou, Haiping Qiao. Inorganic Chemistry Communications 2007, 10, 1318; Je-Deok Kima, Toshiyuki Mori. Journal of Power Sources 2007, 172, 694). Due to the organic-inorganic doping in the structure, this kind of material with organic-inorganic composite nanostructure has different properties from pure inorganic materials in terms of optical, electrical, magnetic and other physical properties. More importantly, such materials It can not only have the characteristics of inorganic materials, but also have some properties of organic materials, which plays an important role in scientific research and production practice.

At present, the synthesis methods of silicon oxide nanowires mainly include physical and chemical methods. The physical method is mainly Laser Ablation Method (D.P.Yu, Q.L.Hang, Y.Ding Appl.Phys.Lett 1998, 73, 3076). The laser ablation method is to mix silicon, silicon oxide and iron catalysts in a certain proportion to make a target, and then use laser etching to grow silicon oxide nanowires at high temperature. This method requires high temperature and laser etching, which brings great difficulties to large-scale industrial production. Chemical laws mainly include: high temperature chemical vapor deposition (chemistry vapor deposition) (Y.J.Chen, J.B.Li.Appl.Phys.A 2002, 74, 433; Y.Q.Zhu, W.K.Hsu, David R.M.Walton.J.Mater.Chem 1998, 8 , 1859; H.F.Zhang, C.M.Wang, L.S.Wang Nano.Lett2003, 3, 577; B.Zheng, Y.Y.Wu, P.D.Yang, J.Liu.dver.Mater 2002, 14, 122; Z.L.Wang, Ruiping P.Gao. Adver.Mater 2000,12,1938; C.H.Liang, L.D.Zhang.J.Non-Cryst.Solids 2000,277,63), sol-gel (Sol-Gel) (M.Zhang, Y.Bando.J.Mater .Sci.Lett 1999, 18, 1911), Carbon-Assited Growth (B.L.V.Prasad.J.A.C.S 2003, 125, 10488), gas-solid phase hydrothermal synthesis (Ping Chen, Songhai Xie.J.A.C.S 2006, 128, 1470) and other methods. Among these methods, high-temperature chemical vapor deposition mixes silicon with metal catalysts (iron, cobalt, gold, nickel, gallium, etc.) by blowing gas at high temperatures, and grows silicon oxide nanowires under the action of metal catalysts. . This method can conveniently obtain silicon oxide nanowires, but the required reaction conditions are very harsh, and cannot meet the requirements of large-scale production of silicon oxide nanowires. The sol-gel method is to grow silicon oxide nanowires through the action of silicon source and template agent, and then remove the template agent by roasting or chemical etching, and finally obtain silicon oxide nanowires. This method does not require a high temperature and can grow nanowires under relatively mild conditions, but it needs to consume templates, the synthesis cost is high, and the roasting of templates will pollute the environment and is not suitable for large-scale production. Carbon-assisted growth is the growth of silicon oxide nanowires using carbon as a catalyst at high temperature. This method, like the high-temperature chemical vapor deposition method, requires very high temperatures, and it is also difficult to achieve large-scale production. The reaction conditions of hydrothermal synthesis are relatively mild, so it is more suitable for large-scale preparation. However, in the previous hydrothermal synthesis method, the catalytic metal needs to be loaded by roasting, which not only leads to cumbersome reaction steps and increased energy consumption, but also causes sintering and agglomeration of nano-scale silicon sources due to roasting. The reaction is not complete during the mass preparation process, resulting in a decrease in product purity and a low yield. In this patent we improved the hydrothermal synthesis process. A method different from the previous hydrothermal synthesis was found. This method not only has the advantages of hydrothermal synthesis, but more importantly, it further improves the yield and increases the output, which is completely suitable for the needs of large-scale industrial production.

Contents of the invention

The purpose of the present invention is to propose a liquid-solid phase hydrothermal synthesis method of organic-inorganic composite silicon oxide nanowires suitable for industrial production with simple process, low cost, high yield and high yield; the obtained organic-inorganic composite structure Pure inorganic silicon oxide nanowires can be obtained after the silicon oxide nanowires are pickled or roasted; this method can prepare silicon oxide nanowires in large quantities, conveniently and cheaply, and can be conveniently applied to industrial production processes.

The invention provides a method for synthesizing organic-inorganic composite silicon oxide nanowires, the method comprising the following steps:

(1) Using amorphous silicon oxide as raw material, add an iron salt solution with an iron element concentration of 0.1 to 2 mol/l or an iron hydroxide glue solution with an iron content of 0.1 to 2 mol/l and mix evenly. The molar ratio of silicon: iron is 1:0.1～2.5;

(2) Add ethylenediamine to the mixed solution in (1), mix the whole system evenly, the volume ratio of ethylenediamine to water in the reaction solution is 1:0.2~10; the mass ratio of amorphous silicon oxide to ethylenediamine It is 1:0.02 to 0.2.

(3) Transfer the mixed solution in (2) into a sealed reaction kettle for reaction, the reaction time is 0.5-30 days, and the reaction temperature is 160-250°C;

(4) Washing the product in (3) with water and organic solvents or one of them to obtain organic-inorganic composite silicon oxide nanowires; or pickling the product in (3) to obtain pure organic-inorganic silicon oxide Nanowires.

In the present invention, amorphous silica is any one of the following: mesoporous silica, white carbon black, or silica sol.

In the present invention, amorphous silica is silica sol.

In the present invention, the iron salt used is ferric chloride, ferric nitrate, ferric sulfate or ferric acetate.

In the present invention, the iron salt is ferric chloride.

In the present invention, the product in (3) is washed with water and anhydrous acetic acid in turn.

In the present invention, the volume ratio of ethylenediamine to water is 1:0.5-5.

In the present invention, the reaction temperature in (3) is 180-220° C., and the time is 3-8 days.

In the present invention, the organic solvent used for cleaning is ethanol, acetone, ether, methanol, benzene or toluene.

In the present invention, after the product in (3) is washed with 0.1～5mol/l acid solution to remove the loaded iron, the product is a white powdery solid, and the pickling treatment temperature is 30～100° C., and the time is 0.2～10 hours. The solid powder is washed with water to obtain pure inorganic silicon oxide nanowires.

In the present invention, the acid solution is hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid or acetic acid solution.

In the present invention, the acid concentration is 0.5-5 mol/l.

In the present invention, the acid treatment temperature is 40-90° C., and the time is 0.5-3 hours.

The silicon oxide nanowire prepared by the method of the invention has an organic-inorganic compound structure, which not only helps to study the formation mechanism of the nanowire, but also makes the surface of the nanowire have properties different from those of general silicon oxide materials. The silicon oxide nanowire prepared by the method of the present invention has a unique organic-inorganic composite structure, which leads to its unique properties such as high insulation, good fluorescence effect, high surface area, and abundant silicon hydroxyl groups on the surface. Therefore, this silicon oxide Nanowires are expected to have potential applications in many fields such as bioluminescent labeling, nano-device assembly, microscopic conduction, and synthesis of optical, electrical, and magnetic materials. The method of using liquid-solid phase hydrothermal synthesis of organic-inorganic composite silicon oxide nanowires has simple steps, low cost of process conditions, high product purity, large output, simple preparation process, reaction equipment, and low preparation cost, so it is very suitable for large-scale synthesis.

Description of drawings

Figure 1 is a SEM image of silica sol _A1 .

Fig. 2 is an SEM image of the organic-inorganic composite silicon oxide nanowire _A2 .

Fig. 3 is a SEM image of pure inorganic silicon oxide nanowire _A3 .

Fig. 4 is an SEM image of white carbon black B1.

Figure 5 is a SEM image of product _B2 .

Fig. 6 is a TEM image of product _B3 .

Fig. 7 is an SEM image of HMS silica pellet _C1 .

Figure 8 is a SEM image of product _C2 .

Figure 9 is a SEM image of product _C3 .

FIG. 10 is a SEM image of product _D1 .

Figure 11 is a TEM image of product _A2 .

Figure 12 is a high magnification TEM image of product A2.

Figure 13 is the XRD pattern of product _A2 .

Figure 14 is the XRD pattern of product _A3 .

Figure 15 is the infrared spectrum of product _A2 .

Figure 16 is the infrared spectrum of product _A3 .

Detailed ways

Example 1

Disperse 3.75g of silica sol (with a silicon oxide content of 40%) _A1 in 25ml of 0.5mol/l ferric chloride solution and oscillate. After the system is uniformly mixed, add 40ml of ethylenediamine solution, oscillate, and sonicate for 15 minutes. Transfer the well-mixed mixture into a reaction kettle with a polytetrafluoroethylene liner, tighten the reaction kettle and place it in an oven at 200°C for 5 days of reaction; take out the reacted green solid with water and ethanol respectively After washing 5 times, a silicon oxide nanowire A ₂ with an organic-inorganic composite structure will be obtained. The silicon oxide nanowires with an organic-inorganic composite structure were stirred with 1 mol/l hydrochloric acid solution for 1 hour at a temperature of 80°C; finally, the solids treated with hydrochloric acid were washed with water three times, and dried at room temperature to obtain a white powder Solid pure inorganic silica nanowires A ₃ .

Example 2

The experiment was carried out in the same manner as Example 1, but 3.75g of silica sol A ₁ was replaced by 1.50g of white carbon black B ₁ to obtain product B ₂ (before pickling) and B ₃ (after pickling).

Example 3

Experiment with the same method as Example 1, but replace 3.75g of silica sol _A1 with 1.50g of HMS silica pellets _C1 to obtain product _C2 (before pickling) and _C3 (after pickling).

Example 4

Carrying out the same experiment as Example 1, but substituting ethylenediamine for 1,6-hexamethylenediamine, will give partially reacted product _D1 .

Example 5

Experiment with the same method as Example 1, but replace ferric chloride with ferric hydroxide, ferric nitrate, and ferric sulfate. After the reaction, silicon oxide nanowires E ₁ , E ₂ , and _E3 .

Example 6

The experiment was carried out with the same method as Example 1, but when the volume ratio of ethylenediamine and water in the system was changed from 1:0.625 to 1:5, silicon oxide nanowires F ₁ with an organic-inorganic composite structure were obtained after the reaction.

Example 7

The same method as Example 1 was used for the experiment, but when the reaction temperature was changed from 200°C to 170°C and 22°C during the reaction, organic-inorganic composite silicon oxide nanowires G ₁ and G ₂ could be obtained after the reaction.

Example 8

The experiment was carried out with the same method as Example 1, but the reaction time was changed from 5 days to 3 days and 15 days during the reaction, and organic-inorganic composite silicon oxide nanowires H ₁ and H ₂ could be obtained respectively after the reaction.

Example 9

The same method as in Example 1 was used for the experiment, but the ethanol was replaced with toluene, diethyl ether, and acetone when cleaning the product, and the organic-inorganic composite silicon oxide nanowires I ₁ , I ₂ , and I ₃ could also be obtained.

Example 10

The experiment was carried out with the same method as Example 1, but the hydrochloric acid solution was replaced by nitric acid solution and sulfuric acid solution during pickling, and pure inorganic silicon oxide nanowires J ₁ and J ₂ could be obtained respectively after pickling.

Example 11

Carry out the experiment with the same method as example 1, but change the hydrochloric acid solution concentration from 1mol/l to 0.5mol/l, 4mol/l during pickling, and also can obtain pure inorganic silicon oxide nanowires _K1 respectively after pickling , K ₂ .

Example 12

The experiment was carried out with the same method as Example 1, but the pickling temperature was changed from 80°C to 50°C during pickling, and pure inorganic silicon oxide nanowires L ₁ could also be obtained after pickling.

Example 13

The experiment was carried out with the same method as in Example 1, but no ethylenediamine was added to the reaction system, and the product nanowires could not be obtained after the reaction.

Example 14

Experiment with the same method as Example 1, but do not add iron trichloride to the reaction system, then the product nanowires cannot be obtained after the reaction.

The scanning electron micrographs (SEM) of the above products were all taken on the Philips XL30 D6716 instrument, and the lens pictures (TEM) were taken on the JEOL JEM-2010 instrument. It can be seen from Figures 2, 3, 5, 6 and 8, 9 that the products A ₂ , A ₃ , B ₂ , B ₃ , C ₂ , and C ₃ have a one-dimensional wire-bound structure. The obtained products A ₂ and A ₃ were characterized by XRD (conducted on a Rigaku D/Max-IIA X-ray diffractometer, see Figs. 13 and 14 ). At the same time, the obtained products A ₂ and A ₃ were characterized by infrared absorption spectroscopy (conducted on a Nicolet Nexus 470 infrared spectrometer). It can be seen from Figure 15 that product A ₂ has an organic-inorganic composite structure, and Figure 16 shows that product A ₃ after acid washing has become a purely inorganic nanowire structure; the products B ₃ and C 3 obtained in examples 2 and ₃ are the same as A ₃ is also the same and belongs to the same substance.

Claims (8)

1. the synthetic method of an organic-inorganic composite silicon oxide nano-line is characterized in that, this method may further comprise the steps:

(1) be raw material with unformed silicon oxide, add ferro element concentration and be the molysite aqueous solution of 0.1～2mol/l or ironic hydroxide glue that iron level is 0.1～2mol/l and mix silicon: the molar ratio of iron is 1: 0.1～2.5;

(2) add quadrol in the mixed solution in (1), whole system mixes, and the volume ratio of quadrol and water is 1: 0.2 ~ 10 in the reaction soln; Unformed silicon oxide and quadrol mass ratio are 1: 0.02～0.2;

(3) react 0.5～30 day reaction times, temperature of reaction 160-250 ℃ among the mixed solution in (2) being changed over to the reactor of sealing;

(4) product in (3) is obtained organic-inorganic composite silicon oxide nano-line after water and organic solvent or wherein a kind of cleaning.

2. synthetic method according to claim 1 is characterized in that unformed silicon oxide is any in following: mesopore silicon oxide, white carbon black or silicon sol.

3. synthetic method according to claim 2 is characterized in that amorphous silicon oxide is a silicon sol.

4. synthetic method according to claim 1 is characterized in that used molysite is iron(ic) chloride, iron nitrate, ferric sulfate or iron acetate.

5. synthetic method according to claim 4 is characterized in that molysite is an iron trichloride.

6. synthetic method according to claim 1, the volume ratio that it is characterized in that quadrol and water are 1: 0.5～5.

7. synthetic method according to claim 1 is characterized in that the temperature of reaction in (3) is 180～220 ℃, 3～8 days time.

8. synthetic method according to claim 1 is characterized in that the organic solvent that is used to clean is ethanol, acetone, ether, methyl alcohol, benzene or toluene.

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