CN101698234B

CN101698234B - Chemical preparation method of metal cobalt nanowire

Info

Publication number: CN101698234B
Application number: CN2009102356895A
Authority: CN
Inventors: 孙冬柏; 俞宏英; 张冰聪; 孟惠民
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2009-10-21
Filing date: 2009-10-21
Publication date: 2011-02-16
Anticipated expiration: 2029-10-21
Also published as: CN101698234A

Abstract

A chemical preparation method for metal cobalt nanowires relates to the preparation of metal cobalt powder. The present invention adopts soft template method self-assembly method for preparing cobalt metal nanowires, which is characterized in that ethylene glycol and surfactant are used together to form a soft template, and hydrazine hydrate is used as a reducing agent to reduce cobalt ions in cobalt salts to cobalt atoms. And through the action of the soft template, the cobalt crystal nucleus grows directionally, and finally forms a linear shape. The diameter of the prepared nano cobalt wire is 100-800nm, the length can reach 2.0-10.0 μm, the aspect ratio is 12-25, and the powder composition is pure cobalt. The invention not only has simple process and low raw material cost, but also can realize economical macro-production, and provides conditions for the practical application of nano cobalt wires.

Description

A kind of chemical preparation process of metal cobalt nanowire

Technical field

The present invention relates to prepare the 1-dimention nano powder body material, particularly relate to the preparation of metal cobalt powder with chemical method.

Background technology

The nano-cobalt powder body is a kind of purposes powder body material very widely.Since its surface-active height, surperficial purity height, the pore-free seepage, specific area is big, has great skin effect and bulk effect, and in aspect application prospects such as catalysis material, electronic material, magnetic materials, makes it be subjected to people's attention day by day.Monodimension nanometer material shows many excellences and unique character, such as superpower mechanical strength, higher luminous efficiency, the thermoelectricity capability of enhancing etc., is very active field in the nanosecond science and technology field to its research.Monodimension nanometer material is assembled into the aggregation with particular geometric pattern, or it is carried out confinement growth and realize that its specific orientation can bring some brand-new overall coordination effects to monodimension nanometer material.This is for based on the nanoelectronic of monodimension nanometer material, the development of optics very important meaning being arranged.

Soft template method is the hole phase that adopts in the surfactant, be template promptly with rod-shaped micelle, microemulsion, in its duct, can the lead growth of nano material of surfactant, the wire micella makes that also the metal nucleus further growth of original production becomes the wire nano material.

According to " Science " 2001,291:2115～2117 reports, adopting TOPO and oleic acid intermixture is surfactant, o-dichlorohenzene is a solvent, thermal decomposition Co ₂(CO) ₈182 ℃ of preparation cobalt nanometer rods, its diameter is 4～25nm.Advantages such as this preparation method's nanometer rods is comparatively even, and dimensional controllability is strong, but TOPO and Co ₂(CO) ₈Comparatively expensive, limited its suitability for industrialized production.

According to " chemical journal " 2006,64 (4): 295～300 reports, by adding NaBH ₄As derivant, can at room temperature cause hydrazine and Co ²⁺Reduction reaction in water-ethanol system makes the high-purity nano metal cobalt powder.But the NaBH that uses in this method preparation process ₄Cost an arm and a leg and be difficult to obtain.

According to " Rare Metals Materials and engineering " 2007,36 (S2): 760～762 reports, adopt the solution reduction method, with polyvinylpyrrolidone PVP as surfactant, as reducing agent, through reflow treatment, the preparation dispersive property is cobalt nano-particle preferably with hydrazine hydrate.The advantage of this method is the reaction condition gentleness, and cost is lower, and repeatability is strong, and productive rate is high and easy to control.But particle size is bigger, skewness, and only prepared spheric granules.

According to " Crystal Growth﹠amp; Design " 2008,8 (9): 3206～3212 reports, adopting PVP k30 is soft template, under 200 ℃ of conditions, hydrazine hydrate reduction CoCl ₂Preparation cobalt submicron powder.Though the cobalt powder body of this method preparation is more even, the cobalt powder body is obviously spherical in shape, and exists the reaction time long, shape poor controllability, shortcoming such as the powder granule of preparation is bigger.

Summary of the invention

The object of the present invention is to provide a kind of method that adopts the soft template method self assembly to prepare metal cobalt nanowire, be characterized in utilizing ethylene glycol and surfactant to form soft template jointly, with the hydrazine hydrate is reducing agent, cobalt ions in the cobalt salt is reduced to cobalt atom, and makes cobalt nucleus oriented growth, finally form the pattern of wire by the effect of soft mode version, not only technology is easy, cost of material is cheap, and can realize economic magnanimity preparation, for the practical application of nanometer cobalt line provides condition.

Implementation process of the present invention is as follows:

1, the preparation of reaction solution:

With ethylene glycol is solvent, in solution cobalt salt 0.01～0.2mol/L, NaOH 0.04～0.4mol/L, the preparation of surfactant 1.0～10.0g/L ratio; Between 50～80 ℃ of reaction temperatures, magnetic agitation 20～30 minutes.

Wherein cobalt salt can be CoCl ₂, CoSO ₄And Co (NO ₃) ₂Among any;

Surfactant can be any among (polyvinylpyrrolidone) PVP k30, PVP k90, the PVP k360.

2, cobalt nanowire preparation:

The solution for preparing as stated above is heated to 90～150 ℃, adds hydrazine hydrate 10～50ml/L, reacted 20～30 minutes, finish until reaction, then centrifugation solution and cobalt nanowire are used the absolute ethanol washing cobalt nanowire 2～3 times again, the dry collection.

Compared with prior art, technical process of the present invention is simple, and reaction condition gentleness, preparation cost are cheap, therefore can realize the magnanimity preparation.Particularly adopting surfactant PVP is soft template, makes metallic cobalt can form the pattern of wire.Adopting the nanometer cobalt linear diameter of the present invention's preparation is 100～800nm, and length can reach 2.0～10.0 μ m, and draw ratio is 12～25, and its pattern is seen Fig. 1-Fig. 4.The powder composition for preparing is pure cobalt, and its constituent analysis the results are shown in Figure 5.

Description of drawings

Fig. 1 is the cobalt nanowire SEM photo of embodiment 1 preparation

Fig. 2 is the cobalt nanowire SEM photo of embodiment 2 preparations

Fig. 3 is the cobalt nanowire SEM photo of embodiment 3 preparations

Fig. 4 is the cobalt nanowire SEM photo of embodiment 4 preparations

Fig. 5 is the XRD figure spectrum of the powder of preparation

The specific embodiment

Embodiment 1:

1, the preparation of reaction solution:

With ethylene glycol is that solvent is in following ratio obtain solution.

CoCl ₂ 0.013mol/L

NaOH 0.05mol/L

PVP?k30 10.0g/L

50 ℃ of reaction temperatures

20 minutes magnetic agitation time

2, cobalt nanowire preparation:

1. the solution that will prepare as stated above is heated to 140 ℃;

2. drip hydrazine hydrate 50ml/L;

3. reacted 20 minutes, and finished until reaction;

4. centrifugation solution and cobalt nanowire;

5. use the absolute ethanol washing cobalt nanowire 3 times;

6. dry the collection.

Obtaining average length is 5.0 μ m, and average diameter is 200nm, and draw ratio is 25 nano-cobalt powder.Its pattern as shown in Figure 1.

Embodiment 2:

1, the preparation of reaction solution:

With ethylene glycol is that solvent is in following ratio obtain solution.

CoCl ₂ 0.05mol/L

NaOH 0.05mol/L

PVP?k30 10.0g/L

50 ℃ of reaction temperatures

Magnetic agitation 20 minutes

2, cobalt nano powder preparation:

1. the solution that will prepare as stated above places 95 ℃ of water-baths;

2. drip hydrazine hydrate 20ml/L

3. react and finished until reaction in 30 minutes;

4. centrifugation solution and cobalt nanowire;

5. use the absolute ethanol washing cobalt nanowire 3 times;

6. dry the collection.

Obtaining average length is 6 μ m, and average diameter is 250nm, and draw ratio is 24 nano-cobalt powder.Its pattern as shown in Figure 2.

Embodiment 3:

1, the preparation of reaction solution:

With ethylene glycol is that solvent is in following ratio obtain solution.

CoSO ₄ 0.02mol/L

NaOH 0.04mol/L

PVP?k90 10.0g/L

60 ℃ of reaction temperatures

Magnetic agitation 30 minutes

2, cobalt nano powder preparation:

1. the solution that will prepare as stated above is heated to 120 ℃;

2. drip hydrazine hydrate 30ml/L;

3. reacted 20 minutes;

4. centrifugation solution and cobalt nanowire;

5. use the absolute ethanol washing cobalt nanowire 3 times;

6. dry the collection.

Obtaining average length is 2.0 μ m, and average diameter is 163nm, and draw ratio is 13.4 nano-cobalt powder.Its pattern as shown in Figure 3.

Embodiment 4:

1, the preparation of solution:

With ethylene glycol is that solvent is in following ratio obtain solution.

Co(NO ₃) ₂ 0.02mol/L

NaOH 0.2mol/L

PVP?k360 10.0g/L

75 ℃ of reaction temperatures

Magnetic agitation 20 minutes

2, reaction cobalt nanowire preparation:

1. the solution that will prepare as stated above is heated to 120 ℃;

2. hydrazine hydrate 50ml/L;

3. reacted 30 minutes;

4. centrifugation solution and cobalt nanowire;

5. use deionized water, absolute ethanol washing cobalt nanowire 3 times respectively;

6. dry the collection.

Obtaining average length is 10 μ m, and average diameter is 800nm, and draw ratio is 12.5 nano-cobalt powder.Its pattern as shown in Figure 4.

Claims

1. a chemical preparation method of metallic cobalt nanowires, characterized in that the specific steps are:

1) Preparation of reaction solution

Use ethylene glycol as the solvent, and prepare according to the ratio of 0.01～0.2mol/L of cobalt salt, 0.04～0.4mol/L of NaOH, and 1.0～10.0g/L of surfactant in the solution; at the reaction temperature of 50～80℃, magnetic stirring 20-30 minutes;

2) Cobalt nanowire preparation

Heat the solution prepared by the above method to 90-150°C, add hydrazine hydrate 10-50ml/L, react for 20-30 minutes until the reaction is complete, then centrifuge the solution and cobalt nanowires, and then wash the cobalt with absolute ethanol Nanowire 2-3 times, dry collection;

Described tensio-active agent is any one in polyvinylpyrrolidone PVP k30, PVP k90, PVP k360.

2. The preparation method according to claim 1, wherein the cobalt salt is any one of CoCl ₂ , CoSO ₄ and Co(NO ₃ ) ₂ .