CN1424254A

CN1424254A - Preparation of boron nitride nano tube

Info

Publication number: CN1424254A
Application number: CN 03114737
Authority: CN
Inventors: 张弜; 李宗全; 徐进
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2003-01-03
Filing date: 2003-01-03
Publication date: 2003-06-18
Anticipated expiration: 2023-01-03
Also published as: CN1208245C

Abstract

A process for preparing nanotubes of boron nitride (BN-NTs) includes such steps as dissolving H3BO3, CO(NH2)2 and Fe(NO3)3.9H2O or Co(NO3)2.6H2O, or Ni(NO3)2.6H2O) in deionized water, vacuum drying to obtain mixture powder, loading in open quartz tube, heating to 1000-1300 deg.C, holding the temp for 60-90 min, cooling, and immersing the powder in diluted nitric acid for removing catalyst. Its advantages are simple process and low cost.

Description

The method for preparing boron nitride nano-tube

Technical field

The present invention relates to a kind of method for preparing boron nitride nano-tube (BN-NTs).

Background technology

Since having found carbon nanotube (C-NTs) afterwards, with the BN that has hexagonal structure equally, BC ₃And BC ₂The whole bag of tricks that N prepares nanotube also occurs successively.Theoretical Calculation shows that the number of plies of diameter, spirality and tube wall of the energy gap of BN-NTs and nanotube is irrelevant, this than electrical properties along with the C-NTs that the textural factors such as the number of plies of diameter, spirality and the tube wall of nanotube change has more advantage, and BN-NTs is a stable structure, thereby unique application prospect is arranged on nano-device.BN-NTs has better high-temperature oxidation resistance than C-NTs in addition, is good heat conductor and isolator.

The method of using plasma arc-over has been synthesized BN-NTs at first.Laser ablation method also success synthesized BN-NTs.But the output of these two kinds of methods, purity are not high, and cost height, and complex process are unfavorable for industrial production.Develop the synthetic method that the carbon nanotube substitution reaction recently again, wherein the carbon nanotube role provides the skeleton of BN-NTs growth, BN-NTs that obtains and the similar of C-NTs, but the BN-NTs of this method preparation inevitably is mixed with C-NTs, and this has influenced the popularization of this method.Use the chemical Vapor deposition process (CVD) of metal catalyst can synthesize BN-NTs, but former CVD method all will feed reactant gases in addition, and some the catalyzer price that adopts is very high, this has also limited its application to a certain extent.

Summary of the invention

The method that the purpose of this invention is to provide a kind of BN-NTs of preparation, its selects urea and boric acid respectively as N source and B source, introduces Fe, or Co, or Ni need not other reactant gases as catalyzer, can prepare a large amount of high-quality BN-NTs.

It comprises following step the technical solution used in the present invention: 1) with chemical pure H ₃BO ₃, CO (NH ₂) ₂And Fe (NO ₃) ₃9H ₂O or Co (NO ₃) ₂6H ₂O or Ni (NO ₃) ₂6H ₂O, its mol ratio 1: 2-5: 0.05-0.1 is dissolved in the deionized water together; 2) under 60-80 ℃ of constant temperature, in vacuum drying oven, evaporated 6-10 hour then, remove the water in the solution, obtain the blended powder; 3) mixed powder is put into quartz boat, place the silica tube central thermal zone that adopts the horizontal chamber oven heating then, the silica tube two ends communicate with atmosphere, when temperature rises to 1000-1300 ℃, and constant temperature 60-90 minute; 4) wait until that then temperature reduces to room temperature, take out quartz boat, obtain linen powder.5) again powder was soaked 8-12 hour with rare nitric acid (20-30wt%), remove catalyzer, obtain the pure BN-NTs of white.

Characteristics of the present invention: 1. by thorough mixing H in solution ₃BO ₃, CO (NH ₂) ₂And Fe (NO ₃) ₃9H ₂O or Co (NO ₃) ₂6H ₂O or Ni (NO ₃) ₂6H ₂O, remove the water in the solution after, can obtain at the mixed powder of molecular level.Contact well thus between catalyzer and the reactant, help the BN-NTs of growing high-quality.2. be reflected in the silica tube of opening and carry out, need not to feed in addition other reactant gasess.3. this method technology is simple, and cost of material is cheap, and cost is low, and reaction is easy to control.

Description of drawings

Fig. 1 is the transmission electron microscope photo (amplifying 40,000 times) of embodiment gained BN-NTs;

Fig. 2 is the high-resolution electron microscope photo (amplifying 410,000 times) of embodiment gained BN-NTs.

Embodiment

Embodiment:

Take by weighing 0.602gCO (NH respectively ₂) ₂, 0.618gH ₃BO ₃, 0.404gFe (NO ₃) ₃9H ₂O (mol ratio is 1: 3: 0.1) is dissolved in the 300ml deionized water together, and heating 6h obtains filemot mixed powder except that anhydrating in 60 ℃ of homothermic vacuum drying ovens then.Again this powder is put into quartz boat, place by horizontal chamber oven heating the silica tube central thermal zone.The silica tube both ends open communicates with atmosphere.Be warming up to 1000 ℃, be incubated 60 minutes.Concrete process is as follows: urea begins fusing and decomposites NH after temperature surpasses 133 ℃ ₃, at about NH more than 700 ℃ ₃Just can with H ₃BO ₃Reaction generates BN.While Fe (NO ₃) ₃At pyrolytic decomposition is Fe ₂O ₃And oxynitride.NH ₃Have reductibility, Fe can be restored.Under the katalysis of Fe nanoparticle, grow BN-NTs.

Product is a pale powder, measures with X-ray diffraction to show that wherein main component is hexagonal BN, and Fe ₂O ₃, Fe ₂O ₃Be catalyzer oxidized product in reaction, can remove with rare nitric acid (30%) very easily.Product disperses the back to observe under transmission electron microscope with dehydrated alcohol.Find a large amount of BN-NTs, the diameter range of nanotube is at 30-50nm, several microns long (seeing accompanying drawing 1).The BN-NTs structure of growing as can be seen by the observation of high-resolution electron microscope is very complete, and internal diameter and external diameter are respectively 15nm and 40nm (seeing accompanying drawing 2).

Claims

1. a method for preparing boron nitride nano-tube is characterized in that it comprises the steps:

1) chemical pure H ₃BO ₃, CO (NH ₂) ₂And Fe (NO ₃) ₃9H ₂O or Co (NO ₃) ₂6H ₂O, or Ni (NO ₃) ₂6H ₂O, its mol ratio 1: 2-5: 0.05-0.1 is dissolved in the deionized water together;

2) under 60-80 ℃ of constant temperature, in vacuum drying oven, evaporated 6-10 hour then, remove the water in the solution, obtain the blended powder;

3) mixed powder is put into quartz boat, place the silica tube central thermal zone that adopts the horizontal chamber oven heating then, the silica tube two ends communicate with atmosphere, when temperature rises to 1000-1300 ℃, and constant temperature 60-90 minute;

4) wait until that then temperature reduces to room temperature, take out quartz boat, obtain linen powder;

5) again with rare nitric acid dousing 8-12 hour of powder usefulness 20-30wt%, remove catalyzer, obtain the pure BN-NTs of white.