synthesis of carbon nano-materials by means of pulse

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IMR Symposium on Materials Sciences and Engineering 2007.7.11 Synthesis of carbon nano-materials by means of pulse modulated arc discharge in organic liquids Shin-ichi Kuroda and Katsuhiko Hosoi Graduate School of Gunma University E-mail [email protected]

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Page 1: Synthesis of carbon nano-materials by means of pulse

IMR Symposium on Materials Sciences and Engineering 2007.7.11

Synthesis of carbon nano-materialsby means of

pulse modulated arc dischargein organic liquids

Shin-ichi Kuroda and Katsuhiko Hosoi

Graduate School of Gunma University E-mail [email protected]

Page 2: Synthesis of carbon nano-materials by means of pulse

Energy

Medical treatment

Composite material

Nanotechnology

Electronic discharge

Electronics

【Carbon Nanotube(CNT)】

The carbon material of a nanometer order

Introduction

carbon nano structure

Page 3: Synthesis of carbon nano-materials by means of pulse
Page 4: Synthesis of carbon nano-materials by means of pulse
Page 5: Synthesis of carbon nano-materials by means of pulse

"arc in liquid" methodsThe technique of causing electric discharge between graphite electrodesin liquid

Introduction (2)

liquid nitrogen or deionized water

A carbon nanostructure can be preparedwith being highly dispersed in a liquid.

Arc dischargeLaser ablation

CVD

Synthesis of CNTs

•Large-size equipments •High running costs

disadvantage

M. Ishigami, Cumings J., Zettl A., Chen S. Chem. Phys. Lett. 2000, 319, 457.

N. Sano, Weng H., Chhowalla M., Alexandrou I., Amratunga G. A. J., Nature 2001, 414, 506.

Page 6: Synthesis of carbon nano-materials by means of pulse

・・ ・

・・

Fragments of liquid molecules

For the conventional technique,the graphite used for electrode is a source of carbon.

In this research, since metal electrode is used, an organic liquid becomes the source of carbon.

Needle-like electrode SUS plateThe enlargement of bubbles

Generating bubbles

Quenching with a surrounding liquid Synthesis of the carbon nano structure

Characteristics of this work

Breakdownelectric discharge

Page 7: Synthesis of carbon nano-materials by means of pulse

Effects of molecular structureof liquid carbon source

on the synthesisof carbon nanostructuresby arc in liquids method

Page 8: Synthesis of carbon nano-materials by means of pulse

Between electrodes:About 0.5 mm

Ground

Under nitrogen atmosphere

SUS plate

organic liquid : 500 ml

Needle-like iron electrodelength : 20 mmdiameter : 1.5 mm

micropositioner Impulse power supply

kV kWON

kHz

FeNi 0.1 wt%

30

Pulse width 30 μs

Experimental apparatus

Catalyst

Page 9: Synthesis of carbon nano-materials by means of pulse

dichloromethane carbon tetrachloride

hexaneCH3C(CH3)2CH2CH(CH3)CH3

2,2,4-trimethyl pentane

C

H

Cl Cl

Cl

C

Cl

Cl Cl

Cl

C

H

H Cl

Clchloroform

CH3(CH3)4CH3 CH3(CH3)6CH3octane

CH3OHmethanol

C2H5OC2H5diethyl ether

HCHOformaldehyde

(CH3)2COacetone

organic liquids

Page 10: Synthesis of carbon nano-materials by means of pulse

muddy black

C

H

H Cl

Cl

C

H

Cl Cl

Cl

C

Cl

Cl Cl

Cl11.0 11.5 12.5

CH3C(CH3)2CH2CH(CH3)CH3

11.5

Breakdown voltage 〔kV〕

・Electric discharge takes place with intense light and sound.⇒The soot-like products were formed in liquid.

・Electrode was consumed slightly.

・Temperature of liquid rose by 2 to 5 degrees.

・Chlorine-containing gas was generated.

Electric discharge /Change in the liquid

Page 11: Synthesis of carbon nano-materials by means of pulse

slightly black Breakdown voltage 〔kV〕

CH3(CH3)4CH37.5

CH3(CH3)6CH38.0

(CH3)2CO7.0

no change

CH3OH4.5

C2H5OC2H57.0

HCHO4.0

Change in the liquid

Page 12: Synthesis of carbon nano-materials by means of pulse

0

4

8

12

16

0 10 20 30

Carbon tetrachloride

chloroform 2,2,4-trimethyl pentane

+ octane

×dichloromethane hexane

×diethyl ether acetone

methanol formaldehydeMolecule volume  [10-23 cm3]

Bre

akdo

wn

volta

ge [k

V]

Relation between molecular volume and breakdown voltage

Page 13: Synthesis of carbon nano-materials by means of pulse

0

4

8

12

16

0 10 20 30

◆ Additive-free

Ni Add

Fe Add

Molecular volume [10-23 cm3]

Bre

akdo

wn

volta

ge [k

V]

Change of the breakdown voltage by catalyst addition

Page 14: Synthesis of carbon nano-materials by means of pulse

One drop of liquid after electric discharge on a micro grid.

After dried up, TEM observation was performed.

mesh

TEM observation

Page 15: Synthesis of carbon nano-materials by means of pulse

The products observed on a micro grid were classified into the following three types.

100 nm

①Amorphous particle ②Crystalline substance

200 nm

500 nm 100 nm

200 nm

③Unique structure

Those what with peculiarstructure different from ①or ②.

Classification of products

Page 16: Synthesis of carbon nano-materials by means of pulse

100 nm

200 nm

50 nm

100 nm

Graphite ball

Without catalyst, amorphous particles of diameter 5-100 nm were dominant and no unique structure was observed.

Scattered state

100 nm

100 nmtorn form

Catalyst-free system

Page 17: Synthesis of carbon nano-materials by means of pulse

200 nm

MeOH+Fe CHCl3+Ni

100 nm

500 nm

100 nm

CCl4+Ni

200 nm

200 nm

With addition of catalyst, unique carbon nanostructures wereobserved on some parts of micro grid.

Example of unique structure products①

Page 18: Synthesis of carbon nano-materials by means of pulse

CH2Cl2+Ni

200 nm

500 nm

CH3C(CH3)2CH2CH(CH)3CH3+Ni

500 nm

50 nm

100 nm

200 nm

Example of unique structure products②

Page 19: Synthesis of carbon nano-materials by means of pulse

octane+Fe 8.5 light 2,2,4-trimethyl pentane+Fe 11.5 Deep-black

C C C C CC

C

C

Unique structure

Amorphous particle

Crystalline substance

50% 65%

50% 30%

0% 5%

A classification of a products

100 nm

Influence of fragmentation on products

Page 20: Synthesis of carbon nano-materials by means of pulse

formaldehyde+Fe acetone+FeO

HC

H

O

CH3

CH3C

100 nm

100 nm

70 percent of a domain is the shape of amoeba.

500 nm

500 nm

500 nm

Influence of functional group on products

Page 21: Synthesis of carbon nano-materials by means of pulse

H3C

The fraction of a crystalline particle

CH3OH

C2H5OC2H5

OH

CH

OCH3C

CC C C C

C

C

C2-3%

0%

2-3%

5%

30%

CC

CC

CC

CC

CC

CC

CC

30%

50%

The fraction of crystalline particle increases with main chain length of source molecule.

Relationship between main chain structure and crystalline products

Page 22: Synthesis of carbon nano-materials by means of pulse

CCl Cl

H

H

CCl Cl

Cl

H

CCl Cl

Cl

Cl

Fraction of crystalline particle

20%

25%

40%

Fraction of unique structure

0%

500 nm 200 nm

500 nm

500 nm

10%

5%

Specificity of chlorine-containing compounds

Page 23: Synthesis of carbon nano-materials by means of pulse

・Without catalyst, only amorphous particles with diameter 5-100 nm were obtained. By addition of catalyst (Ferrocene, Nickelocene) carbon nanostructures were obtained.・The functional group and small fragmentation of each liquid had great effects on obtained structure.・The longer the main chain of liquid molecule is, the more the crystalline products were obtained.・The chlorine-containing compound exceptionally did give crystalline products despite the number of C is one.

conclusions

Page 24: Synthesis of carbon nano-materials by means of pulse

Synthesis of carbon nanostructures by pulsed electric discharge

between metal electrodes using fluorine-containing organic liquid

Page 25: Synthesis of carbon nano-materials by means of pulse

volt.(kV) power(kW)

14kHz-5s 5.0 0.2514kHz-10s 6.5 0.2514kHz-15s 8.0 0.4014kHz-20s 6.0 0.30

mol% C F O F/C O/C14kHz-5s 80.48 7.08 12.44 8.797 15.4614kHz-10s 78.81 8.85 12.34 11.23 15.6614kHz-15s 81.07 14.98 3.96 18.48 4.8914kHz-20s 80.4 12.23 7.37 15.21 9.17

HFE-7200 28.57 66.67 4.76 150 16.66

Electric discharge conditions

Experimental conditions (Time change)

Atomic concentrations

HFE-7200C4F9OC2H5

Soot-like products were formed: 12.5 mg / A・s ≒ 30 times of previously reported rate.

Page 26: Synthesis of carbon nano-materials by means of pulse

1) 14kHz-5s 4) 14kHz-20s3) 14kHz-15s2) 14kHz-10s

TEM observation (Time change)

100nm

Amorphous particle Carbon nanotube

The carbon particle of about 5 - 100nm was observed.Some CNTs appeared with prolonged discharge time.

Page 27: Synthesis of carbon nano-materials by means of pulse

mol% C F O F/C O/C5kHz-10s 80.82 13.92 5.25 17.22 6.5030kHz-10s 80.55 13.59 5.87 16.87 7.2945kHz-10s 80.44 12.69 6.86 15.78 8.5360kHz-10s 80.37 12.4 7.23 15.43 9.00

volt.(kv) power(kw)5kHz-10s 8.5 0.1514kHz-10s 6.5 0.2530kHz-10s 5.5 0.2045kHz-10s 7.5 0.2560kHz-10s 7.0 0.25

Electric discharge conditions

Experimental conditions (Frequency change)

Surface atomic concentrations

Page 28: Synthesis of carbon nano-materials by means of pulse

4) 60kHz-10s

2) 30kHz-10s

3) 45kHz-10s

1) 5kHz-10s

TEM observation (Frequency change)

2) 14kHz-10s

100nm

Carbon nanotubeAmorphous particle

About 10nm diameter carbon nanotube was observed except for 5kHz-10s.Most CNTs were observed in 30kHz-10s.

Page 29: Synthesis of carbon nano-materials by means of pulse

1100 1200 1300 1400 1500 1600 1700 1800

Raman spectrum

G-band(1590cm-1)Graphite

D-band(1350cm-1)Disorder

IGID

G/D ratio = IG / IDThe Raman measurement result was caliculatedfor the rate of a graphite and an amorphous.

Page 30: Synthesis of carbon nano-materials by means of pulse

0.0

0.5

1.0

1.5

2.0

2.5

14KHz 10s 30KHz 10s 45KHz 10s 14KHz 30s

G/D ratio (Frequency & time change)G

/D ra

tio

The G/D ratio decreased according to the increase in electric discharge frequency.When electric discharge time was extended, the G/D ratio increased.

Page 31: Synthesis of carbon nano-materials by means of pulse

Surface atomic concentrations (Change in catalyst concentration)

Time change 20s 79.53 15.46 3.33 1.67 19.44 4.1930s 78.57 15.03 4.80 1.60 19.13 6.11

Frequencychange

30kHz 75.79 14.79 7.59 1.83 19.51 10.0145kHz 77.68 15.68 5.16 1.48 20.19 6.64

The amount change of catalysts

atomic concentrations(mol%) Composition ratio(%)C F O Fe F/C O/C

0.01% 80.77 14.11 3.82 1.30 17.47 4.730.05% 76.24 14.12 7.69 1.95 18.52 10.090.10% 81.54 12.98 4.39 1.08 15.92 5.380.30% 78.71 15.49 4.18 1.63 19.68 5.310.50% 81.69 11.90 5.04 1.36 14.57 6.17

HFE-7200 37.50 56.25 6.25 0.00 150.00 16.67

Catalyst addition

C F O F/C O/C10s 78.81 8.85 12.34 11.23 15.6615s 81.07 14.98 3.96 18.48 4.8920s 80.40 12.23 7.37 15.21 9.17

30kHz 80.55 13.59 5.87 16.87 7.2945kHz 80.44 12.69 6.86 15.78 8.53

Addtion-free

Time change

Frequency change

atomic concentrations(mol%) Composition ratio(%)

Page 32: Synthesis of carbon nano-materials by means of pulse

TEM observation (Change in catalyst concentration) 1

50nm 20nm

Electric discharge conditions:14kHz,10s, a-1 a-2:Fe0.01%

a-1) a-2)A crystalline particleAmorphous particle

The carbon particle of about 5 - 100nm was observed for all products.Although CNT was hardly observable, particles of entangled CNT were observed.

Page 33: Synthesis of carbon nano-materials by means of pulse

TEM observation (Change in catalyst concentration) 2

50nm

Electric discharge conditions:14kHz,10s, b-1 b-2:Fe0.05%,c:Fe0.1% d:Fe0.3% e:Fe0.5%

b-1) b-2)

d)

c)

e)

50nm 20nm

20nm

20nm

20nm

Metal encapsulated particle A crystalline particle

Amorphous particle

Page 34: Synthesis of carbon nano-materials by means of pulse

TEM observation (Frequency change)

50nm 50nm

Electric discharge conditions:10s Fe0.1%,a:30kHz,b:45kHz

a) b)

20nm20nm

Amorphous particleCrystalline particle

Page 35: Synthesis of carbon nano-materials by means of pulse

TEM observation (Time change)

50nm 50nm

20nm20nm

Electric discharge conditions :14kHz,Fe0.1% ,a:20s,b:30s

a) b)Crystalline particleCNT

Page 36: Synthesis of carbon nano-materials by means of pulse

1100 1200 1300 1400 1500 1600 1700 1800

Raman spectrum

G-band(1590cm-1)GraphiteD-band(1350cm-1)

Disorder

IGID

G/D ratio = IG / ID

Page 37: Synthesis of carbon nano-materials by means of pulse

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

14kHz Fe0.1% 10s 30kHz Fe0.1% 10s 45kHz Fe0.1% 10s 14kHz Fe0.1% 30s

G/D ratio (Change in catalyst consentration)G

/D ra

tio

The G/D ratio decreased according to the decrease in electric discharge frequency.When electric discharge time was extended, the G/D ratio increased.

Page 38: Synthesis of carbon nano-materials by means of pulse

•Carbon nanostructures were prepared by pulse-modulated discharge in fluorine-containing organic liquid without using graphite electrodes. •The formation rate of product was found to be about 30 times faster than that by the “arc in liquid” method previously reported. •The product consists of nanoparticles andMWCNTs with fluorine on their surface.•Crystallinity increased according to frequency.

Conclusions