POSTGRADUATE MASTER PROGRAMMEMATERIALS SCIENCE CENTRE

The growth mechanism for the catalytic of carbon nanotubes

POSTGRADUATE MASTER PROGRAMMEMATERIALS SCIENCE CENTRE

The growth mechanism for the catalytic of carbon nanotubes

Sho-Yen Lin (PMSC)

Date: 25th/June/2007

2

OverviewOverview• IntroductionIntroduction

• Structure of carbon nanotubesStructure of carbon nanotubes

• Production of carbon nanotubesProduction of carbon nanotubes

• ExperimentExperiment• AimsAims• Catalytic chemical vapor deposition method (CVD)Catalytic chemical vapor deposition method (CVD)

• FEGSEMFEGSEM

• TGATGA

• Raman SpectroscopyRaman Spectroscopy

• SummarySummary

• ConclusionsConclusions

Introduction of carbon nanotubesIntroduction of carbon nanotubes

• Allotropes of carbon:

Graphite

Diamond

C60

SWNTs MWNTs

http://www.photon.t.u-tokyo.ac.jp/~maruyama/agallery/agallery.html

Structure of carbon nanotube Structure of carbon nanotube

Chiral

Conductivity depends on nanotubes chirality (symmetry)

Armchair – metallic Zigzag – 1/3 metallic 2/3 semiconducting Chiral – semiconducting

a1a2

x

y

(0,0) (1,0) (2,0) (3,0)

(1,1) (2,1)

Zigzag

Armchair

(2,2)

(4,0) (5,0) (6,0)

(3,1) (4,1) (5,1)

(3,2) (4,2) (5,2)

(7,0) (8,0) (9,0)

(6,1) (7,1) (8,1)

(6,2) (7,2) (8,2)

(10,0) (11,0)

(9,1) (10,1)

(9,2) (10,2)

(3,3) (4,3) (5,3) (6,3) (7,3) (8,3) (9,3)

(4,4) (5,4) (6,4) (7,4) (8,4) (9,4)

(5,5) (6,5) (7,5) (8,5)

(6,6) (7,6) (8,6)

(7,7)

http://www.photon.t.u-tokyo.ac.jp/~maruyama/agallery/agallery.html

Ni-nitrateC

C

CC

C

CVD growth model (Baker theory)CVD growth model (Baker theory)

Ni-nitrateC

C

CC

CNi-nitrate

CH4

CH4 CH4

CH4

CH4

Finalized CNT growth

CNT growth in process

ExperimentExperiment

Synthesis of catalyst1. Ingredient of catalyst: Solvent: Ethanol

Acetone (more even covering) Nickel nitrate

2. Silica substrate: Fumed silica

3. Dry while stirring4. Dry at 40 ℃ overnight

Aims :Understand CNT growth

(i)Measure mass during the growth

(ii)Changing factors:

(a)Temperature

(b)Heating rate

(c)Catalyst loading (wt%)

Ni-nitrate + SiO2

Catalytic chemical vapor deposition method (CVD)

Catalytic chemical vapor deposition method (CVD)

(1)Ramp 2 /min to 40℃ ℃(2)Isothermal for 10 min (to remove water)(3)Ramp at 5, 20 or 50 /min to 700 ℃ ℃(4)Catalyst loading 5, 10 or 20 wt% Ni

Ni-nitrate +fumed silica

10%Methane in Argon

Effect of Ni loading in TGAEffect of Ni loading in TGA

Ni nitrate + water

Ni nitrate NiWater lossStarting temp

CNT yield

CNT growth

Effect of heating rate for different Ni loadings in TGA

Effect of heating rate for different Ni loadings in TGA

Relationship between different Ni loading and heating rate in TGA

Relationship between different Ni loading and heating rate in TGA

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 5 10 15 20 25

Ni% on initial particle/%

C%of fi

nal p

articl

e/%

5℃/min

20℃/min

50℃/min

5℃/min

20℃/min

50℃/min

5℃/min

20℃/min

50℃/min

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 5 10 15 20 25 30 35 40 45 50 55

Heating rate/℃/min

C% of

fina

l

5%

10%

20%

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 5 10 15 20 25 30 35 40 45 50 55

Heating rate/℃/min

C% of fi

nal

5%

10%

20%

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

100.00

0 5 10 15 20 25

Ni% on initial particle/%

C%of fi

nal p

artic

le/%

5℃/min

20℃/min

50℃/min

5℃/min

20℃/min

50℃/min

5℃/min

20℃/min

50℃/min

FEGSEMFEGSEM

Raman SpectroscopyRaman Spectroscopy

Ni-nitrate 5%

0100002000030000400005000060000700008000090000

100.72

313.67

526.61

739.56

952.51

1165

.4

1378

.4

1591

.3

1804

.3

2017

.2

2230

.2

2443

.1

2656

.1

2869

3082

3294

.9

Raman shift

50℃/min

RBM

G-band

D-bandG’-band

226

266

1588

13702590

Raman Spectroscopy:different heating rate v.s different loading

Raman Spectroscopy:different heating rate v.s different loading

Ni-nitrate 5%

020000400006000080000

100000120000140000160000

100.72

347.96

595.21

842.45

1089

.6

1336

.9

1584

.1

1831

.4

2078

.6

2325

.9

2573

.1

2820

.4

3067

.6

3314

.8wave number

50℃/min

20℃/min

5℃/min

Ni-nitrate10%

0

50000

100000

150000

100.78 301

501.22

701.44

901.65

1101

.8

1302

1502

.3

1702

.5

1902

.7

2102

.9

2303

.1

2503

.4

2703

.6

2903

.8

wave number

5℃/min

20℃/min

50℃/min

Ni-nitrate 5%

020000400006000080000

100000120000140000160000

100.72

347.96

595.21

842.45

1089

.6

1336

.9

1584

.1

1831

.4

2078

.6

2325

.9

2573

.1

2820

.4

3067

.6

3314

.8

wave number

50℃/min

20℃/min

5℃/minNi-nitrate20%

0

20000

40000

60000

80000

100.68

294.11

487.55

680.98

874.42

1067

.8

1261

.2

1454

.7

1648

.1

1841

.5

2035

2228

.4

2421

.9

2615

.3

2808

.7

wave number

50℃/min

20℃/min

5℃/min

Ni-nitrate10%

0

50000

100000

150000

100.78 301

501.22

701.44

901.65

1101

.8

1302

1502

.3

1702

.5

1902

.7

2102

.9

2303

.1

2503

.4

2703

.6

2903

.8

wave number

5℃/min

20℃/min

50℃/min

Ni-nitrate20%

0

20000

40000

60000

80000

100.6

829

4.11

487.5

568

0.98

874.4

210

67.8

1261

.214

54.7

1648

.118

41.5

2035

2228

.424

21.9

2615

.328

08.7

wave number

50℃/min

20℃/min

5℃/min

Raman Spectroscopy (IG/ID v.s different heating rate and IG/ID v.s different loading)

Raman Spectroscopy (IG/ID v.s different heating rate and IG/ID v.s different loading)

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25

Ni-nitrate wt%

5℃/min

20℃/min

50℃/min

IG/ID

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35 40 45 50 55

Heating rate/℃/min

5%

10%

20%

IG/ID

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25 30 35 40 45 50 55

Heating rate/℃/min

5%

10%

20%

IG/ID

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25

Ni-nitrate wt%

5℃/min

20℃/min

50℃/min

IG/ID

Summary

• Synthesis of catalyst by using Ni-nitrate (fumed silica)

• Producing carbon nanotubes by CVD

• TGA: Effect of Ni loading

Effect of heating rate for different Ni loadings

•FEGSEM

•Raman Spectroscopy:different heating rate vs. different loading IG/ID v.s different heating rate and IG/ID v.s different loading

Conclusion

The effect factors of CNTs growth

•Time: heating rate

longer time larger particles

•Temp: higher temp larger particles

•Metal catalyst: concentration

•Surface: roughness

SWNT

SWNT

SWNT

SWNT