1. PREPARATION AND CHARACTERIZATION
OF CNTs ON Co-Mo SUBSTRATE USING
CVD METHOD
NAME: SITI ROHAYU BINTI RUBAIDI
MATRIC. NO: 1117322
SUPERVISOR: DR. MA’AN FAHMI AL-KHATIB
CO.SUPERVISOR: DR. SOUAD A.M. ALBAT’HI

2.  Discovered : S. Iijima - MWNT (1991), SWNT (1993).
 A tube-shaped material, made of carbon, having a diameter
measuring on the nanometer scale 1-100nm.
 Perfection!!
 Strongest and toughest
 Stiffest
 The best conductor
INTRODUCTION

3. PROBLEM STATEMENT
 Synthesis of CNTs have many methods and parameters such as the preparation of catalyst, selecting the
substrate and manipulating the process conditions of CNTs growth.
 Despite there are many number of studies on CNTs, there are still unsolved issues regarding the control of
process for production of SWCNT.
 In preparing CNTs, CVD equipment was used to obtain high yield and high purity of nanotubes.
 Certain parameter such as concentration ratio of catalysts and reaction temperature during CNTs growth
were varied in order to get optimum growth of CNTs.

4. OBJECTIVES
The objectives of this research are:
To prepare bimetallic catalyst on silica substrate.
To optimize the growth of CNTs on indium tin oxide (ITO) by
varying process parameters such as concentration ratio of
bimetallic catalyst, reaction temperature and gas flow rate.

5. METHODOLOGY
General flow of the project
Preparation of bimetallic catalyst with substrate by dip coated method. The
precursors of catalyst was mixed with ethanol solution
The CVD was set up and calcined catalyst was introduced in the middle of
quartz tubular reactor.
Reduction step:
Hydrogen was heated up to desired temperature (400◦C, 500◦C and 600◦C).
The process took almost 20 to 35 minutes. For CNTs Growth, Argon was
introduced up to 800◦C. At 800◦C, Carbon dioxide was introduced
subsequently for 1 hour.
The process was cooled in Argon flow up to room temperature.
The CNTs were collected and characterized by SEM
The substrate was dried in drying oven or flowing air and calcined
Modification of CVD reactor.
The process
was repeated
until desired
temperature
was obtained

6. The project was divided into two parts:
Preparation of catalyst on substrate
• Process of cleaning substrate
• Preparation of catalyst solutions on substrate
CNTs growth

7. Preparation of catalyst
A) Process of cleaning substrate
The glass of ITO was
cleaned by using
detergents, ethanol,
acetone and distilled
water.
The glass was dried in
drying oven before
proceeding to next
step.
The glass was tested
with multi meter to
identify the surface
that covered with ITO
The ITO glass was
baked at 500◦C for 5
minutes

8. B) Preparation of catalyst solutions on substrate
Catalyst powder of Cobalt II Nitrate and
Ammonium Heptamolybdate were weight based
on desired ratio of catalyst concentration.
The catalyst solution
dissolved in ethanol
solution were mixed
homogenously using
magnetic stirrer
Different solution
concentrations were
tested and evaluated in
the dip-coating process.
Coated catalyst of ITO
glass substrate were
placed in the crucible and
dried in room
temperature.
The glass substrates
were baked in
electrical furnace at
400◦C in 5 minutes.

9. CNTs growth
The tube was purged with Argon gas in 5 minutes.
Argon gas was switched off and hydrogen gas was introduced at flow rate 0.3 L/min. At the same time
the reactor was heated from room temperature up to 400◦C/ 500◦C /600◦C .
Hydrogen gas was switched off and argon gas was again introduced at flow rate of 0.7 L/min and the
reactor temperature was raised until 800◦C.
Consequently, carbon source which is carbon dioxide was introduced with flow rate 0.75 L/min n 1
hour.
Carbon dioxide flow was stopped and argon was introduced to cool down the sample until room
temperature.
The sample was collected and kept in the desiccator.

10. RESULTS
Sample after calcination
and reduction process
using CVD machine
Weighed the sample Stored the sample in
crucible and kept in the
desiccator

11. Catalyst and substrates after calcination and reduction

12. 0
0.2
0.4
0.6
0.8
1
1.2
400C 500C 600C
Yield(mg/mg)
Concentration ratio of catalyst
2:01 3:04 1:03 3:02
Yield = ( Weight of sample collected from CVD – Weight of calcined catalyst )
A) Carbon deposited in terms of increase of yield versus the concentration ratio of
bimetallic catalyst
Weight of calcined catalyst

13. B) Decreasing weight of samples after collected from CVD reactor according to
their respective temperature
0
50
100
150
200
250
300
350
400
0 100 200 300 400 500 600 700
WEIGHTOFSAMPLESCOLLECTEDFROMCVD
(MG)
TEMPERATURE (◦C)
2:01
3:04
1:03
3:02
Linear (2:01)

14. CHARACTERIZATION
• Morphology of CNTs produced were studied using SEM analysis.
• Shown that CNTs grown were varied according their
concentration ratio of bimetallic catalyst with their respective
temperature
• SEM images revealed the sizes of tube diameter and length of
the tubes

15. Concentration of Co: Mo with ratio 1:3 at temperature 400◦C
Concentration of Co: Mo with ratio 1:3 at temperature 600 ◦C
• No growth of CNTs
• Samples look like
accumulation of graphene
flakes
• Formation long aligned
Nano rods growth on the
sample
• Diameter range 273.7 nm
• Length range 12.4 µm

16. Concentration of Co: Mo with ratio 2:1 at temperature 400 ◦C
Concentration of Co: Mo with ratio 2:1 at temperature 600 ◦C
• Growth of disorder CNTs.
• Diameter range 64.2 nm
• Length range 13.5µm
• Formation long aligned
Nano rods growth on the
sample
• Diameter range 364.25 nm
• Length range 14.7µm

17. Concentration of Co: Mo with ratio 3:4 at temperature 400 ◦C
• Formation long aligned
Nano rods growth on the
sample
• Diameter range 197.7 nm
• Length range 10.6 µm

18. No. Co : Mo Temperature reduction (◦C) Average diameter (nm) Average length
(µm)
1 1:3 400 416.3 12.7
2 1:3 600 273.7 12.4
3 2:1 400 64.2 13.5
4 2:1 600 364.25 14.7
5 3:4 400 197.7 10.6
Table 2. Average diameter of CNTs from the selected samples
Temperature (◦C) Co : Mo CNT characteristics
400 1:3 No CNTs growth
600 1:3 Non-uniform, long aligned
400 2:1 Agglomeration “spaghetti’ like
600 2:1 Non-uniform, long aligned
400 3:4 Non-uniform, long aligned
Table 1. CNTs growth characteristics on substrate with various catalyst ratio and temperature

19. CONCLUSION
Curly and entangled CNTs were formed from the process. The best result
shown during the concentration ratio of bimetallic catalyst with 2:1 of Co
and Mo respectively at 400◦C. Average diameter of CNTs ranges from 43.0
nm to 78.6 nm.

20. RECOMENDATIONS
Through the observation of this study, the following recommendation is made for further works:
 Cooling of furnace after reaction by using electrical fan with round flexible duct. The time for cooling
may reduce from 14 hours to 10 hours.
 Leaking of gas reactors can be overcome by using keck clamp that apply on the external surface
between quartz tube and caps.
 Use variety of characterization for analysis sample such as XRD, FESEM and Uv-visible.
 Use design expert software to analyze the result.