Prof. Dr. Mohamed Khedr Dean of Beni Swef Faculty - postgraduate studies for Advanced Sciences

1. Carbon Age
Prof. Mohamed Khedr
Faculty of Postgraduates for advanced
Sciences, Beni-Suif University

2. Carbon
Melting point: ~ 3500oC
• Atomic radius: 0.077 nm
• Basis in all organic
componds
• 10 mill. carbon componds
•

3. Nanocarbon
•
•
•
•
•
•
•
•
•
Fullerene
Tubes
Cones
Carbon black
Horns
Rods
Foams
Nanodiamonds
Graphene
M. Khedr, A. Farghali, A. Moustafa and M. Zayed, International Journal of Nanoparticles, 2009, 2, 430-442.
M. Khedr, K. Abdel Halim and N. Soliman, Materials Letters, 2009, 63, 598-601.

4. Carbon black
Large industry
- mill. tons each year
•
Tires, black pigments,
plastics, dry-cell batteries,
UV-protection etc.
•
Size: 10 – 400 nm

5. Fullerene
”The most symmetrical large molecule”
• Discovered in 1985
- Nobel prize Chemistry 1996, Curl, Kroto, and Smalley
•
C60, also 70, 76 and 84.
- 32 facets (12 pentagons and 20 hexagons)
- prototype
Epcot center, Paris
~1 nm
Architect: R. Buckminster
Fuller

6. Graphene…….!!!
•• It's so strong of paper but a million times thinner. This
“Imagine a piece that It would take something
is how thick an elephant, balanced on a pencil,
the size of graphene is.
to break through a sheet of graphene the
• Imagine a material stronger than diamond. This is how
thickness of ais.
strong graphene piece of paper.
• Graphene is the strongest, yet thinnest possible material
you can imagine.

7. Allotropes of Carbon
Diamond, graphite, lonsdalerite, C60, C70,
carbon, amorphous carbon, carbon nanotube

8. What are carbon
nanotubes?
• Tubes with walls made of carbon (graphite)
• Nanometers in diameter
• Up to tens of micrometers in height
• Extremely good strength and field emission
properties

9. Classification of CNs:
single layer
• Single-wall Carbon nanotubes
(SWNTs,1993)
– one graphite sheet seamlessly wrapped-up to
form a cylinder
– typical radius 1nm, length up to mm
(10,10) tube
(From Dresselhaus et al., Physics World 1998)
(From R. Smalley´s web image gallery)

10. Classification of CNs:
ropes
• Ropes: bundles of SWNTs
– triangular array of individual SWNTs
– ten to several hundreds tubes
– typically, in a rope tubes of different diameters
and chiralities
(From R. Smalley´s web image gallery)
(From Delaney et al., Science 1998)

11. Classification of CNs:
many layers
• Multiwall nanotubes (Iijima 1991)
– russian doll structure, several inner shells
– typical radius of outermost shell > 10 nm
(From Iijima, Nature 1991)
(Copyright: A. Rochefort, Nano-CERCA, Univ. Montreal)

12. Why Carbon nanotubes so
interesting ?
• Technological applications
–
–
–
–
conductive and high-strength composites
energy storage and conversion devices
sensors, field emission displays
nanometer-sized molecular electronic devices
• Basic research: most phenomena of mesoscopic physics
observed in CNs
–
–
–
–
–
–
ballistic, diffusive and localized regimes in transport
disorder-related effects in MWNTs
strong interaction effects in SWNTs: Luttinger liquid
Coulomb blockade and Kondo physics
spin transport
superconductivity

13. Important History
• 1991 Discovery of multi-wall carbon nanotubes by S. Iijima
• 1992 Conductivity of carbon nanotubes J. W. Mintmire, B. I. Dunlap and C. T.
White
• 1993 Structural rigidity of carbon nanotubes G. Overney, W. Zhong, and D.
Tománek
• 1993 Synthesis of single-wall nanotubes by S Iijima and T Ichihashi
• 1995 Nanotubes as field emitters By A.G. Rinzler, J.H. Hafner, P. Nikolaev, L.
Lou, S.G. Kim, D. Tománek, P. Nordlander, D.T. Colbert, and R.E. Smalley
• 1997 Hydrogen storage in nanotubes A C Dillon, K M Jones, T A Bekkendahl, C
H Kiang, D S Bethune and M J Heben
• 1998 Synthesis of nanotube peapods B.W. Smith, M. Monthioux, and D.E. Luzzi
• 2000 Thermal conductivity of nanotubes Savas Berber, Young-Kyun Kwon, and
David Tománek
• 2001 Integration of carbon nanotubes for logic circuits P.C. Collins, M.S. Arnold,
and P. Avouris
• 2001 Intrinsic superconductivity of carbon nanotubes M. Kociak, A. Yu.
Kasumov, S. Guéron, B. Reulet, I. I. Khodos, Yu. B.
Gorbatov, V. T.
Volkov, L. Vaccarini, and H. Bouchiat

14. • Structure of carbon nanotubes
Classification of nanotube models, (a) armchair, (b) zigzag
and (c) chiral SWNTs.

15. Nanotube’s characteristic
•Seemless cylindrical molecules
•Diameter as small as 1 nm.
•Length: a few nm. to serveral micron
•As a monoelemental polymer: Carbon atoms
only
•As hexagonal network of carbon atoms
•CNTs are single molecules comprised of
rolled up graphene sheets capped at each
end.

16. Nanotube’s characteristic
• Young’s modulus of elasticity ~ 1 TPa
(Tera = 1012)
• Tensile strength > 60 GPa
(Steel ~ 2 GPa)
• Conductivity of CNTs ~ 109 A/cm2
(Copper 106 A/cm2 )

17. Applications
Lithium Ion
Batteries
Ultra
Capacitors
Charge Storage
M. Khedr, M. Bahgat, M. Radwan and H. Abdelmaksoud, Journal of materials processing technology, 2007, 190, 153-15
M. Bahgat, M. Khedr, M. Nasr and E. Sedeek, Metallurgical and Materials Transactions B, 2007, 38, 5-11

18. Applications
Plasma TV
Flat screen displays
M. Bahgat, M. Khedr, M. Nasr and E. Sedeek, Materials science and technology, 2006, 22, 315-320.
M. Khedr, M. Bahgat, M. Nasr and E. Sedeek, Colloids and surfaces A: Physicochemical and engineering aspects, 2007,
302, 517-524.

19. Applications
• Vacuum tubes
- Nobel prize 1906, Thomson.
• Semiconductor, Sibased
- Nobel prize 1956, Shockley,
Bardeen, and Brattain.
- 2000, Kilby.
IBM, 1952.
Transistor
M. Hessien and M. Khedr, Materials research bulletin, 2007, 42, 1242-1250.
K. S. Abdelahalim, A. M. Ismail, M. H. Khedr and M. F. Abadir, in First Afro-Asian Conference on Advanced Material
Technology, Nov. 13-16, Cairo - EGYPT, Editon edn., 2006.

20. Applications
Electric devices
K. Abdel Halim, M. Khedr, M. Nasr and A. El-Mansy, Materials research bulletin, 2007, 42, 731-741.
M. Khedr, M. Sobhy and A. Tawfik, Materials research bulletin, 2007, 42, 213-220.

21. Applications
2 H2(g) + O2(g) → 2 H2O (l) +
energy
Mg2NiH
LaNi5H
3.16 wt%
6
H2 (liquid)
H2 (200 bar)
1.37 wt%
Hydrogen storage
M. H. Khedr, A. A. Farghali and A. Abdel-Khalek, Journal of analytical and applied pyrolysis, 2007, 78, 1-6.
A. A. Farghali, M. H. Khedr and A. A. Abdel Khalek, Journal of materials processing technology, 2007, 181, 81-87.

22. Applications
Atomic Force Microscopy
M. Khedr, A. Omar and S. Abdel-Moaty, Materials Science and Engineering: A, 2006, 432, 26-33.
M. Khedr, A. Omar and S. Abdel-Moaty, Colloids and surfaces A: Physicochemical and engineering aspects, 2006, 281, 8

23. Current Applications
• Carbon Nano-tubes
are extending our
ability to fabricate
devices such as:
• Molecular probes
• Pipes
• Wires
• Bearings
• Springs
• Gears
• Pumps

24. Structural
clothes: waterproof tear-resistant
compat jackets: that use carbon nanotubes as ultrastrong fibers and to monitor the
condition of the wearer.
concrete: They increase the tensile strength, and halt crack propagation.
polyethylene: Researchers have found that adding them to increases the polymer's
elastic modulus by 30%.
sports equipment: Stronger and lighter tennis rackets, bike parts, golf balls, golf clubs,
golf shaft and baseball bats.
space elevator: This will be possible only if tensile strengths of more than about 70 GPa
can be achieved.
Bridges: For instance in suspension bridges (where they will be able to replace steel), or
bridges built as a "horizontal space elevator".

25. buckypaper- a thin sheet made from nanotubes that are 250 times stronger than steel and
10 times lighter that could be used as a heat sink for chipboards, a backlight
chemical nanowires: Carbon nanotubes additionally can also be used to produce
nanowires of other chemicals, such as gold or zinc oxide. These nanowires in turn can be
used to cast nanotubes of other chemicals, such as gallium nitride.
computer circuits: A nanotube formed by joining nanotubes of two different diameters
end to end can act as a diode.
conductive films: A 2005 paper in Science notes that drawing transparent high strength
swathes of SWNT is a functional production technique are developing transparent,
electrically conductive films of carbon nanotubes to replace indium tin oxide(ITO) in
LCDs, touch screens, and photovoltaic devices.

26. electric motor brushes: Conductive carbon nanotubes have been used for several years
in brushes for commercial electric motors. They replace traditional carbon black, which is
mostly impure spherical carbon fullerenes.
light bulb filament: alternative to tungsten filaments in incandescent lamps.
magnets: MWNTs coated with magnetite
optical ignition: A layer of 29% iron enriched SWNT is placed on top of a layer of explosive
material such as PETN, and can be ignited with a regular camera flash.
solar cells: GE's carbon nanotube diode has a photovoltaic effect. Nanotubes can replace
ITO in some solar cells to act as a transparent conductive film in solar cells to allow light to
pass to the active layers and generate photocurrent.
superconductor: Nanotubes have been shown to be superconducting at low temperatures.
ultracapacitors: MIT is researching the use of nanotubes bound to the charge plates of
capacitors in order to dramatically increase the surface area and therefore energy storage
ability.
displays: One use for nanotubes that has already been developed is as extremely fine
electron guns, which could be used as miniature cathode ray tubes in thin high-brightness
low-energy low-weight displays.
transistor: developed at Delft, IBM, and NEC.

27. Chemical
air pollution filter: Future applications of nanotube membranes include filtering carbon
dioxide from power plant emissions.
biotech container: Nanotubes can be opened and filled with materials such as
biological molecules, raising the possibility of applications in biotechnology.
hydrogen storage: Research is currently being undertaken into the potential use of
carbon nanotubes for hydrogen storage. They have the potential to store between 4.2
and 65% hydrogen by weight.
water filter: Recently nanotube membranes have been developed for use in filtration.
This technique can purportedly reduce desalination costs by 75%.
Mechanical
oscillator: fastest known oscillators (> 50 GHz).
nanotube membrane: Liquid flows up to five orders of magnitude faster than predicted
by classical fluid dynamics.
slick surface: slicker than Teflon and waterproof.

28. Properties
unusual current conduction mechanism: that make them ideal components of
electrical circuits. Currently, there is no reliable way to arrange carbon nanotubes into a
circuit.
The major hurdles that must be jumped for carbon nanotubes to find prominent places in
circuits relate to fabrication difficulties. The production of electrical circuits with carbon
nanotubes are very different from the traditional
IC fabrication process. The IC fabrication process is somewhat like sculpture - films
are deposited onto a wafer and pattern-etched away. Because carbon nanotubes are
fundamentally different from films, carbon nanotube circuits can so far not be mass
produced.
atomic force microscope in a painstaking, time-consuming process. Perhaps the best
hope is that carbon nanotubes can be grown through a chemical vapor deposition
process from patterned catalyst material on a wafer, which serve as growth sites and
allow designers to position one end of the nanotube. place the nanotubes from solution
to determinate place on a substrate.
Even if nanotubes could be precisely positioned, there remains the problem that, to this
date, engineers have been unable to control the types of nanotubes—metallic,
semiconducting, single-walled, multi-walled—produced. A chemical engineering solution
is needed if nanotubes are to become feasible for commercial circuits.

29. Production Methods
• Arc discharge
• Laser ablation
• Chemical Vapor Deposition
(CVD)

30. Arc–Discharge Process
• High-purity graphite rods
under a helium
atmosphere.
• T > 3000oC
• 20 to 40 V at a current in
the range of 50 to 100 A
• Gap between the rods
approximately 1 mm or
less
•Lots of impurities:
graphite, amorphous
carbon, fullerenes
Arc-discharge apparatus

31. Laser Ablation Process
• Temperature 1200oC
• Pressure 500 Torr
• Cu collector for carbon
clusters
• MWNT synthesized in
pure graphite
• SWNT synthesized
when Co, Ni, Fe, Y are
used
• Laminar flow
• Fewer side products
than Arc discharge
Laser ablation apparatus

32. CVD in Gas Phase Process
• Catalysts: Fe, Ni, Co, or alloys of the three metals
• Hydrocarbons: CH4, C2H2, etc.
• Temperature: First furnace 1050oC
Second furnace: 750oC
• Produce large amounts of MTWNs

33. Comparison of Nanotube
Production Technology

34. The CVD method has been reported to be the most selective in
CNTs formation
It can produce relatively large amounts of CNTs at lower cost
because it proceeds under mild conditions.
The CVD process makes it possible to control the purity of
product, the size and growth density of CNTs by regulating the
reaction parameters and catalyst composition as well as by
modifying .
The CNTs can also be readily isolated using chemical means
(HCl, HNO3, and HF), or ultra-sound treatment and heating.
it suitable for large area, irregular-shaped substrates and
multiple-substrate coatings,
It the most widely utilized duo to their versatility, and
industrial scalability

35. Controlling The yield %, and type of CNTs
• The yield %, and type of CNTs deposited depends on
support type ,percentage and type of metal loading, reaction
temperature, time, catalyst particles size, carrier gas flow
rate and finally the carbon source “ CO, CO2, CH4, C2H6,
C2H4 and C2H2”
• C2H2 exhibits very high carbon feed stock and very high
activity in producing metal carbide compared to CH4 and
CO
• Finally, acetylene is more reactive than other hydrocarbons
at the same reaction temperature, leading to CNTs of good
quality.

36. Selecting the materials of the present study;
•
Ferrites have continued to attract attention over years.
•
As magnetic materials, Ferrites cannot be replaced by any other
materials.
•
Ferrites are relatively inexpensive, stable and have a wide range of
technological applications in the fabrication of high quality filters, high
frequency circuits and operating devices.
•
Recently, ferrites are reported to be good catalysts for many chemical
processes. Among these processes, the decomposition of CO2 was
investigated as a process of both industrial and environmental
importance .
•
Because CO2 is a a major component of the greenhouse gases, which
caused the global worming, Freshly reduced copper ferrite was selected
as a catalyst for the decomposition of CO2.

40. CO2 Catalytic decomposition
Over freshly reduced CuFe2O4
• CO2 was allowed to decompose spontaneously
to carbon at 400-600oC during the reoxidation
of nano-crystallite metallic phase of Cu & Fe
compacts, produced from the reduction process.
• XRD analysis obtained for all samples
produced from the reduction-reoxidation
experiments at different temperatures indicates
that all samples contain the iron austenite and
magnetite phases, which reveals that CO2
decomposes during the reoxidation process to
carbon and oxygen forming the austenite and
magnetite.
•
Deposited carbon was detected by C-analysis.
•
Carbon in the form of Nano-tubes was detected
by SEM.
•
For more evidence, carbon nano-tubes were
isolated by suspention in acetone, TEM was
used to prove the formation of Carbon Nano-
200 nm

41. Production of
carbon nanotubes
using nanosized
metallic iron

42. • A catalyst of the composition 40%Fe2O3:60%Al2O3, was prepared by wet
impregnation method A certain amount of nanosized iron oxide powder was
mixed with Al2O3 powder and stirred for 1 hrs at 60 oC. The impregnate was
then dried in an oven at 100 oC for 3 hrs, calcined at 400 oC for 4 hrs in a box
muffle furnace.
• The catalysts was reduced at 500 oC at 1l/min in H2 flow and CNTs were
synthesized at the same reduction temperature by flowing 10%C2H2:90%H2
to know the most effective crystal size of iron oxide that give the highest
percentage yield of CNTs at 500 oC.

43. • The effect of growth temperature on the percentage yield was
also examined for iron oxide with crystal size 35 nm by
carrying out the acetylene decomposition reaction at
temperature 400, 500, 600 and 700 oC.
• The synthesized CNTs were cooled in H2 flow and the weight
of deposited CNTs was detected using weight gain technique.
•
C, % = (W1 – W2) / W2 ]*100
• where W2 is the initial weight of the catalyst (Fe ) and W1 is
the weight of carbon deposited and catalyst.
• The structure and morphology of the synthesized CNTs were
characterized using XRD and HTEM

44. 250
200
Carbon yield (%)
Samples of nanosized iron
oxides (supported in
alumina) were reduced
at 500 oC and subjected
to H2/C2H2 flow to get
the most effective
crystal size of the
catalyst that give the
highest percentage
yield of CNTs. The
highest percentage
yield (228 %) was
found for samples with
average crystal size of
35 nm.
150
100
35 nm
100 nm
150 nm
50
0
0
5
10
15
20
25
30
35
Time (min.)
Effect of crystal size of iron oxide catalyst on the Carbon
yield%

45. (a)
• TEM analysis of the produced
CNTs over iron produced from
the complete reduction of iron
oxide with crystal size 35nm
.Graphitic structures with a
central channel (CNTs) of internal
diameter 53-93 nm and its length
is about 1-10 µm and CNTs were
formed with a helix and curved
shape structure.
• The presence of catalytic
nanoparticles at the tip of the
produced CNTs suggests that the
TEM images of CNTs produced from the decomposition of
CNT production occurred via tip-acetylene over freshly reduced iron oxide with crystal size
35 nm at 500 C.
growth mechanism
1µm
(b
)
200 nm
o

46. • TEM image of carbon produced
from the decomposition of
acetylene over the iron
produced from the complete
reduction of iron oxide with
crystal size 150 nm shows that
A nonhomogeneity of the
carbon products was observed
(amorphous carbonaceous
0.5µm
structures) were observed in the
sample. It was also observed
that iron particles were kept in TEM images Carbon produced from the decomposition
of acetylene over freshly reduced iron oxide with crystal
carbon capsules.
size 150 nm at 500 C
• Generally, when metallic iron
particles increase in size, the
formation of nonselective forms
of carbon is favored.
o

47. 60
50
intensity (a.u )
40
( a)
30
20
10
0
100
80
Intensity (a.u )
XRD patterns of the catalysts after
acetylene decomposition shows
that there are two major peaks,
one is near 2θ = 26o Minor
asymmetric peak near 43.5o
indicating the well graphitized
nature of the CNT. The other
peaks are due to catalytic
impurities, metallic iron phases
and support (Al2O3 ). These
results suggest that the growth
mechanism of carbon nanotube
was the tip growth mechanism.
( b)
60
40
20
0
20
30
40
50
60
70
80
2-Theta scale
XRD patterns of iron oxide catalyst with average
crystal size 35 nm after decomposition of
acetylene at (a) 500 oC (b) 600 oC

48. A series of decomposition experiment were carried out at 400-700 oC using the iron
produced from the reduction of iron oxide samples with lowest crystal size (35 nm).
Two modes of decomposition rate can be observed. The first one at lower
decomposition temperature, 400 and 500 oC, where the percentage yield 220 % and
228 % was recorded, respectively. Increasing the temperature to 600 and 700 oC
increase in the decomposition rate and percentage yield of 426 and 407 % were
observed at 600 and 700 oC, respectively.
500
450
400
Carbon yield (%)
Carbon yield (%)
400
350
300
300
200
o
o
400 oC
500 oC
600 oC
700 C
100
250
0
200
350
0
400
450
500
550
600
650
700
750
5
10
15
20
25
30
35
Time (min.)
o
Decomposition temperature ( C)
the relation ship between the acetylene decomposition
temperature and the carbon yield % over freshly reduced iron
The effect of temperature on the catalytic decomposition
of acetylene over freshly reduced iron oxide with average
crystal size 35 nm

49. The activation energy value was found to be (12.5 kJ mol-1)
indicates that the decomposition of acetylene on the catalyst
surface is probably a physisorption process.
6
Ea =12.5 kJ/ mol
5
4
ln dr/dt
3
2
1
0
-1
-2
0.001
0.0011
0.0012
0.0013
1/T (k)
0.0014
0.0015
Fig. 11: Arrhenius plot of CNTs synthesis over freshly reduced nanosized Fe2O3

50. The presence of catalytic nano particles at the tip of the produced CNTs and its
appearance on the XRD- pattern suggests that the CNT production occurred
via a tip-growth mechanism where the supported metals particles detach and
move at the head of the growing nanotube
catalytic nano particles
TEM images of CNTs produced from the decomposition of
acetylene over freshly reduced iron oxide with crystal size
35 nm at 500 oC.

51. The rate is higher at the early stage then it
decrease with time and still active even
after 30 minutes of reaction which indicate
that the catalyst is very active toward the
decomposition of acetylene which is used as
a source of carbon

52. Kinetics of acetylene
decomposition over reduced
SHF
catalyst for the
production of carbon
nanotubes

53. •
Catalyst of the composition 40SHF:60Al2O3 is prepared by wet
impregnation method as follows: aqueous solutions of SHF with
the required amount, was mixed with Al2O3 powder and stirred for
1 hrs at 60 oC to remove dissolved oxygen and to achieve a
homogeneous impregnation of catalyst in the support. The
impregnate was then dried in an oven at 100 oC for 3 hrs, calcined
at 400 oC for 4 hrs in a box muffle furnace.
• Approximately 50 mg of a catalyst sample was introduced in to
cylindrical alumina cell closed with one end, the cell with the
catalyst placed in the central region of a longitudinal furnace.
• The catalyst was reduced at different temperature 500, 550, 600,
and 650 oC at 1l/min in H2 flow and CNTs were synthesized via two
type of experiments by flowing 10C2H2:90H2

54. E
N2

H2

C2H2
Reduction & decomposition system



55. • The synthesized CNTs were cooled in H2 flow and
the weight of deposited CNTs was detected using
weight gain technique.
• The activity of catalyst was measured by yield %
of carbon deposited which can be calculated from
the following relation,
C% = [W3 – (W1 – W2) / (W1 – W2)]*100.
• Where W1 is the initial weight of the catalyst, W2
is the weight loss of catalyst at operating
temperature, and W3 is the weight of carbon
deposited and catalyst.
• The structure and morphology of the synthesized
CNTs were characterized using high resolution
transmission electron microscopy (HRTEM)

56. Kinetics of acetylene decomposition over reduced
SHF catalyst for the production of CNTs
• The kinetics of synthesis of CNTs were
investigated through two types of experiments, the
first was done at constant reaction time 30 min and
rate gas flow of 10 C2H2: 90 H2, samples were
reduced at 500-650 oC and subjected to C2H2 flow
at each temperature. The optimum conditions for
the higher yield % were found to be 600 oC which
give 262.4 yield %
• The second type of experiments was done at
variable decomposition temperature 500-800 oC
and constant reduction temperature (600 oC). This
was done at the same experimental conditions. The
highest yield % was found at reduction and
decomposition temperature 600 and 700 oC
respectively.

57. Reaction temperature dependence for the yield % at variable
reduction and decomposition temperature.
yield % at (a) 500 oC, (b) 550 oC, (c) 600 oC, (d) 650 oC.

58. Not only CNTs but also CNFs
a
200nm
‫ــــــــــ‬


b
500nm



TEM images of CNFs produced on SHF reduced at
600 oC by the decomposition of acetylene at 500 oC.

59. Reduction temperature
) oC )
phases content
phases content
(%)
Crystal size
(nm)
500
Sr4Fe6O13,
Fe21.4O32,
FeO,
Fe (metal)
50
50
50
12.5
62.1
32.2
23.7
43.2
550
Fe (metal),
FeO,
Sr2Fe2O3
50
50
20.8
98.2
36.2
31.8
600
Fe (metal),
Fe21.4O32,
Fe2O3,
FeO,
Sr2Fe2O5,
SrO
50
6.25
10.4
6.25
6.1
4.17
104
20
77.6
Crystal size and the phase content for completely reduced SHF
compacts as obtained from XRD analysis.

60. • The activation energies for the first and second
experiments were found to be 26.3 and 5.2 kJ/mol
respectively,
Arrhenius plot of CNTs synthesis on reduced SHF supported
on alumina at different reduction temperature.

61. Arrhenius plot of CNTs synthesis on reduced SHF supported
on alumina at different decomposition temperature.

62. • Surface area measurements
• The catalyst has curie temperature around 500 oC, the catalyst
has different behaviors below and above these temperature.
Reduction temperature
500 oC
550 oC
600 oC
650 oC
Surface area
(m2g-1)
76.55
64.39
77.84
57.56
Total pore volume
( Ccg-1)
0.03788 0.0319
4
0.0368
0.02699
Average pore diameter
(nm)
19.79
18.91
18.76
Micro pore volume
(Ccg-1)
0.08814 0.0748
9
0.08045
0.0668
Adsorption energy
( kJmol-1)
2.429
2.357
2.217
19.84
2.208
The surface area measurements for the SHF supported on
alumina with the molar ratio 40 (SrFe12O19): 60Al2O3.

63. 200 nm

50nm
_____
TEM images of CNTs produced on SHF
reduced at 600 oC by the decomposition of
acetylene at 600 oC

64. Catalyst
Wt %
Time
(min)
T ( oC)
Carbon
source
Carrier
gas
Rate flow
Yield %
Observation
Fe-Ni/
MgO
2:98
30
1000
C2H2
N2
10:90cm3min
112
Good crystallinity
Fe-Ni/
MgO
2:98
60
800
C2H2
N2
10:90cm3min
104
Excellent quallity
Fe-Ni/
MgO
20:80
30
800
C2H2
N2
10:90cm3min
240
High quality and
density
Fe-Ni/
MgO
30:70
30
800
C2H2
N2
10:90cm3min
260
High quality and
density
Co-Mo/
MgO
5:95
30
800
C2H2
H2
10:100sccm
6
SWNTs
Co-Mo/
MgO
10:90
30
800
C2H2
H2
10:100sccm
27
Co-Mo/
MgO
40:60
30
800
C2H2
H2
10:100sccm
576
MWNTs
Fe/
AL2O3
40:60
90
700
C2H2
H2
10:100sccm
Low
L. 2m m D. 40-50 nm
Ni/
AL2O3
40:60
90
700
C2H2
H2
10:100sccm
Fe –Ni/
AL2O3
40:60
90
700
C2H2
H2
10:100sccm
121
L. 4 µ m D. 20 nm
Fe –Co/
CaCO3
5:95
60
700
C2H2/ C2H4
N2
30ml/min
358
Spongy and very soft
Fe –Co/
MgO
5:95
60
700
C2H2/ C2H4
N2
30ml/min
229

65. Catalyst
Carbon source
Temperature (oC)
Yield %
3Co:3Mo/SiO2
CO
800
1
1.7Co:85Mo/ MgO
CO
1000
2 SWNTs
1.7Co:85Mo/ MgO
CH4
1000
15 MWNTs
5Co:5Mo/ MgO
CH4
1000
80% SWNTs and
20% MWNTs
1Mo:9Fe/SiO2
CO
850
40
1Mo:9Fe/SiO2
C2H4
850
SWNTs and MWNTs
with a ratio of 3:7
Catalyst
Reduction
temperature
(oC)
Decomposition
temperature
(oC)
Freshly
reduced
500
500
171.3
SrFe12O19
550
550
272.3
30
supported on
Al2O3
Time
(min.)
Carbon
source
C2H2
Carrier
gas
H2
Rate
flow
L/min.
Yield
%
10/90
600
600
367
650
650
329

66. Second Experiment
Catalyst
Reductio
n
T (oC)
Freshly
reduced
Decompositio
n
T (oC)
Time Carbon
(min.) source
Carrie Rate Yield
r
flow
%
gas
L/min.
supported on
Al2O3
230.2
600
SrFe12
O19
500
367
600
30
C2H2
H2
10/90
700
436.9
800
180.7

67. Catalytic decomposition
of acetylene over
CoFe2O4/ BaFe12O19 core
shell

68. •
Catalyst of the composition 40 catalyst:60Al2O3 is prepared by
wet impregnation method as follows: aqueous solutions of catalyst
with the required amount, was mixed with Al2O3 powder and
stirred for 1 hrs at 60 oC to remove dissolved oxygen and to
achieve a homogeneous impregnation of catalyst in the support.
The impregnate was then dried in an oven at 100 oC for 3 hrs,
calcined at 400 oC for 4 hrs in a box muffle furnace.
• Approximately 50 mg of a catalyst sample was introduced in to
cylindrical alumina cell closed with one end, the cell with the
catalyst placed in the central region of a longitudinal furnace.
• The catalyst was reduced at different temperature 500, 600, 700
and 800 oC at 1l/min in H2 flow and CNTs were synthesized via
two type of experiments by flowing 10C2H2:90H2

69. 1. Catalyst characterization
The difference in reduction temperatures lead to difference in phases formed
during reduction process at those temperatures (500-800oC).
Figure 2. SEM of CoFe2O4 / BaFe12O19 core shell reduced, at
different temperatures, (A) 700 oC (81 % reduction)
(B) 500 oC (72 % reduction)
Figure 1 . XRD patterens for CoFe2O4/BaFe12O19 core shell reduced
at different temperatures
(1) Iron, Fe
(2) Cobalt, Co (3) Barium peroxide, BaO2
(4) Barium oxide, BaO .

70. 2. Surface area measurements
Table 1.
Effect of different reduction temperatures of CoFe2O4/ BaFe12O19 core shell on surface area measurements.
500 oC
600 oC
700 oC
800 oC
Surface area (m2/g)
82.24
124.1
66.96
36.29
Total pore volume (cc/g)
0.040
0.0629
0.032
0.018
Adsorption energy (kJ/mol)
2.58
2.9
2.342
2.250
Average pore diameter (nm)
19.83
20.29
19.38
19.95
Micro pore volume (cc/g)
0.077
0.105
0.0712
0.0429
Surface area increases by decreasing reduction temperatures till 600oC, then any further
decrease in temperatures from 600 to 500oC leads to a decrease in the surface area, as
shown in Figure which shows fine structure containing microspores of sample reduced
at 600oC.
Figure . SEM of CoFe2O4 / BaFe12O19 core shell
reduced at 600 oC.

71. 3. Effect of reduction temperature on the formation of carbon nanotubes
Figure . Carbon yields (%)
as a function of time at
different reduction and
decomposition
temperatures.

72. Figure . Carbon yields (%) as a function of temperatures of CoFe 2O4 / BaFe12O19 core shell reduced, at
different temperatures and decomposed the C2H2 at the same temperature.

73. Figure . TEM of CoFe2O4 / BaFe12O19 core shell reduced, at different temperatures,
(a) 700 oC (81 % reduction )
(b) 800 oC (84.5 % reduction)

74. Figure 5. TEM of CoFe2O4 / BaFe12O19 core shell reduced and decomposed the C2H2 at the same
temperature
(a) 700 oC ( 81 % reduction and 267% carbon yield )
(b) 500 oC ( 72 % reduction and 141% carbon yield )

75.  It is supposed that acetylene decomposes at different temperatures 500800°C on the top of a supported catalyst
 The dissolved carbon diffuses in the catalyst, precipitates on the rear
side and forms a nanotubes
 The carbon diffuses through the catalyst due to a thermal gradient
formed by the heat release of the exothermic decomposition of acetylene
 The formation of carbon nanotubes and formation of carbon fibers by tip
growth mode

76. 4. Effect of decomposition temperature on the formation of carbon
nanotubes and kinetics
Figure. Carbon yields (%) as a function of temperatures of CoFe2O4 / BaFe12O19
core shell reduced, at 700oC and decomposed the C2H2 at different temperatures
500-800 oC .

77. FT-IR spectra analysis at Figure , revealed four peaks at 283.48, 269.02, 256.48
and 1577.49 cm-1 that indicating the presence of multiwalled carbon nanotubes
as shown in the TEM micrograph.
Figure. FT-IR spectra for CoFe2O4 / BaFe12O19 core shell
reduced at 700oC and decomposed the C2H2 at 600oC
(a) at range from 4000-500cm -1 (b) at range from 650-150
cm-1
TEM of CoFe2O4 / BaFe12O19 core shell reduced at 700 oC
and decomposed the C2H2 at 600 oC.

78. Activation energy of 2.9
kJ/mol for the reaction
physisorption
Arrhenius plots for CoFe2O4/BaFe12O19 core shell reduced at different
temperatures 500- 800oC.

79. Catalytic
decomposition of
acetylene over
CoFe2O4/ NiFe2O4
core shell

80. 1. Catalyst characterization
The difference between reduction temperatures lead to slightly increase in the
rate of reduction from 76 % at 800 oC to 71% at 500 oC, which can be attributed to
grain size approximation.
SEM micrograph of cobalt ferrite /nickel
ferrite core shell reduced at different
temperatures at final stages at 600oC.
SEM micrograph of nanocrystallite
CoFe2O4 /NiFe2O4 core shell reduced at
800 oC.

81. 2. Surface area measurements
Effect of different reduction temperatures of CoFe2O4/ NiFe2O4 core shell on
surface area measurements
500 oC
600 oC
700 oC
800 oC
Surface area (m2/g)
193.8
65.09
74.79
185.7
Total pore volume (cc/g)
0.0968
0.032
0.0356
0.0690
Average pore diameter (nm)
19.99
19.67
19.08
14.87
Photomicrograph of CoFe2O4 / NiFe2O4 core shell reduced at 500 oC
(X400).

82. 3. Effect of reduction temperature on the formation of carbon nanotubes
Carbon yields
(%) as a
function of
time at
different
reduction and
decomposition
temperatures.

83. 4. Effect of decomposition temperature on the formation of carbon
nanotubes and kinetics
Carbon yields (%) as a
function of temperatures of
CoFe2O4 / NiFe2O4 core
shell reduced, at different
temperatures and
decomposed the C2H2 at
the same temperature.

84. Photomicrograph of
CoFe2O4 / NiFe2O4
core shell reduced at
different
temperatures (X40).
(a)800 oC to give 76
% reduction and 153
% carbon yield.
(b)700 oC to give 73
% reduction and 158
% carbon yield.
(c)600 oC to give 72
% reduction and 217
% carbon yield.
(d)500 oC to give 71
% reduction and 157
% carbon yield.

85. Carbon yields (%) as a
function of temperatures of
CoFe2O4 / NiFe2O4 core shell
reduced, at 600oC and
decomposed the C2H2 at
different temperatures 500800 oC.

86. TEM micrograph of cobalt ferrite /nickel ferrite core
shell reduced at 600oC and decomposition temperature at
700oC.
TEM micrograph of cobalt ferrite /nickel ferrite core shell reduced at 600oC and
decomposition temperature at 800oC.

87. FT-IR spectra analysis at Figure , revealed three peaks at 256.48, 1571.7 and
1282.43 cm-1 that indicating the presence of multiwalled carbon nanotubes as
shown in the TEM micrograph.
FT-IR spectra for CoFe2O4 / NiFe2O4 core shell reduced at 700oC and
decomposed the C2H2 at 600oC
(a) at range from 4000-500cm -1 (b) at range from 650-150 cm-1

88. physisorption
Activation energy of 2.1
kJ/mol for the reaction
Arrhenius plots for CoFe2O4/NiFe2O4
temperatures 500- 800oC.
core
shell
reduced
at
different

89. SYNTHESIS AND
MODIFICATION OF MULTI
WALLED CARBON
NANOTUBES (MWCNT) FOR
WATER TREATMENT
APPLICATIONS

90. 1- Preparation of C/S catalyst/support:
The support-catalyst were prepared by wet impregnation
method. A required amount of the support material (S)
was milled in a ball mill for 10 hrs in order to decrease
the crystallite size and increase the surface area.
Calculated ratios of the metal salts (C1(NO3)and C2(NO3)
were added into the ball mill with (S) and milled for
another 2 hrs. The produced fine powder dispersed in a
few drops of water, mixed well to get a homogeneous
paste of (S), C1(NO3) and C2(NO3). The mixture was
dried in oven at 120oC for 12 hrs, cooled and ground well
to obtain a fine powder of C1-C2/S catalyst/support
mixture

91. 2- Carbon nanotubes preparation:
Approximately 0.5g of catalyst/support sample was introduced to
cylindrical alumina cell closed with one end, the cell with the catalyst
suspended by chain in a horizontal furnace and attached to the pan of a
fully automatic sensitive (0.1 mg) balance (K) (Perciza-Swiss) to
record the weight gain at all the time of the experiment.
catalyst/support preheated to different operating temperature in a flow
of nitrogen gas (70 ml/min). After 10 min the acetylene gas was
allowed to pass over the catalyst bed with a rate of 10 ml/min for 40
min. The acetylene gas flow was stopped; the product on the alumina
cell was cooled to room temperature while nitrogen flow was on. The
weight of the carbon deposited along with the catalyst was noted. The
percentage of carbon deposit (C%) obtained in each reaction was
determined using the following relationship:
C % = [W3 – (W1 – W2) / (W1 – W2)]*100
where W1 is the initial weight of the catalyst , W2 is the weight loss of
catalyst at operating temperature, and W3 is the weight of carbon
deposited and catalyst.

92. 3- CNTs Purification:
CNTs purification process was achieved by using
Chemical oxidation method. Specific amount of the asgrown carbon nano-tubes were added to a mixture of
concentrated nitric acid /sulfuric acid (3:1 by volume,
respectively). The mixture is refluxed in oil bath for 4
hrs at 120 °C. After cooling to room temperature, the
reaction mixture is diluted with distilled water and then
filtered through a filter paper (3 μm porosity). This
washing operation was repeated several times using
distilled water and followed by drying in a drier at 100
°C.

93. 4-Adsorption of heavy metals and organic dyes:
Adsorption experiments were performed at 298 K.
Exactly 100 ml of metal or dye solution placed in a
beaker and 0.1g oxidized CNTs was added to the
solution and left on a magnetic stirrer for 5 min. to
ensure the dispersion. At different times, 5 ml of the
sample solution was withdrawn and filtered with filter
paper and the change in characteristic absorption at the
specific beaks measured using an ultraviolet-visible
(UV-vis) spectrophotometer (Jasco 530), from which the
concentration of heavy metals and dyes was inferred.

94. Results and dissections:
TEM image of the as prepared CNTs synthesized at 600 oC.
TEM image of the oxidized CNTs synthesized at
600 oC and refluxed in conc. Acid for 4 hrs.

95. SEM image of the oxidized CNTs synthesized at 600 oC and refluxed in concentrated acid for 4 hrs.

96. HNO3/H2SO4
MWCNT
Oxidized
b
MWCNT
schematic preparation of the functionalized carbon nanotubes.
a
b
FTIR spectra of (a) as grown MWNT , (b) acid treated purified MWNT.

97. 3
Before adsorption
After adsorption
Intensity
2
1
0
200
400
600
Wave length
Adsorption Mn7+ by using functionalized CNTs.
0.10
3
CrCl3 before adsorption
K2CrO4 after 4.5 hrs
CrCl3 after 8hrs
0.08
K2CrO4
CrCl3 after 3hrs
K2CrO4 after 20 hrs
2
Intensity
Intensity
0.06
0.04
1
0.02
0.00
0
-0.02
300
400
500
600
Wave length
700
800
300
400
500
600
Wave length
Absorption peaks of Cr3+ and Cr6+ adsorbed by functionalized CNTs.

98. 0.5
T. Blue
After adsorption
1
Methylen blue
Methylen blue after adsorption
0.4
Intensity
Intensity
0.3
0.2
0.0
0.0
300
0
400
500
600
700
300
800
400
500
600
700
800
Wave length
Wave length
Methyl green
Methyl green after adsorption
Intensity
Intensity
Bromopyrogallol red
Bromopyrogallol after adsorption
300
400
500
600
Wave length
700
800
300
400
500
600
700
800
Wave length
Absorption beaks of different dyes ( Tolludine blue,
Methyl green, Methylen blue, Bromopyrogallol red)
before and after adsorption on functionalized CNTs.

99. As-growing CNTs
Acid treated
Functionalized
HOOC
COOH
C=O
O=C
OH
HO
COOH
HOOC
COOH
Inner pores blocked
Catalyst removed
Adsorption increased
Functional group added
For nonpolar and/ or planer chemicals:
Adsorption decreased.
For polar chemicals : Adsorption increased.
The effect of CNT functional groups on organic molecule adsorption

101. Reduction-Reoxidation System

102. Activation energies of nano cryst. copper
ferrite reduction
1.5
initial
meddle
final
log(dr/dt)
1.0
0.5
0.0
-0.5
-1.0
11
12
13
14
104/T, K-1.
15
16

103. Gas-Solid reaction mechanisms
1-Gaseous diffusion mechanism
2-Interfacial chemical reaction mechanism
3-Solid state diffusion mechanism

104. Activation energies and controlling
mechanisms of the reduction process
Stage
Initial
Ea,
kJ/mol.
39.35
Controlling mechanism
Interfacial chemical reaction with
some contribution to gaseous
diffusion mechanism
Intermediate
Final
65.2
55.3
Interfacial chemical reaction
mechanism
Interfacial chemical reaction
mechanism

105. c
1 - (1-X)
1/2
1.0
0.8
0.6
0.4
0
50
100
150
200
250
time, min.
0.6
1 - (1-X)
1/2
b
0.5
0.4
0.3
0.2
1/2
[1-(1-X) ] + [X+(1-x) ln (1-X)]
0
20
40
60
80
100 120 140
time, min.
0.25
a
0.20
0.15
o
400 C
o
500 C
o
600 C
0.10
0.05
0.00
0
2
4
6
8
10 12 14 16 18 20
time, min.

106. CO2 Catalytic decomposition
Over freshly reduced 220 nm CuFe2O4
R6O6
• CO2 was allowed to decompose spontaneously
R6O5
to carbon at 400-600oC during the reoxidation
of nano-crystallite metallic phase of Cu & Fe
compacts, produced from the reduction process.
R6O4
produced from the reduction-reoxidation
experiments at different temperatures indicates
that all samples contain the iron austenite and
magnetite phases, which reveals that CO2
decomposes during the reoxidation process to
carbon and oxygen forming the austenite and
magnetite.
•
Deposited carbon was detected by C-analysis.
•
Carbon in the form of Nano-tubes was detected
by SEM.
•
For more evidence, carbon nano-tubes were
isolated by suspention in acetone, TEM was
used to prove the formation of Carbon Nano-
Intensity, a.u.
• XRD analysis obtained for all samples
R5O6
R5O5
R5O4
R4O6
R4O5
R4O4
20
30
40
50
60
2 - theta, degree
70
80