Synthesis of Carbon Nanotubes

Presented by

Ms. Anita Gopalkrishna Sharma

Under the guidance of

Dr. A. W. Patwardhan and Prof. J. B. Joshi

Synthesis of Carbon Nanotubes

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Outline

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Introduction

Literature Survey

Plan of Action

Studies in Fixed Bed

Actual Work

Analysis of N-CNTs

Hydrogen Storage

Problems Encountered

Fluidized bed

Literature Survey

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Based on CVD method of doping N on CNTs

Different Application of N-CNTs

Hydrogen Storage on N-CNTs

CVD Synthesis of N-CNTs

Add Tables

Author Year Type of CNT Catalyst/SupportC-source N-SourceType of reactor used Atom%Time of reac.(min) Nath .M et al. 2000MWNTs Fe/Si Pyridine Pyridine Fixed Bed ---- 30Terrones et al. 2002MWNTs Ferrocene/Silica Melamine Melamine Fixed Bed 2 to 1030Liu .J et al. 2004MWNT Ferrocene Pyridine or Pyrolidine Pyridine or Pyrolidine Horizontal quartz tube 1 to 260Maiyalagan,T et al. 2005MWNT Alumina Membrane Dichloro Methane Polyvinyla pyrolidine Fixed Bed 3180Ghosh . K et al. 2010MWNTs Ferrocene/Si Imidazole Imidazole Fixed Bed 12.1-25.7 15Huang .J. Q et al. 2012MWNT Fe-Mo/Vermiculite Acetylene Ammonia Fluidised Bed 1.55-4.23 30Hong .W.M et al. 2013SWNT Fe-Mo/MgO Methane Ammonia Fixed Bed 2.5130Betancourt M.C et al. 2014MWNT Ferrocene/SiO2 Benzylamine Benzylamine Fixed Bed ------ 30

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Application of N-CNTs

Author Year Nitrogen Source Application Mayalagan . T. 2008Polyvinylpyrolidone Electrocatalytic activity of methanol oxidation Ci .S. et al. 2012Ethylene Diamine Microbial Fuel Cells Adjizian et al. 2013Benzylamine Gas Detection Chen. L .et al. 2013Melamine Hydrogen Storage Yu.C. et al. 2013As-synthesized Photodegradation of dyes Chen.C. et al. 2013As-synthesized Catalyst in oxidative dehydrogenation of propane

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Hydrogen Storage in N-CNTs

AuthorYearType of CNTPreparation MethodC-sourceDopingAtom%Wt% of hydrogen storedTemp of storagePress. Of storageChen L., et al.2013MWNTPyrolysisMelamineNitrogen1.51.21777Chen L., et al.2013MWNTPyrolysisMelamineNitrogen1.50.1729819Rangel et al2009SWNTDensity functional theoryDensity functional theoryDensity functional theory14.69.8771Rangel et al2009SWNTDensity functional theoryDensity functional theoryDensity functional theory14.663001Silambarasan, D. et al.2014SWNTAs synthesized CNTAs synthesized CNTBoron1.54.773231

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Plan of action

Synthesis of N-CNTs in Fixed bed using a floating catalyst and a prepared catalyst.

Increasing the yield of CNTs by using additional source along with Imidazole

Kinetics of the reaction

Applying the kinetics of the process for bulk synthesis in a fluidized bed

Characterization of N-CNTs using different analytical techniques.

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F

A

M

I

S

R

Q

O

T

A: Acetylene GasF: Furnace Q: Quartz Tube O: Outlet Gas

I: Argon GasR: Imidazole & Ferrocene S: Magnesium oxide

M: Mixed Stream T: Temperature ControllerC1,C2: Flow Controller

Z1: Zone 1Z2: Zone 2D: Distributor

C2

C1

Fixed Bed for preparing N-doped CNTs

Furnace used is two zone furnace

Length and Diameter of Quartz tube is 1500mm and 65mm respectively

Temperature: 900oC

Total Flow rate: 100 sccm

Reactant : Catalyst = 19:1

Z1

Z2

D

Fluidized Bed Reactor

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Reactions were carried out at 175 sccm using the same ratio of catalyst to reactant as in the other cases.

Minimum fluidization velocity was observed to be around 4.19 mm/s and that calculated from Archimedes number considering agglomerate size to be 60m was 4.21mm/s.

Yield obtained = 1.2 g for 4 g of reactant.

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Kinetics of the process

Studies using Taguchi method for experimental design

Conclusion could not be drawn clearly so detailed kinetic study was required.

DOE 1DOE 2DOE 3Temperature (C)7008501000Flow Rate (sccm)355075Amount of Catalyst (g)0.2510.5Yield (g)0.0570.20.09

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Temperature studies

Reactant: Imidazole(4g) Acetylene (25sccm)

Catalyst:

Ferrocene

Inert Gas: Argon(75sccm)

Activation Energy 160 KJ/mol

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Reaction rate Versus Temperature

y = -19245x + 14.071R = 0.9847

1.1452785890167798E-31.0275908133381285E-39.7737379660851388E-49.3183618319899473E-48.9035302497440403E-48.5240591569705495E-4-8.0505387859633846-5.598421958998375-4.5232299445383672-4.2692860117184326-2.7850112422383413-2.4449739394526282

Observations

Lower Temperature Lower yield.

Maximum Yield Obtained at 900C which was about 1.6 g.

Yield decreased at 950C due to the formation of amorphous carbon.

More amorphous carbon found when acetylene used as a gas source.

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Flow rate studies

Considering mass transfer over flat plate,

Sh= 0.664 (Re)0.5 (Sc)0.33

Re =6. 128 .. (Laminar flow)

Sc =0.653

Sh=1.426

kL = 1.78 *10-4 m/s

Considering the surface of the catalyst, it can be said that,

Flux to the surface = rate of reaction on the surface

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So that kL [CA0-CAs] = kR CA0

If the kinetics of the reaction is surface reaction controlled then

rA = kLkRCA0/ kR+kL

Substituting all the known values the value of kR calculated is

kR = 5.45 * 10-6