CARBON NANOMATERIALS SYNTHESIS, STRUCTURE, PROPERTIES AND APPLICATIONS CARBON NANOMATERIALS SYNTHESIS, STRUCTURE, PROPERTIES AND APPLICATIONS RAKESH BEHARI MATHUR BHANU PRATAP SINGH SHAILAJA PANDE Taylor & Francis Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2017 by Taylor & Francis Group, LLC Taylor & Francis is an Informa business No claim to original U.S. Government works Printed on acid-free paper Version Date: 20161109 International Standard Book Number-13: 978-1-4987-0210-2 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. 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CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging‑in‑Publication Data Names: Mathur, Rakesh Behari, 1952- author. | Singh, Bhanu Pratap (Scientist in Physics), author. | Pande, Shailaja, author. Title: Carbon nanomaterials : synthesis, structure, properties and applications / Rakesh Behari Mathur, Bhanu Pratap Singh, Shailaja Pande. Description: Boca Raton, FL : CRC Press, Taylor & Francis Group, [2016] Identifiers: LCCN 2016022639| ISBN 9781498702102 (hardback ; alk. paper) | ISBN 1498702104 (hardback ; alk. paper) | ISBN 9781498702119 (e-book) | ISBN 1498702112 (e-book) Subjects: LCSH: Nanostructured materials. | Carbon. | Nanotubes. Classification: LCC TA418.9.N35 M52135 2016 | DDC 620.1/15--dc23 LC record available at https://lccn.loc.gov/2016022639A Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Preface ...........................................................................................................................................xiii Authors ........................................................................................................................................xvii 1. Introduction to Carbon and Carbon Nanomaterials .......................................................1 1.1 Introduction ...................................................................................................................1 1.1.1 Atomic Structure of Carbon ...........................................................................3 1.1.2 Carbon Hybridization .....................................................................................5 1.1.3 Diamond Structure ..........................................................................................5 1.1.4 Graphite Structure ...........................................................................................6 1.2 Crystal Structure of Graphite ......................................................................................7 1.2.1 Two-Dimensional Lattice Structure: Unit Cell ............................................8 1.2.2 Reciprocal Lattice and Brillouin Zone ..........................................................9 1.3 Electronic Band Structure of Graphite .....................................................................10 1.3.1 Energy Dispersion Relation ..........................................................................10 1.3.2 Density of States .............................................................................................11 1.4 Physical Properties of Graphite .................................................................................12 1.4.1 Electrical Properties of Graphite..................................................................13 1.4.2 Mechanical Properties of Graphite .............................................................14 1.4.3 Thermal Properties of Graphite ...................................................................15 1.4.4 Chemical Properties of Graphite .................................................................16 1.5 Nongraphitic Carbons ................................................................................................17 1.5.1 Carbon Black ...................................................................................................18 1.5.2 Coal ..................................................................................................................18 1.5.3 Chars ................................................................................................................18 1.5.4 Graphitizing Carbons ....................................................................................18 1.5.5 Polycrystalline Graphite................................................................................19 1.6 Synthetic Carbon and Graphite.................................................................................20 1.6.1 Synthetic Graphite: Processing, Properties, and Applications ................21 1.6.2 Filler .................................................................................................................21 1.6.3 Binder...............................................................................................................22 1.6.4 Mesophase Pitch ............................................................................................22 1.6.5 Mixing and Blending ....................................................................................23 1.6.6 Carbonization .................................................................................................23 1.6.7 Graphitization ................................................................................................24 1.6.8 Structural Analysis of Carbons by X-Ray Diffraction ..............................25 1.7 Pyrolytic Carbon and Graphite .................................................................................28 1.7.1 Thermodynamics and Kinetics ....................................................................28 1.7.2 Isotropic and Laminar Deposits ..................................................................28 1.7.3 Graphitization of Columnar and Laminar Deposits ................................28 1.8 Nano Forms of Carbon ...............................................................................................29 1.8.1 Quantum Confinement in Carbon Nanomaterials ...................................30 1.8.2 Raman Spectroscopy of Nanocarbons ........................................................32 References ...............................................................................................................................38 Further Reading .....................................................................................................................39 v vi Contents 2. Fullerenes ...............................................................................................................................41 2.1 Introduction .................................................................................................................41 2.2 Discovery of Fullerenes ..............................................................................................42 2.3 Explosion in Fullerenes Research .............................................................................44 2.4 Methods of Synthesis of Fullerenes ..........................................................................45 2.4.1 Laser Vaporization Method ..........................................................................45 2.4.2 Resistive Heating of Graphite Electrodes ...................................................46 2.4.3 Electric Arc Discharge: Arc Heating or Arc Vaporization of Graphite Electrodes ...................................................................................47 2.4.4 Other Methods of Fullerene Synthesis .......................................................47 2.4.4.1 Pyrolysis ..........................................................................................47 2.4.4.2 Combustion of Hydrocarbons ......................................................48 2.4.4.3 Fullerene Synthesis Using Coal ....................................................48 2.4.4.4 Electron Beam Irradiation of Graphene under Transmission Electron Microscopy ..................................48 2.4.4.5 Solar Generators .............................................................................48 2.5 Purification, Isolation, and Characterization of Fullerenes ..................................49 2.5.1 Purification of Fullerene Soot.......................................................................49 2.5.2 Isolation of Fullerenes ...................................................................................50 2.5.3 Characterization of Fullerenes .....................................................................50 2.6 Formation Mechanism of Fullerenes .......................................................................53 2.7 Structure of Fullerenes ...............................................................................................54 2.7.1 Structures of Diamond, Graphite, and C .................................................54 60 2.7.2 Electronic Structure of C Fullerene ..........................................................56 60 2.7.3 Structure of Other Fullerenes ......................................................................57 2.7.4 Structure of Fullerite .....................................................................................58 2.8 Properties of Fullerenes .............................................................................................60 2.8.1 Physical Properties of Fullerenes ................................................................60 2.8.2 Chemical Properties and Reactions of Fullerenes ....................................60 2.8.2.1 Metal-Doped Fullerenes ................................................................61 2.8.2.2 Endohedral Metallofullerenes ......................................................62 2.8.2.3 Functionalized Fullerenes ............................................................64 2.9 Applications of Fullerenes .........................................................................................67 2.9.1 Superconductors.............................................................................................67 2.9.2 Organic Solar Cells ........................................................................................68 2.9.3 Biomedical and Personal Care Applications ..............................................68 2.9.3.1 Biomedical Applications ...............................................................68 2.9.3.2 Personal Care Applications...........................................................69 2.9.4 Biosensors .......................................................................................................69 References ...............................................................................................................................69 3. Single-Walled Carbon Nanotubes ....................................................................................75 3.1 History ..........................................................................................................................75 3.2 Structure of Single-Walled Carbon Nanotube (SWCNT) ......................................75 3.3 Synthesis of Carbon Nanotubes ................................................................................76 3.3.1 Arc Discharge .................................................................................................76 3.3.2 Laser Ablation ................................................................................................78 3.3.3 Chemical Vapor Deposition .........................................................................78 Contents vii 3.3.4 High-Pressure Carbon Monoxide Process .................................................79 3.3.5 Fluidized Bed .................................................................................................79 3.4 Growth Mechanism ....................................................................................................81 3.4.1 Growth Mechanism Based on Chemical Vapor Deposition ....................81 3.4.2 Mechanism of SWCNT Growth Using Arc Evaporation and Laser Ablation ...........................................................................................................82 3.5 Properties of SWCNTs ................................................................................................83 3.5.1 Mechanical Properties ..................................................................................84 3.5.2 Specific Gravity ..............................................................................................84 3.5.3 Thermal Conductivity ...................................................................................84 3.5.4 Electrical Conductivity .................................................................................84 3.6 Purification of SWCNTs .............................................................................................85 3.6.1 Acid Treatment ...............................................................................................85 3.6.2 Air Oxidation ..................................................................................................85 3.6.3 High Temperature Annealing ......................................................................85 3.7 Characterization of SWCNTs ....................................................................................85 3.7.1 Raman Spectroscopy .....................................................................................85 3.7.2 X-Ray Diffraction ...........................................................................................87 3.7.3 UV/Vis/NIR Spectroscopy of SWCNTs .....................................................87 3.8 Applications of Single-Walled Carbon Nanotubes ................................................89 3.8.1 Microelectronics .............................................................................................89 3.8.1.1 First SWCNT-Based Computer .....................................................90 3.8.2 Solar Cells .......................................................................................................91 3.8.3 Hydrogen Storage ..........................................................................................92 3.8.4 Biological and Biotechnological Applications ...........................................92 3.8.5 Space Elevator .................................................................................................92 References ...............................................................................................................................93 4. Multiwalled Carbon Nanotubes ........................................................................................97 4.1 Introduction .................................................................................................................97 4.2 Difference between Multiwalled Carbon Nanotubes (MWCNTs), Single- Walled Carbon Nanotubes (SWCNTs), and Carbon Nanofibers (CNFs) ......................................................................................................97 4.3 Synthesis of MWCNTs................................................................................................98 4.3.1 Arc Discharge .................................................................................................98 4.3.2 Laser Ablation ................................................................................................99 4.3.3 Chemical Vapor Deposition .........................................................................99 4.3.4 Fluidized Bed ...............................................................................................101 4.4 Purification and Functionalization.........................................................................102 4.5 Characterization ........................................................................................................103 4.5.1 Scanning Electron Microscopy ..................................................................103 4.5.2 High-Resolution Transmission Electron Microscopy .............................103 4.5.3 Raman Spectroscopy ...................................................................................103 4.5.4 Energy-Dispersive X-Ray Spectroscopy ...................................................107 4.5.5 Thermal Gravimetric Analysis ..................................................................107 4.6 Applications ...............................................................................................................108 4.6.1 Polymer Nanocomposites for Structural Applications ..........................108 4.6.2 CNT Yarn for Structural Composites........................................................109 viii Contents 4.6.3 Electrostatic Discharge and Electromagnetic Interference Shielding Applications ................................................................................110 4.6.4 CNTs as Anode Materials for Lithium-Ion Batteries ..............................111 4.6.5 Carbon Nanotubes in Fuel Cells ................................................................112 4.6.6 Water Purification ........................................................................................112 4.6.7 Armor Material ............................................................................................114 4.6.8 CNT as Self-Healing Material ....................................................................115 4.6.9 CNT-Based Conducting Cables .................................................................115 References .............................................................................................................................115 5. Carbon Nanofibers and Filaments ..................................................................................121 5.1 Introduction ...............................................................................................................121 5.2 Vapor-Grown Carbon Fibers ...................................................................................122 5.2.1 Historical Approach ....................................................................................122 5.3 Growth Mechanism ..................................................................................................123 5.3.1 Growth on Substrate ....................................................................................124 5.3.1.1 Temperature Gradient .................................................................125 5.3.1.2 Influence of Metal Support Interaction .....................................126 5.3.1.3 Diffusion Rate ...............................................................................126 5.3.1.4 Crystallographic Orientation ......................................................128 5.3.1.5 Why the Core Is Hollow ..............................................................128 5.4 Large-Scale Production: Gas Phase Process ..........................................................128 5.5 Morphology ...............................................................................................................131 5.5.1 As-Grown Vapor-Grown Carbon Fiber (VGCF) .....................................131 5.5.2 Heat-Treated VGCF ......................................................................................131 5.6 Mechanical Properties of VGCF .............................................................................133 5.7 Transport Properties of VGCF .................................................................................135 5.7.1 Electrical Conductivity ...............................................................................135 5.7.2 Thermal Conductivity .................................................................................136 5.8 Applications of VGCF ...............................................................................................136 5.8.1 Double-Layer Capacitor ..............................................................................137 5.8.2 Intercalation Compounds ...........................................................................137 5.8.3 Carbon Filaments in Reinforcement of Materials ...................................137 5.9 Graphite Whiskers ....................................................................................................137 5.9.1 Filaments Prepared from Carbon Arc ......................................................137 5.10 Carbon Nanofibers (CNFs) ......................................................................................138 5.10.1 Types of Carbon Nanofibers Available .....................................................139 5.10.2 Synthesis of Nanofibers ..............................................................................139 5.10.3 Growth and Morphology ............................................................................141 5.10.4 Heat Treatment .............................................................................................142 5.10.5 Intrinsic Fiber Conductivity .......................................................................142 5.10.6 Mechanical Properties of Nanofibers .......................................................142 5.11 Applications of Carbon Nanofiber .........................................................................143 5.11.1 Carbon Nanofiber Composites...................................................................143 5.11.2 Conductive Thermoplastic Composites ....................................................143 5.11.3 Electromagnetic Shielding..........................................................................144 5.11.4 Ablation Resistance .....................................................................................145 5.12 Carbon Microcoils and Nanocoils ..........................................................................145 References .............................................................................................................................146 Contents ix 6. Graphene and Graphene Oxide .......................................................................................149 6.1 Introduction ...............................................................................................................149 6.2 History of Graphene and Its Isolation ....................................................................150 6.3 Preparative Methods for Graphene ........................................................................152 6.3.1 Mechanical Exfoliation ...............................................................................152 6.3.2 Chemical Exfoliation of Graphite/Liquid-Phase Exfoliation of Graphite ....................................................................................................153 6.3.3 Chemical Exfoliation and Reduction of Exfoliated Graphite Oxide ....155 6.3.3.1 Synthesis of Graphite Oxide .......................................................156 6.3.3.2 Chemical Exfoliation of Graphite Oxide ...................................156 6.3.3.3 Reduction of Graphene Oxide ....................................................157 6.3.4 Chemical Vapor Deposition (CVD) ...........................................................158 6.3.5 Thermal Decomposition of Silicon Carbide .............................................160 6.4 Characterization of Graphene and Graphene Oxide ...........................................161 6.4.1 Optical Microscopy .....................................................................................161 6.4.2 Atomic Force Microscopy (AFM) ..............................................................161 6.4.3 Transmission Electron Microscopy (TEM) ...............................................163 6.4.4 Raman Spectroscopy ...................................................................................164 6.4.5 X-Ray Diffraction (XRD) .............................................................................167 6.5 Structure of Graphene, Graphite Oxide, and Graphene Oxide ..........................167 6.5.1 Structure of Graphene .................................................................................167 6.5.2 Structure of Graphite Oxide and Graphene Oxide .................................169 6.6 Properties of Graphene and Graphene Oxide .......................................................169 6.6.1 Electronic Properties of Graphene ............................................................169 6.6.1.1 Band Structure of Graphene .......................................................170 6.6.1.2 Electronic Properties of Graphene .............................................171 6.6.2 Mechanical Properties ................................................................................172 6.6.3 Optical Properties ........................................................................................173 6.6.4 Thermal Conductivity .................................................................................173 6.6.5 Chemical Reactivity of Graphene Oxide ..................................................173 6.7 Applications of Graphene and Graphene Oxide ..................................................176 6.7.1 Electronic Applications ...............................................................................176 6.7.2 Polymer Composites ....................................................................................177 References .............................................................................................................................178 7. Graphene Nanoribbons .....................................................................................................183 7.1 Introduction ...............................................................................................................183 7.2 Synthesis .....................................................................................................................183 7.2.1 Cutting from Graphene Using Lithography: Top-Down Approach .....184 7.2.2 Nanosphere Lithography ............................................................................185 7.2.3 Graphene Nanoribbon (GNR) Fabrication: Bottom-Up Approach .......187 7.2.4 Longitudinal Unzipping of Carbon Nanotubes Using Alkali Metal Vapor ..................................................................................................189 7.2.5 GNR by Unzipping of Carbon Nanotubes through Chemical Route ...191 7.3 Raman Spectroscopy of GNR ..................................................................................193 7.4 Potential Applications of GNR ................................................................................194 7.4.1 Electronics .....................................................................................................195 7.4.2 Graphene Transistors ..................................................................................195 7.4.3 Field-Effect Transistor Physics ...................................................................196