Graphene Chemistry

Dr De-en Jiang, Chemical Sciences Division, Oak Ridge National Laboratory, USADr Jiang has been working on computational study of graphene since 2006. In the past five years, he has published 15 papers in this topic which have been cited over 340 times. He has also written two book chapters on graphene-related topics. Using computational methods, he demonstrated the chemical reactivity of graphene's zigzag edge and showed the critical size for the onset of magnetism in nanographenes. Together with his colleagues, he was also the first to show a proof of concept for the extraordinary gas-separating power of porous graphene. Dr Zhongfang Chen, Department of Chemistry, University of Puerto Rico, San JuanDr Chen is a computational chemist and computational nanomaterials scientist. He has published over 140 papers or book chapters and his papers have been cited more than 3200 times, giving him an h-index of 31. Nine papers have been highlighted by news media (Chem. & Eng. News and/or Nachrichten aus der Chemie, Nature China) and one article was featured by Nature Chemistry. Dr Chen has been involved in research on carbon graphene and its non-carbon analogues since 2008, and has published around 20 papers in this field so far. He is investigating the intrinsic properties of pristine and functionalized carbon and non-carbon graphenes, and exploring their applications in nanoelectronics, nanocatalysis and nanosensors.

• List of Contributors xvPreface xixAcknowledgements xxi1 Introduction 1De-en Jiang and Zhongfang Chen2 Intrinsic Magnetism in Edge-Reconstructed Zigzag Graphene Nanoribbons 9Zexing Qu and Chungen Liu2.1 Methodology 102.1.1 Effective Valence Bond Model 102.1.2 Density Matrix Renormalization Group Method 112.1.3 Density Functional Theory Calculations 122.2 Polyacene 122.3 Polyazulene 142.4 Edge-Reconstructed Graphene 172.4.1 Energy Gap 172.4.2 Frontier Molecular Orbitals 182.4.3 Projected Density of States 192.4.4 Spin Density in the Triplet State 202.5 Conclusion 22Acknowledgments 23References 233 Understanding Aromaticity of Graphene and Graphene Nanoribbons by the Clar Sextet Rule 29Dihua Wu, Xingfa Gao, Zhen Zhou, and Zhongfang Chen3.1 Introduction 293.1.1 Aromaticity and Clar Theory 303.1.2 Previous Studies of Carbon Nanotubes 333.2 Armchair Graphene Nanoribbons 343.2.1 The Clar Structure of Armchair Graphene Nanoribbons 343.2.2 Aromaticity of Armchair Graphene Nanoribbons and Band Gap Periodicity 373.3 Zigzag Graphene Nanoribbons 403.3.1 Clar Formulas of Zigzag Graphene Nanoribbons 403.3.2 Reactivity of Zigzag Graphene Nanoribbons 403.4 Aromaticity of Graphene 423.5 Perspectives 44Acknowledgements 45References 454 Physical Properties of Graphene Nanoribbons: Insights from First-Principles Studies 51Dana Krepel and Oded Hod4.1 Introduction 514.2 Electronic Properties of Graphene Nanoribbons 534.2.1 Zigzag Graphene Nanoribbons 534.2.2 Armchair Graphene Nanoribbons 564.2.3 Graphene Nanoribbons with Finite Length 584.2.4 Surface Chemical Adsorption 604.3 Mechanical and Electromechanical Properties of GNRs 634.4 Summary 66Acknowledgements 66References 665 Cutting Graphitic Materials: A Promising Way to Prepare Graphene Nanoribbons 79Wenhua Zhang and Zhenyu Li5.1 Introduction 795.2 Oxidative Cutting of Graphene Sheets 805.2.1 Cutting Mechanisms 805.2.2 Controllable Cutting 835.3 Unzipping Carbon Nanotubes 855.3.1 Unzipping Mechanisms Based on Atomic Oxygen 865.3.2 Unzipping Mechanisms Based on Oxygen Pairs 885.4 Beyond Oxidative Cutting 915.4.1 Metal Nanoparticle Catalyzed Cutting 925.4.2 Cutting by Fluorination 955.5 Summary 96References 966 Properties of Nanographenes 101Michael R. Philpott6.1 Introduction 1016.2 Synthesis 1036.3 Computation 1036.4 Geometry of Zigzag-Edged Hexangulenes 1046.5 Geometry of Armchair-Edged Hexangulenes 1076.6 Geometry of Zigzag-Edged Triangulenes 1106.7 Magnetism of Zigzag-Edged Hexangulenes 1126.8 Magnetism of Zigzag-Edged Triangulenes 1146.9 Chimeric Magnetism 1156.10 Magnetism of Oligocenes, Bisanthene-Homologs, Squares and Rectangles 1176.10.1 Oligocene Series: C4m+2H2m+4 (na=1; m=2, 3, 4 . . .) 1176.10.2 Bisanthene Series: C8m+4H2m+8 (na 3; m=2, 3, 4 . . .) 1196.10.3 Square and Rectangular Nano-Graphenes: C8m+4H2m+8 (m=2, 3, 4 . . .) 1226.11 Concluding Remarks 122Acknowledgment 123References 1247 Porous Graphene and Nanomeshes 129Yan Jiao, Marlies Hankel, Aijun Du, and Sean C. Smith7.1 Introduction 1297.1.1 Graphene-Based Nanomeshes 1307.1.2 Graphene-Like Polymers 1307.1.3 Other Relevant Subjects 1317.1.3.1 Isotope Separation 1317.1.3.2 Van der Waals Correction for Density Functional Theory 1327.1.3.3 Potential Energy Surfaces for Hindered Molecular Motions Within the Narrow Pores 1337.2 Transition State Theory 1347.2.1 A Brief Introduction of the Idea 1347.2.2 Evaluating Partition Functions: The Well-Separated “Reactant” State 1367.2.3 Evaluating Partition Functions: The Fully Coupled 4D TS Calculation 1377.2.4 Evaluating Partition Functions: Harmonic Approximation for the TS Derived Directly from Density Functional Theory Calculations 1387.3 Gas and Isotope Separation 1397.3.1 Gas Separation and Storage by Porous Graphene 1397.3.1.1 Porous Graphene for Hydrogen Purification and Storage 1397.3.1.2 Porous Graphene for Isotope Separation 1407.3.2 Nitrogen Functionalized Porous Graphene for Hydrogen Purification/Storage and Isotope Separation 1407.3.2.1 Introduction 1407.3.2.2 NPG and its Asymmetrically Doped Version for D2/H2 Separation – A Case Study 1417.3.3 Graphdiyne for Hydrogen Purification 1447.4 Conclusion and Perspectives 147Acknowledgement 147References 1478 Graphene-Based Architecture and Assemblies 153Hongyan Guo, Rui Liu, Xiao Cheng Zeng, and Xiaojun Wu8.1 Introduction 1538.2 Fullerene Polymers 1548.3 Carbon Nanotube Superarchitecture 1568.4 Graphene Superarchitectures 1608.5 C60/Carbon Nanotube/Graphene Hybrid Superarchitectures 1638.5.1 Nanopeapods 1638.5.2 Carbon Nanobuds 1658.5.3 Graphene Nanobuds 1688.5.4 Nanosieves and Nanofunnels 1698.6 Boron-Nitride Nanotubes and Monolayer Superarchitectures 1718.7 Conclusion 173Acknowledgments 173References 1749 Doped Graphene: Theory, Synthesis, Characterization, and Applications 183Florentino López-Urías, Ruitao Lv, Humberto Terrones, and Mauricio Terrones9.1 Introduction 1839.2 Substitutional Doping of Graphene Sheets 1849.3 Substitutional Doping of Graphene Nanoribbons 1949.4 Synthesis and Characterization Techniques of Doped Graphene 1969.5 Applications of Doped Graphene Sheets and Nanoribbons 2009.6 Future Work 201Acknowledgments 202References 20210 Adsorption of Molecules on Graphene 209O. Leenaerts, B. Partoens, and F. M. Peeters10.1 Introduction 20910.2 Physisorption versus Chemisorption 21010.3 General Aspects of Adsorption of Molecules on Graphene 21210.4 Various Ways of Doping Graphene with Molecules 21510.4.1 Open-Shell Adsorbates 21510.4.2 Inert Adsorbates 21710.4.3 Electrochemical Surface Transfer Doping 22010.5 Enhancing the Graphene-Molecule Interaction 22110.5.1 Substitutional Doping 22110.5.2 Adatoms and Adlayers 22210.5.3 Edges and Defects 22410.5.4 External Electric Fields 22410.5.5 Surface Bending 22510.6 Conclusion 226References 22611 Surface Functionalization of Graphene 233Maria Peressi11.1 Introduction 23311.2 Functionalized Graphene: Properties and Challenges 23611.3 Theoretical Approach 23711.4 Interaction of Graphene with Specific Atoms and Functional Groups 23811.4.1 Interaction with Hydrogen 23811.4.2 Interaction with Oxygen 24011.4.3 Interaction with Hydroxyl Groups 24111.4.4 Interaction with Other Atoms, Molecules, and Functional Groups 24511.5 Surface Functionalization of Graphene Nanoribbons 24711.6 Conclusions 248References 24912 Mechanisms of Graphene Chemical Vapor Deposition (CVD) Growth 255Xiuyun Zhang, Qinghong Yuan, Haibo Shu, and Feng Ding12.1 Background 25512.1.1 Graphene and Defects in Graphene 25512.1.2 Comparison of Methods of Graphene Synthesis 25712.1.3 Graphene Chemical Vapor Deposition (CVD) Growth 25712.1.3.1 The Status of Graphene CVD Growth 25712.1.3.2 Phenomenological Mechanism 26012.1.3.3 Challenges in Graphene CVD Growth 26012.2 The Initial Nucleation Stage of Graphene CVD Growth 26112.2.1 C Precursors on Catalyst Surfaces 26212.2.2 The sp C Chain on Catalyst Surfaces 26212.2.3 The sp2 Graphene Islands 26312.2.4 The Magic Sized sp2 Carbon Clusters 26412.2.5 Nucleation of Graphene on Terrace versus Near Step 26612.3 Continuous Growth of Graphene 27112.3.1 The Upright Standing Graphene Formation on Catalyst Surfaces 27112.3.2 Edge Reconstructions on Metal Surfaces 27312.3.3 Growth Rate of Graphene and Shape Determination 27512.3.4 Nonlinear Growth of Graphene on Ru and Ir Surfaces 27612.4 Graphene Orientation Determination in CVD Growth 27812.5 Summary and Perspectives 280References 28213 From Graphene to Graphene Oxide and Back 291Xingfa Gao, Yuliang Zhao, and Zhongfang Chen13.1 Introduction 29113.2 From Graphene to Graphene Oxide 29213.2.1 Modeling Using Cluster Models 29213.2.1.1 Oxidative Etching of Armchair Edges 29213.2.1.2 Oxidative Etching of Zigzag Edges 29313.2.1.3 Linear Oxidative Unzipping 29413.2.1.4 Spins upon Linear Oxidative Unzipping 29613.3 Modeling Using PBC Models 29713.3.1 Oxidative Creation of Vacancy Defects 29713.3.2 Oxidative Etching of Vacancy Defects 29813.3.3 Linear Oxidative Unzipping 29913.3.4 Linear Oxidative Cutting 30013.4 From Graphene Oxide back to Graphene 30213.4.1 Modeling Using Cluster Models 30213.4.1.1 Cluster Models for Graphene Oxide 30213.4.1.2 Hydrazine De-Epoxidation 30213.4.1.3 Thermal De-Hydroxylation 30713.4.1.4 Thermal De-Carbonylation and De-Carboxylation 30813.4.1.5 Temperature Effect on De-Epoxidation and De-Hydroxylation 30913.4.1.6 Residual Groups of Graphene Oxide Reduced by Hydrazine and Heat 31113.4.2 Modeling Using Periodic Boundary Conditions 31213.4.2.1 Hydrazine De-Epoxidation 31213.4.2.2 Thermal De-Epoxidation 31313.5 Concluding Remarks 314Acknowledgement 314References 31414 Electronic Transport in Graphitic Carbon Nanoribbons 319Eduardo Costa Girão, Liangbo Liang, Jonathan Owens, Eduardo Cruz-Silva, Bobby G. Sumpter, and Vincent Meunier14.1 Introduction 31914.2 Theoretical Background 32014.2.1 Electronic Structure 32014.2.1.1 Density Functional Theory 32014.2.1.2 Semi-Empirical Methods 32014.2.2 Electronic Transport at the Nanoscale 32214.3 From Graphene to Ribbons 32414.3.1 Graphene 32414.3.2 Graphene Nanoribbons 32514.4 Graphene Nanoribbon Synthesis and Processing 32914.5 Tailoring GNR’s Electronic Properties 33014.5.1 Defect-Based Modifications of the Electronic Properties 33114.5.1.1 Non-Hexagonal Rings 33114.5.1.2 Edge and Bulk Disorder 33214.5.2 Electronic Properties of Chemically Doped Graphene Nanoribbons 33214.5.2.1 Substitutional Doping of Graphene Nanoribbons 33214.5.2.2 Chemical Functionalization of Graphene Nanoribbons 33314.5.3 GNR Assemblies 33414.5.3.1 Nanowiggles 33414.5.3.2 Antidots and Junctions 33514.5.3.3 GNR Rings 33514.5.3.4 GNR Stacking 33614.6 Thermoelectric Properties of Graphene-Based Materials 33614.6.1 Thermoelectricity 33614.6.2 Thermoelectricity in Carbon 33614.7 Conclusions 338Acknowledgements 339References 33915 Graphene-Based Materials as Nanocatalysts 347Fengyu Li and Zhongfang Chen15.1 Introduction 34715.2 Electrocatalysts 34715.2.1 N-Graphene 34815.2.2 N-Graphene-NP Nanocomposites 35015.2.3 Non-Pt Metal on the Porphyrin-Like Subunits in Graphene 35115.2.4 Graphyne 35215.3 Photocatalysts 35315.3.1 TiO2-Graphene Nanocomposite 35315.3.2 Graphitic Carbon Nitrides (g-C3N4) 35515.4 CO Oxidation 35615.4.1 Metal-Embedded Graphene 35715.4.2 Metal-Graphene Oxide 35815.4.3 Metal-Graphene under Mechanical Strain 35915.4.4 Metal-Embedded Graphene under an External Electric Field 36015.4.5 Porphyrin-Like Fe/N/C Nanomaterials 36115.4.6 Si-Embedded Graphene 36115.4.7 Experimental Aspects 36115.5 Others 36215.5.1 Propene Epoxidation 36215.5.2 Nitromethane Combustion 36215.6 Conclusion 363Acknowledgements 364References 36416 Hydrogen Storage in Graphene 371Yafei Li and Zhongfang Chen16.1 Introduction 37116.2 Hydrogen Storage in Molecule Form 37316.2.1 Hydrogen Storage in Graphene Sheets 37316.2.2 Hydrogen Storage in Metal Decorated Graphene 37416.2.2.1 Lithium Decorated Graphene 37516.2.2.2 Calcium Decorated Graphene 37616.2.2.3 Transition Metal Decorated Graphene 37716.2.3 Hydrogen Storage in Graphene Networks 37716.2.3.1 Covalently Bonded Graphene 37816.2.4 Notes to Computational Methods 38116.3 Hydrogen Storage in Atomic Form 38216.3.1 Graphane 38216.3.2 Chemical Storage of Hydrogen by Spillover 38316.4 Conclusion 386Acknowledgements 386References 38617 Linking Theory to Reactivity and Properties of Nanographenes 393Qun Ye, Zhe Sun, Chunyan Chi, and Jishan Wu17.1 Introduction 39317.2 Nanographenes with Only Armchair Edges 39417.3 Nanographenes with Both Armchair and Zigzag Edges 39717.3.1 Structure of Rylenes 39817.3.2 Chemistry at the Armchair Edges of Rylenes 39817.3.3 Anthenes and Periacenes 40217.4 Nanographene with Only Zigzag Edges 40517.4.1 Phenalenyl-Based Open-Shell Systems 40617.5 Quinoidal Nanographenes 41117.5.1 Bis(Phenalenyls) 41217.5.2 Zethrenes 41417.5.3 Indenofluorenes 41717.6 Conclusion 417References 41818 Graphene Moiré Supported Metal Clusters for Model Catalytic Studies 425Bradley F. Habenicht, Ye Xu, and Li Liu18.1 Introduction 42518.2 Graphene Moiré on Ru(0001) 42618.3 Metal Cluster Formation on g/Ru(0001) 43018.4 Two-dimensional Au Islands on g/Ru(0001) and its Catalytic Activity 43418.5 Summary 440Acknowledgments 441References 441Index 447