Graphene Chemistry

Preface xix Acknowledgements xxi 1 Introduction 1 De-en Jiang and Zhongfang Chen 2 Intrinsic Magnetism in Edge-Reconstructed Zigzag Graphene Nanoribbons 9 Zexing Qu and Chungen Liu 2.1 Methodology 10 2.1.1 Effective Valence Bond Model 10 2.1.2 Density Matrix Renormalization Group Method 11 2.1.3 Density Functional Theory Calculations 12 2.2 Polyacene 12 2.3 Polyazulene 14 2.4 Edge-Reconstructed Graphene 17 2.4.1 Energy Gap 17 2.4.2 Frontier Molecular Orbitals 18 2.4.3 Projected Density of States 19 2.4.4 Spin Density in the Triplet State 20 2.5 Conclusion 22 Acknowledgments 23 References 23 3 Understanding Aromaticity of Graphene and Graphene Nanoribbons by the Clar Sextet Rule 29 Dihua Wu, Xingfa Gao, Zhen Zhou, and Zhongfang Chen 3.1 Introduction 29 3.1.1 Aromaticity and Clar Theory 30 3.1.2 Previous Studies of Carbon Nanotubes 33 3.2 Armchair Graphene Nanoribbons 34 3.2.1 The Clar Structure of Armchair Graphene Nanoribbons 34 3.2.2 Aromaticity of Armchair Graphene Nanoribbons and Band Gap Periodicity 37 3.3 Zigzag Graphene Nanoribbons 40 3.3.1 Clar Formulas of Zigzag Graphene Nanoribbons 40 3.3.2 Reactivity of Zigzag Graphene Nanoribbons 40 3.4 Aromaticity of Graphene 42 3.5 Perspectives 44 Acknowledgements 45 References 45 4 Physical Properties of Graphene Nanoribbons: Insights from First-Principles Studies 51 Dana Krepel and Oded Hod 4.1 Introduction 51 4.2 Electronic Properties of Graphene Nanoribbons 53 4.2.1 Zigzag Graphene Nanoribbons 53 4.2.2 Armchair Graphene Nanoribbons 56 4.2.3 Graphene Nanoribbons with Finite Length 58 4.2.4 Surface Chemical Adsorption 60 4.3 Mechanical and Electromechanical Properties of GNRs 63 4.4 Summary 66 Acknowledgements 66 References 66 5 Cutting Graphitic Materials: A Promising Way to Prepare Graphene Nanoribbons 79 Wenhua Zhang and Zhenyu Li 5.1 Introduction 79 5.2 Oxidative Cutting of Graphene Sheets 80 5.2.1 Cutting Mechanisms 80 5.2.2 Controllable Cutting 83 5.3 Unzipping Carbon Nanotubes 85 5.3.1 Unzipping Mechanisms Based on Atomic Oxygen 86 5.3.2 Unzipping Mechanisms Based on Oxygen Pairs 88 5.4 Beyond Oxidative Cutting 91 5.4.1 Metal Nanoparticle Catalyzed Cutting 92 5.4.2 Cutting by Fluorination 95 5.5 Summary 96 References 96 6 Properties of Nanographenes 101 Michael R. Philpott 6.1 Introduction 101 6.2 Synthesis 103 6.3 Computation 103 6.4 Geometry of Zigzag-Edged Hexangulenes 104 6.5 Geometry of Armchair-Edged Hexangulenes 107 6.6 Geometry of Zigzag-Edged Triangulenes 110 6.7 Magnetism of Zigzag-Edged Hexangulenes 112 6.8 Magnetism of Zigzag-Edged Triangulenes 114 6.9 Chimeric Magnetism 115 6.10 Magnetism of Oligocenes, Bisanthene-Homologs, Squares and Rectangles 117 6.10.1 Oligocene Series: C4m+2H2m+4 (na = 1; m = 2, 3, 4 . . .) 117 6.10.2 Bisanthene Series: C8m+4H2m+8 (na = 3; m = 2, 3, 4 . . .) 119 6.10.3 Square and Rectangular Nano-Graphenes: C8m+4H2m+8 (m = 2, 3, 4 . . .) 122 6.11 Concluding Remarks 122 Acknowledgment 123 References 124 7 Porous Graphene and Nanomeshes 129 Yan Jiao, Marlies Hankel, Aijun Du, and Sean C. Smith 7.1 Introduction 129 7.1.1 Graphene-Based Nanomeshes 130 7.1.2 Graphene-Like Polymers 130 7.1.3 Other Relevant Subjects 131 7.2 Transition State Theory 134 7.2.1 A Brief Introduction of the Idea 134 7.2.2 Evaluating the Partition Functions: The Well-Separated "Reactant" State 136 7.2.3 Evaluating Partition Functions: The Fully Coupled 4D TS Calculation 137 7.2.4 Evaluating Partition Functions: Harmonic Approximation for the TS Derived Directly from Density Functional Theory Calculations 138 7.3 Gas and Isotope Separation 139 7.3.1 Gas Separation and Storage by Porous Graphene 139 7.3.2 Nitrogen Functionalized Porous Graphene for Hydrogen Purification/Storage and Isotope Separation 140 7.3.3 Graphdiyne for Hydrogen Purification 144 7.4 Conclusion and Perspectives 147 Acknowledgement 147 References 147 8 Graphene-Based Architecture and Assemblies 153 Hongyan Guo, Rui Liu, Xiao Cheng Zeng, and Xiaojun Wu 8.1 Introduction 153 8.2 Fullerene Polymers 154 8.3 Carbon Nanotube Superarchitecture 156 8.4 Graphene Superarchitectures 160 8.5 C60/Carbon Nanotube/Graphene Hybrid Superarchitectures 163 8.5.1 Nanopeapods 163 8.5.2 Carbon Nanobuds 165 8.5.3 Graphene Nanobuds 168 8.5.4 Nanosieves and Nanofunnels 169 8.6 Boron-Nitride Nanotubes and Monolayer Superarchitectures 171 8.7 Conclusion 173 Acknowledgments 173 References 174 9 Doped Graphene: Theory, Synthesis, Characterization, and Applications 183 Florentino López-Ur?as, Ruitao Lv, Humberto Terrones, and Mauricio Terrones 9.1 Introduction 183 9.2 Substitutional Doping of Graphene Sheets 184 9.3 Substitutional Doping of Graphene Nanoribbons 194 9.4 Synthesis and Characterization Techniques of Doped Graphene 196 9.5 Applications of Doped Graphene Sheets and Nanoribbons 200 9.6 Future Work 201 Acknowledgments 202 References 202 10 Adsorption of Molecules on Graphene 209 O. Leenaerts B. and Partoens F. M. Peeters 10.1 Introduction 209 10.2 Physisorption versus Chemisorption 210 10.3 General Aspects of Adsorption of Molecules on Graphene 212 10.4 Various Ways of Doping Graphene with Molecules 215 10.4.1 Open-Shell Adsorbates 215 10.4.2 Inert Adsorbates 217 10.4.3 Electrochemical Surface Transfer Doping 220 10.5 Enhancing the Graphene-Molecule Interaction 221 10.5.1 Substitutional Doping 221 10.5.2 Adatoms and Adlayers 222 10.5.3 Edges and Defects 224 10.5.4 External Electric Fields 224 10.5.5 Surface Bending 225 10.6 Conclusion 226 References 226 11 Surface Functionalization of Graphene 233 Maria Peressi 11.1 Introduction 233 11.2 Functionalized Graphene: Properties and Challenges 236 11.3 Theoretical Approach 237 11.4 Interaction of Graphene with Specific Atoms and Functional Groups 238 11.4.1 Interaction with Hydrogen 238 11.4.2 Interaction with Oxygen 240 11.4.3 Interaction with Hydroxyl Groups 241 11.4.4 Interaction with Other Atoms, Molecules, and Functional Groups 245 11.5 Surface Functionalization of Graphene Nanoribbons 247 11.6 Conclusions 248 References 249 12 Mechanisms of Graphene Chemical Vapor Deposition (CVD) Growth 255 Xiuyun Zhang, Qinghong Yuan, Haibo Shu, Feng Ding 12.1 Background 255 12.1.1 Graphene and Defects in Graphene 255 12.1.2 Comparison of Methods of Graphene Synthesis 257 12.1.3 Graphene Chemical Vapor Deposition (CVD) Growth 257 12.2 The Initial Nucleation Stage of Graphene CVD Growth 261 12.2.1 C Precursors on Catalyst Surfaces 262 12.2.2 The sp C Chain on Catalyst Surfaces 262 12.2.3 The sp2 Graphene Islands 263 12.2.4 The Magic Sized sp2 Carbon Clusters 264 12.2.5 Nucleation of Graphene on Terrace versus Near Step 266 12.3 Continuous Growth of Graphene 271 12.3.1 The Upright Standing Graphene Formation on Catalyst Surfaces 271 12.3.2 Edge Reconstructions on Metal Surfaces 273 12.3.3 Growth Rate of Graphene and Shape Determination 275 12.3.4 Nonlinear Growth of Graphene on Ru and Ir Surfaces 276 12.4 Graphene Orientation Determination in CVD Growth 278 12.5 Summary and Perspectives 280 References 282 13 From Graphene to Graphene Oxide and Back 291 Xingfa Gao, Yuliang Zhao, Zhongfang Chen 13.1 Introduction 291 13.2 From Graphene to Graphene Oxide 292 13.2.1 Modeling Using Cluster Models 292 13.3 Modeling Using PBC Models 297 13.3.1 Oxidative Creation of Vacancy Defects 297 13.3.2 Oxidative Etching of Vacancy Defects 298 13.3.3 Linear Oxidative Unzipping 299 13.3.4 Linear Oxidative Cutting 300 13.4 From Graphene Oxide back to Graphene 302 13.4.1 Modeling Using Cluster Models 302 13.4.2 Modeling Using Periodic Boundary Conditions 312 13.5 Concluding Remarks 314 Acknowledgement 314 References 314 14 Electronic Transport in Graphitic Carbon Nanoribbons 319 Eduardo Costa Gir~ao, Liangbo Liang, Jonathan Owens, Eduardo Cruz-Silva, Bobby G. Sumpter, Vincent Meunier 14.1 Introduction 319 14.2 Theoretical Background 320 14.2.1 Electronic Structure 320 14.2.2 Electronic Transport at the Nanoscale 322 14.3 From Graphene to Ribbons 324 14.3.1 Graphene 324 14.3.2 Graphene Nanoribbons 325 14.4 Graphene Nanoribbon Synthesis and Processing 329 14.5 Tailoring GNR's Electronic Properties 330 14.5.1 Defect-Based Modifications of the Electronic Properties 331 14.5.2 Electronic Properties of Chemically Doped Graphene Nanoribbons 332 14.5.3 GNR Assemblies 334 14.6 Thermoelectric Properties of Graphene-Based Materials 336 14.6.1 Thermoelectricity 336 14.6.2 Thermoelectricity in Carbon 336 14.7 Conclusions 338 Acknowledgements 339 References 339 15 Graphene-Based Materials as Nanocatalysts 347 Fengyu Li and Zhongfang Chen 15.1 Introduction 347 15.2 Electrocatalysts 347 15.2.1 N-Graphene 348 15.2.2 N-Graphene-NP Nanocomposites 350 15.2.3 Non-Pt Metal on the Porphyrin-Like Subunits in Graphene 351 15.2.4 Graphyne 352 15.3 Photocatalysts 353 15.3.1 TiO2-Graphene Nanocomposite 353 15.3.2 Graphitic Carbon Nitrides (g-C3N4) 355 15.4 CO Oxidation 356 15.4.1 Metal-Embedded Graphene 357 15.4.2 Metal-Graphene Oxide 358 15.4.3 Metal-Graphene under Mechanical Strain 359 15.4.4 Metal-Embedded Graphene under an External Electric Field 360 15.4.5 Porphyrin-Like Fe/N/C Nanomaterials 361 15.4.6 Si-Embedded Graphene 361 15.4.7 Experimental Aspects 361 15.5 Others 362 15.5.1 Propene Epoxidation 362 15.5.2 Nitromethane Combustion 362 15.6 Conclusion 363 Acknowledgements 364 References 364 16 Hydrogen Storage in Graphene 371 Yafei Li and Zhongfang Chen 16.1 Introduction 371 16.2 Hydrogen Storage in Molecule Form 373 16.2.1 Hydrogen Storage in Graphene Sheets 373 16.2.2 Hydrogen Storage in Metal Decorated Graphene 374 16.2.3 Hydrogen Storage in Graphene Networks 377 16.2.4 Notes to Computational Methods 381 16.3 Hydrogen Storage in Atomic Form 382 16.3.1 Graphane 382 16.3.2 Chemical Storage of Hydrogen by Spillover 383 16.4 Conclusion 386 Acknowledgements 386 References 386 17 Linking Theory to Reactivity and Properties of Nanographenes 393 Qun Ye, Zhe Sun, Chunyan Chi, and Jishan Wu 17.1 Introduction 393 17.2 Nanographenes with Only Armchair Edges 394 17.3 Nanographenes with Both Armchair and Zigzag Edges 397 17.3.1 Structure of Rylenes 398 17.3.2 Chemistry at the Armchair Edges of Rylenes 398 17.3.3 Anthenes and Periacenes 402 17.4 Nanographene with Only Zigzag Edges 405 17.4.1 Phenalenyl-Based Open-Shell Systems 406 17.5 Quinoidal Nanographenes 411 17.5.1 Bis(Phenalenyls) 412 17.5.2 Zethrenes 414 17.5.3 Indenofluorenes 417 17.6 Conclusion 417 References 418 18 Graphene Moir´e Supported Metal Clusters for Model Catalysis Studies 425 Bradley F. Habenicht, Ye Xu, and Li Liu 18.1 Introduction 425 18.2 Graphene Moir´e on Ru(0001) 426 18.3 Metal Cluster Formation on g/Ru(0001) 430 18.4 Two-dimensional Au Islands on g/Ru(0001) and its Catalytic Activity 434 18.5 Summary 440 Acknowledgments 441 References 441 Index