Dr De-en Jiang, Chemical Sciences Division, Oak Ridge National Laboratory, USA
Dr 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 Juan
Dr 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.

What are the chemical aspects of graphene as a novel 2D material and how do they relate to the molecular structure? This book addresses these important questions from a theoretical and computational standpoint.
Graphene Chemistry: Theoretical Perspectives presents recent exciting developments to correlate graphene's properties and functions to its structure through state-of-the-art computational studies. This book focuses on the chemistry aspect of the structure-property relationship for many fascinating derivatives of graphene; various properties such as electronic structure, magnetism, and chemical reactivity, as well as potential applications in energy storage, catalysis, and nanoelectronics are covered. The book also includes two chapters with significant experimental portions, demonstrating how deep insights can be obtained by joint experimental and theoretical efforts.
Topics covered include:
* Graphene ribbons: Edges, magnetism, preparation from unzipping, and electronic transport
* Nanographenes: Properties, reactivity, and synthesis
* Clar sextet rule in nanographene and graphene nanoribbons
* Porous graphene, nanomeshes, and graphene-based architecture and assemblies
* Doped graphene: Theory, synthesis, characterization and applications
* Mechanisms of graphene growth in chemical vapor deposition
* Surface adsorption and functionalization of graphene
* Conversion between graphene and graphene oxide
* Applications in gas separation, hydrogen storage, and catalysis
Graphene Chemistry: Theoretical Perspectives provides a useful overview for computational and theoretical chemists who are active in this field and those who have not studied graphene before. It is also a valuable resource for experimentalist scientists working on graphene and related materials, who will benefit from many concepts and properties discussed here.

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