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.

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.

List of Contributors xv

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 Oxyge…