Ray Applications of Graphene and Graphene-Oxide based Nanomaterials

1. Auflage 2015
ISBN: 978-0-323-37522-1
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 92 Seiten

Reihe: Micro and Nano Technologies

Carbon nanomaterials have a unique place in Nanoscience owing to their exceptional electrical, thermal, chemical and mechanical properties and have found application in areas as diverse as composite materials, energy storage and conversion, sensors, drug delivery, field emission devices and nano-scale electronic components. Conjugated carbon nanomaterial covers the areas of carbon nanotubes, fullerenes and graphene. Graphene is the newest of the carbon nanomaterials and promises to be a very active field. Already since its isolation in 2004 it has grabbed the attention of the chemistry, materials and physics communities. It promises to rival carbon nanotubes in terms of properties and potential applications with the number of publications rising from ca. 130 in 2005 to ca. 2,800 in 2010. In this short book Sekhar Ray gives an overview on graphene and graphene-oxide with a strong focus on applications. Structured in three chapters, one on graphene, one on graphene-oxide and one on graphene based nanoparticles his resource describes in each chapter the preparation (including synthesis and functionalization) and material properties before detailing a whole range of applications. Ray finishes each chapter with information on remaining challenges and perspectives. - Written by an expert in the field who, during his last 17 years of research, has published more than 80 peer reviewed articles in recognized international journals - Gives full-chapter overviews on Graphene, Graphene-Oxide, and Graphene based nanoparticles - Focusses on applications

Autoren/Hrsg.

Ray, Sekhar

Inhaltsverzeichnis

1;Front Cover;1
2;Applications of Graphene and Graphene-Oxide Based Nanomaterials;4
3;Copyright Page;5
4;Contents;6
5;Acknowledgments;8
6;1 Application and Uses of Graphene;10
6.1;1.1 Introduction;10
6.2;1.2 Preparation/Synthesis of Graphene;11
6.3;1.3 Properties of Graphene;12
6.4;1.4 Potential Application and Uses of Graphene;13
6.4.1;1.4.1 Graphene in Hydrogen Storage Devices;13
6.4.2;1.4.2 Graphene as a Battery;18
6.4.3;1.4.3 Application of Graphene Thin Film as Transparent Conductor (Electrodes);20
6.4.3.1;1.4.3.1 Graphene as Transparent Conducting Electrodes;21
6.4.3.2;1.4.3.2 Flexible Electronics;21
6.4.3.3;1.4.3.3 Touch Screen;21
6.4.4;1.4.4 Solar Cells and OVPs;22
6.4.4.1;1.4.4.1 Organic Photovoltaic Cells;23
6.4.5;1.4.5 Fuel Cells;24
6.4.6;1.4.6 Microbial Biofuel Cells;25
6.4.7;1.4.7 Enzymatic Biofuel Cells;25
6.4.8;1.4.8 Organic Light-Emitting Diodes;25
6.4.9;1.4.9 Graphene as a Super-Capacitor/Ultra-Capacitors;26
6.4.10;1.4.10 Spintronics;28
6.4.10.1;1.4.10.1 Many Challenges and Opportunities Await for Spin and Magnetism in Graphene;29
6.4.11;1.4.11 Integrated Circuits;30
6.4.12;1.4.12 Transistors;30
6.4.13;1.4.13 Ballistic Transistors;32
6.4.14;1.4.14 Radio Frequency Applications;32
6.4.14.1;1.4.14.1 Nano Antennas;32
6.4.15;1.4.15 Sound Transducer;33
6.4.16;1.4.16 Graphene as Sensor;33
6.4.16.1;1.4.16.1 Electrochemical Sensor;34
6.4.16.2;1.4.16.2 Gas Sensors;34
6.4.16.3;1.4.16.3 Biosensors;34
6.4.17;1.4.17 Composite Materials;35
6.4.18;1.4.18 Liquid Crystal Displays;36
6.4.19;1.4.19 Graphene Quantum Dots;36
6.4.20;1.4.20 Frequency Multiplier;37
6.4.21;1.4.21 Optical Modulator;37
6.4.22;1.4.22 Infrared Light Detection;37
6.4.23;1.4.23 Graphene Photodetectors;37
6.4.24;1.4.24 Piezoelectricity;38
6.4.25;1.4.25 Graphene as Purification of Water;38
6.5;1.5 Conclusion and Perspectives of Graphene;38
6.6;1.6 The Present Challenges and Future Research in Graphene Nanomaterials;39
6.7;References;40
7;2 Application and Uses of Graphene Oxide and Reduced Graphene Oxide;48
7.1;2.1 Introduction;48
7.2;2.2 Preparation/Synthesis of GO/rGO;50
7.3;2.3 Surface Functionalization of GO and rGO;52
7.4;2.4 Properties of GO and rGO;53
7.5;2.5 Applications of GO and rGO;54
7.5.1;2.5.1 GO/rGO in Electronics Devices;54
7.5.2;2.5.2 GO/rGO as Energy Storage Device;55
7.5.3;2.5.3 GO/rGO as Biosensors;55
7.5.4;2.5.4 GO/rGO as Biomedical Applications;58
7.5.5;2.5.5 GO as Water Purification (Filter);58
7.5.6;2.5.6 GO/rGO as Coating Technology;59
7.5.7;2.5.7 GO/rGO Composites and Paper-Like Materials;59
7.6;2.6 Conclusion and Perspectives of GO/rGO;60
7.7;2.7 The Present Challenges and Future Research in GO/rGO Nanomaterial;61
7.8;References;62
8;3 Graphene-Based Carbon Nanoparticles for Bioimaging Applications;66
8.1;3.1 Introduction;66
8.2;3.2 Preparation Process of Carbon Nanoparticles;68
8.2.1;3.2.1 Synthesis of CP from Oxidation of Burning Candle Soot;68
8.2.2;3.2.2 Synthesis of Carbon Nanoparticle from Carbohydrate Carbonization Method;68
8.2.3;3.2.3 Functionalization of FCN;69
8.3;3.3 Properties of Carbon Nanoparticles;71
8.3.1;3.3.1 Physical and Structural Properties;71
8.3.2;3.3.2 Chemical and Bonding Properties;76
8.3.3;3.3.3 Optical-Luminescence Properties;79
8.4;3.4 Application of Carbon Nanoparticles in Bioimaging Process;82
8.5;3.5 Cytotoxicity of FCN;84
8.6;3.6 Discussion;86
8.7;3.7 Conclusion and Perspectives of Carbon Nanoparticles;88
8.8;3.8 Present Challenges and Future Research in Carbon Nanoparticles;89
8.9;References;89

Leseproben

Chapter 2 Application and Uses of Graphene Oxide and Reduced Graphene Oxide
Sekhar C. Ray,    Department of Physics, College of Science, Engineering and Technology, University of South Africa, Florida Park, Johannesburg, South Africa Graphene oxide (GO) is a unique material that can be viewed as a single monomolecular layer of graphite with various oxygen-containing functionalities such as epoxide, carbonyl, carboxyl, and hydroxyl groups. When the GO is reduced with a suitable process, the reduced graphene oxide (rGO) formed resembles graphene but contains residual oxygen and other heteroatoms, as well as structural defects. GO and rGO have been used in nanocomposite materials, polymer composite materials, energy storage, biomedical applications, and catalysis, and as a surfactant with some overlaps between these fields. In this chapter, their different uses and applications are described. Keywords
Graphene oxide (GO); reduced graphene oxide (rGO); synthesis of GO/rGO; properties of GO/rGO; applications of GO/rGO 2.1 Introduction
Graphite oxide has a layered structure similar to that of graphite, but the plane of carbon atoms in graphite oxide is heavily decorated by oxygen-containing groups, which not only expand the interlayer distance but also make the atomic-thick layers hydrophilic. These oxidized layers could exfoliate in water under ultrasonication. If the exfoliated sheets contain only one or a few layers of carbon atoms like graphene, then these sheets are named graphene oxide (GO) (Novoselov et al., 2004). So, GO is a single-atomic-layered material comprising carbon, hydrogen, and oxygen molecules by the oxidation of graphite crystals, as shown in Figure 2.1 (Stergiou et al., 2014), which are inexpensive and abundant. It is dispersible in water and easy to process. Most importantly, the GO can be (partly) reduced to graphene-like sheets by removing the oxygen-containing groups and with the recovery of a conjugated structure. The reduced GO (rGO) sheets are usually considered one kind of chemically derived graphene and are known as rGO. Some other names have also been given to rGO, such as functionalized graphene, chemically modified graphene, chemically converted graphene, or reduced graphene (Eda et al., 2010). GO has two important characteristics: (i) it can be produced using inexpensive graphite as the raw material and by using cost-effective chemical methods with a high yield and (ii) it is highly hydrophilic and can form stable aqueous colloids to facilitate the assembly of macroscopic structures by simple and cheap solution processes. The graphene sheet consists of only trigonally bonded sp2 carbon atoms and is perfectly flat (Lui et al., 2009), apart from its microscopic ripples. The heavily decorated GO sheets consist partly of tetrahedrally bonded sp3 carbon atoms, which are displaced slightly above or below the graphene plane (Schniepp et al., 2006). Because of the structure deformation and the presence of covalently bonded functional groups, GO sheets are atomically rough (Paredes et al., 2009; Mkhoyan et al., 2009). Several researchers (Paredes et al., 2009; Kudin et al., 2007; Gomez-Navarro et al., 2007, 2010) have studied the surface of GO and observed highly defective regions, probably due to the presence of oxygen, and other areas are nearly intact. A report shows that the graphene-like honeycomb lattice in GO is preserved, albeit with disorder (i.e., the carbon atoms attached to functional groups are slightly displaced), but the overall size of the unit cell in GO remains similar to that of graphene (Pandey et al., 2008). Hence, GO can be described as a random distribution of oxidized areas with oxygen-containing functional groups combined with nonoxidized regions where most of the carbon atoms preserve sp2 hybridization. GO and rGO are hot topics in the research and development of graphene, especially regarding mass applications of graphene.
Figure 2.1 General chemical modification routes for exfoliated graphene sheets. (a) [3+2] 1,3-dipolar cycloaddition of in situ-generated azomethine ylides, (b) [1+2] Bingel cycloaddition, (c) aryl diazonium addition, and (d) azide addition. Reprinted with permission from Stergiou et al., 2014. 2.2 Preparation/Synthesis of GO/rGO
Graphite is a three-dimensional (3D) carbon-based material comprising millions of graphene layers, whereas graphite oxide is a little different. By oxidation of graphite with strong oxidizing agents, oxygenated functionalities are introduced in the graphite structure, which not only expand the layer separation but also make the material hydrophilic (meaning that they can be dispersed in water). This property enables the graphite oxide to be exfoliated in water using sonication, ultimately producing single-layer graphene or graphene with a few layers, known as GO. Many modern procedures for the synthesis of GO are based on the method first reported by Hummers in which graphite is oxidized by a solution of potassium permanganate in sulfuric acid (Hummers et al., 1958; Kim et al., 2010). Hydrazine is generally used for the reduction of GO (Gilje et al., 2007). However, hydrazine is highly toxic and can potentially functionalize GO with nitrogen heteroatoms (Shin et al., 2009); because of these issues, alternatives to hydrazine including NaBH4 (Lightcap et al., 2013), ascorbic acid (Fernández-Merino et al., 2010), and HI (Moon et al., 2010; Pei et al., 2010), among others, have been used for the reduction of GO. GO can be reduced to a thin film or in an aqueous solution. GO is effectively a by-product of this oxidization because when the oxidizing agents react with graphite, the interplanar spacing between the layers of graphite is increased. The completely oxidized compound can then be dispersed in a base solution such as water, and GO is then produced. Graphite oxide and GO are very similar chemically, but structurally they are very different. The main difference between graphite oxide and GO is the interplanar spacing between the individual atomic layers of the compounds, which is caused by water intercalation. This increased spacing, caused by the oxidization process, also disrupts the sp2 bonding network, meaning that both graphite oxide and GO are often described as electrical insulators. GO is a poor conductor but its treatment with light, heat, or chemical reduction can restore most properties of the famed pristine graphene. To turn graphite oxide into GO, a few methods are possible. The most common techniques are by using sonication, stirring, or a combination of the two. Sonication can be a very time-efficient way of exfoliating graphite oxide, and it is extremely successful at exfoliating graphene; however, it can also heavily damage the graphene flakes, reducing them in surface size from microns to nanometers, and it also produces a wide variety of graphene platelet sizes. The main difference between graphite oxide and GO is the number of layers. Although graphite oxide is a multilayer system in GO dispersion, a few layers of flakes and a monolayer of flakes can be found. Reducing GO to produce rGO is an extremely vital process because it has a large impact on the quality of the rGO produced; therefore, it will determine how close rGO will come in terms of structure to pristine graphene (Chuang et al., 2014). In large-scale operations where scientific engineers need to utilize large quantities of graphene for industrial applications such as energy storage, rGO is the most obvious solution because of the relative ease in creating sufficient quantities of graphene with desired quality levels. There are a number of ways reduction can be achieved, although they are all methods based on chemical, thermal, or electrochemical means. Some of these techniques are able to produce very high-quality rGO, similar to pristine graphene, but they can be complex or time-consuming to perform. In the past, scientists have created rGO from GO by: • Treating GO with hydrazine hydrate and maintaining the solution at 100 for 24 h • Exposing GO to hydrogen plasma for a few seconds • Exposing GO to another form of strong pulse light, such as that produced by xenon flashtubes • Heating GO in distilled water at varying degrees for different lengths of time • Combining GO with an expansion–reduction agent such as urea and then heating the solution to cause the urea to release reducing gases, followed by cooling • Directly heating GO to very high levels in a furnace • Linear sweep voltammetry Reducing GO by using chemical reduction is a very scalable method; unfortunately, the rGO produced has often resulted in relatively poor yields in terms of surface area and electronic conductibility. Thermally reducing GO at temperatures of 1000°C or more creates rGO that has been shown to have a very high surface area, close to that of pristine graphene. The heating process damages the structure of the graphene platelets as pressure builds and carbon dioxide is released. This also causes a substantial reduction in the mass of the GO, creating imperfections and vacancies, and potentially also has an effect on the mechanical strength of the rGO produced. Electrochemical reduction of GO is a method that has been shown to produce very high-quality rGO, almost identical in terms of structure to pristine graphene. This...