Chemically derived graphene oxide (GO) possesses a unique set of properties arising from oxygen functional groups that are introduced during chemical exfoliation of graphite. Large‐area thin‐film ...deposition of GO, enabled by its solubility in a variety of solvents, offers a route towards GO‐based thin‐film electronics and optoelectronics. The electrical and optical properties of GO are strongly dependent on its chemical and atomic structure and are tunable over a wide range via chemical engineering. In this Review, the fundamental structure and properties of GO‐based thin films are discussed in relation to their potential applications in electronics and optoelectronics.
For over 150 years, oxidation of graphite has been known to result in water‐soluble graphite oxide. However, it has been only recently recognized that graphite oxide splits into atomically thin graphene oxide (GO) upon dissolution. GO can be produced on a large scale, handled in solution, assembled into thin films, and deposited on arbitrary substrates. This Review introduces fundamental properties of GO and summarizes recent achievements in device applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Efficient intercalation of ions in layered materials forms the basis of electrochemical energy storage devices such as batteries and capacitors. Recent research has focused on the exfoliation of ...layered materials and then restacking the two-dimensional exfoliated nanosheets to form electrodes with enhanced electrochemical response. Here, we show that chemically exfoliated nanosheets of MoS2 containing a high concentration of the metallic 1T phase can electrochemically intercalate ions such as H(+), Li(+), Na(+) and K(+) with extraordinary efficiency and achieve capacitance values ranging from ∼400 to ∼700 F cm(-3) in a variety of aqueous electrolytes. We also demonstrate that this material is suitable for high-voltage (3.5 V) operation in non-aqueous organic electrolytes, showing prime volumetric energy and power density values, coulombic efficiencies in excess of 95%, and stability over 5,000 cycles. As we show by X-ray diffraction analysis, these favourable electrochemical properties of 1T MoS2 layers are mainly a result of their hydrophilicity and high electrical conductivity, as well as the ability of the exfoliated layers to dynamically expand and intercalate the various ions.
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IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UL, UM, UPUK
Two‐dimensional (2D) transition‐metal dichalcogenide (TMD) nanosheets have emerged as a fascinating new class of materials for catalysis. These nanosheets are active for several important catalysis ...reactions including hydrogen evolution from water. The rich chemistry of TMDs combined with numerous strategies that allow tuning of their electronic properties make these materials very attractive for understanding the fundamental principles of electro‐ and photocatalysis, as well as for developing highly efficient, renewable, and affordable catalysts for large‐scale production of hydrogen. Recent developments are highlighted and important challenges in using TMDs as catalysts are also discussed.
Transition metal dichalcogenide (TMD) nanosheets are promising catalysts for evolution of hydrogen. TMDs possess a wide range of electronic and catalytic properties so that important fundamental parameters related to catalysis can be investigated. Recent progress on the study of 2D TMD nanosheets for enhancing their electro‐ and photocatalytic activity is discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Transition metal dichalcogenides (TMDs) represent a family of materials with versatile electronic, optical, and chemical properties. Most TMD bulk crystals are van der Waals solids with strong ...bonding within the plane but weak interlayer bonding. The individual layers can be readily isolated. Single layer TMDs possess intriguing properties that are ideal for both fundamental and technologically relevant research studies. We review the structure and phases of single and few layered TMDs. We also describe recent progress in phase engineering in TMDs. The ability to tune the chemistry by choosing a unique combination of transition metals and chalcogen atoms along with controlling their properties by phase engineering allows new functionalities to be realized with TMDs.
The co-existence of 2H, 1T and 1T′ phases in monolayered TMDs.
Guest editors Manish Chhowalla, Zhongfan Liu and Hua Zhang introduce the Two-dimensional Transition Metal Dichalcogenide (TMD) Nanosheets issue of
Chemical Society Reviews
Guest editors Hua Zhang, Manish Chhowalla and Zhongfan Liu introduce the 2D nanomaterials: graphene and transition metal dichalcogenides themed issue of
Chemical Society Reviews
.
Low-dimensional materials and their hybrids have emerged as promising candidates for electrocatalytic and photocatalytic hydrogen evolution and CO2 conversion into useful molecules. Progress in ...synthetic methods for the production of catalysts coupled with a better understanding of the fundamental catalytic mechanisms has enabled the rational design of catalytic nanomaterials with improved performance and selectivity. In this Review, we analyse the state of the art in the implementation of low-dimensional nanomaterials and their van der Waals heterostructures for hydrogen evolution and CO2 reduction by electrocatalysis and photocatalysis. We explore the mechanisms involved in both reactions and the different strategies to further optimize the activity, efficiency and selectivity of low-dimensional catalysts.The electrochemical oxidation and reduction of water and carbon dioxide are associated with the release or storage of energy. This Review reports the latest developments in the design and use of low-dimensional materials and their van der Waals heterostructures for electrocatalytic and photocatalytic hydrogen evolution and CO2 conversion.
The electrical properties of solution-processed composite thin films consisting of functionalized graphene sheets (FGS) as the filler and polystyrene (PS) as the host material are described. We ...demonstrate that transistors from graphene-based composite thin films exhibit ambipolar field effect characteristics, suggesting transport via percolation among FGS in the insulating PS matrix. Device characteristics as a function of the FGS size are also reported. The results indicate that devices fabricated using the largest size FGS yield the highest mobility values. This simple and scaleable fabrication scheme based on a commodity plastic could be useful for low-cost, macro-scale electronics.
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IJS, KILJ, NUK, PNG, UL, UM
Graphene oxide (GO) can be considered as one of the most visible outcomes of graphene research in terms of large scale production and commercialization prospects. Although GO can be easily prepared ...by oxidation-exfoliation of graphite in agitated solutions, the size of these sheets is generally limited due to fragmentation along fault lines during chemical oxidation and exfoliation in agitated solutions. In this account, we discuss recent strategies which have been developed for the preparation of large sized graphene oxide (LGO) sheets with lateral sizes >10 μm, using chemically expanded graphite as the starting material. LGO has a much lower density of defects than GO prepared using the conventional Hummers' method and can be readily transformed into graphene by chemical reduction. In addition, the unique advantages of using LGO sheets as a performance enhancer are discussed. Finally, this review also discusses recent advances in the chemical and electrochemical reduction of graphene oxide.
Graphene oxide (GO) can be considered as one of the most visible outcomes of graphene research in terms of large scale production and commercialization prospects.
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