Utilization of multiple graphene layers in fuel cells. 1. An improved technique for the exfoliation of graphene-based nanosheets from graphite

Saner, Burcu; Okyay, Firuze; Yürüm, Yuda

doi:10.1016/j.fuel.2010.03.036

Cited by 90 publications

(59 citation statements)

References 18 publications

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“…Graphene nanosheets were produced by a safer and mild chemical route consists of oxidation, ultrasonic treatment and chemical reduction in large quantities (7). At first, potassium dichromate (10.5 g), sulfuric acid (150 mL) and 7.5 mL distilled water were mixed in ice-bath to prepare chromic acid as an oxidizing agent.…”

Section: Separation Of Graphene Nanosheetsmentioning

confidence: 99%

“…This result indicated that PPy had an amorphous structure. Graphite flakes were partially oxidized in the adjusted synthesis conditions using concentrated sulfuric acid, potassium dichromate, and acetic anhydride (7). XRD pattern of GO sheets showed low intensity of 002 diffraction peak at 2ϴ=26.5 o , Figure 4b.…”

Section: X-ray Diffraction Analysismentioning

confidence: 99%

“…XRD pattern of GO sheets showed low intensity of 002 diffraction peak at 2ϴ=26.5 o , Figure 4b. Longer oxidation time led to decrease in the intensity of 002 peak, enhanced the interlayer spacing between graphene sheets and switched the carbon backbone from sp 2 to sp 3 structure (7,17). After covering of GO sheets by PPy with different feeding ratios, 002 peak intensity decreased and the peak was broadened.…”

Section: X-ray Diffraction Analysismentioning

confidence: 99%

“…Graphene nanosheets are electron acceptors while the conducting polymer serves as an electron donor (14). In this study, graphene nanosheets were fabricated in large quantities by adopting a safer and mild chemical route including oxidation, ultrasonic treatment and chemical reduction (7). PPy was coated on GO sheets and graphene nanosheets by in situ polymerization with different pyrrole (Py) feed ratios.…”

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Layer-by-Layer Polypyrrole Coated Graphite Oxide and Graphene Nanosheets as Catalyst Support Materials for Fuel Cells

Saner

Gürsel

Yürüm

2012

Fullerenes, Nanotubes and Carbon Nanostructures

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 applications yet it is necessary to develop low cost and more efficient PEMFCs. The heart of the PEMFC is the membrane electrode assembly composed of a proton exchange membrane sandwiched between two porous gas diffusion electrodes. These electrodes are made up of a catalyst support material or gas diffusion layer and a catalyst layer. Catalyst support materials have significant effect on the cost, performance and the durability of PEMFCs. The ideal support materials should provide high dispersion, utilization, activity, and stability for the catalyst especially platinum (Pt) (1-3). Carbon black has been extensively used as a catalyst support for Pt in PEMFC. However, alternatives to carbon black are still needed to enhance catalyst utilization and reduce the cost.Novel nanostructured carbon materials (carbon nanofibers, carbon nanotubes and graphene) have generated intense interest as catalyst supports in PEMFCs due to their unique structures and properties (4, 5). However, the main drawbacks of these materials are high production cost and mass production. At this point, graphene nanosheets can serve as the promising catalyst support because of its low-cost and large-scale production. In addition, free standing graphene sheets have large surface area, high thermal and electrical conductivity, and high mobility of charge carriers (6). According to Saner et al. (7) a few graphene layers provide effective surface area to improve metal-support interaction. Authors proposed a mild chemical exfoliation method for the reduction of layer number in graphitic structure and the production in large quantities of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Ruoff et al. (9) showed that chemically modified graphene was incorporated into ultracapacitor test electrodes in order to increase the energy density of the packaged ultracapacitor by increasing the electrode thickness and eliminating additives.Conducting polymers have high conductivity, are lightweight, inexpensive, flexible, airstable, and environmentally friendly but the major obstacle of conducting polymers as an electrode material is the degradation during cycling because of the volume change of the polymer due to the insertion/deinsertion of counter ions (10).Therefore, nanocomposites based on conducting polymers and carbon nanomaterials can be used as a potential catalyst support to improve the properties of supports and extend life cycle of fuel cells. There have been several attempts for the synthesis of these type of nanocomposites. Previously, Wang et al. (11) reported that the remarkable electrical conductivity and specific capacitance of graphene/polya...

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Section: Separation Of Graphene Nanosheetsmentioning

confidence: 99%

Section: X-ray Diffraction Analysismentioning

confidence: 99%

Section: X-ray Diffraction Analysismentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Layer-by-Layer Polypyrrole Coated Graphite Oxide and Graphene Nanosheets as Catalyst Support Materials for Fuel Cells

Saner

Gürsel

Yürüm

2012

Fullerenes, Nanotubes and Carbon Nanostructures

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“…As a 2D structured carbon material, graphene has a large surface area and both sides of the sheets can used to support catalyst. Furthermore, due to its mechanical, structural, and electronic properties, graphene exhibits an outstanding performance as the support material for fuel cells since its discovery [59][60][61].…”

Section: Fuel Cellsmentioning

confidence: 99%

Graphene-based hybrid materials and their applications in energy storage and conversion

2012

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Graphene attracts more and more scientists and researchers owing to its superior electronic, thermal, and mechanical properties. For material scientists, graphene is a kind of versatile building blocks, and considerable progress has been made in recent years. Graphene-based hybrid materials have been prepared by incorporating inorganic species and/or cross-linking of organic species through covalent and/or noncovalent interactions. The graphene-based hybrid materials show improved or excellent performance in various fields. In this review, we summarize the synthesis of graphene and graphene-based hybrid materials, and their applications in energy storage and conversion. graphene, hybrid material, energy storage, energy conversion Citation:Zhou D, Cui Y, Han B H. Graphene-based hybrid materials and their applications in energy storage and conversion.

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Three‐Dimensional Graphene‐Based Structures: Production Methods, Properties, and Applications

Poudeh

Yıldız

Menceloǵlu

et al. 2019

Handbook of Graphene

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Graphene, a two-dimensional (2D) sp 2-hybridized carbon sheet, shows excellent chemical, mechanical, and physical properties owing to its unique structure, which makes it a great potential in the energy storage devices, sensors, composite materials, and biotechnology. The utilization of graphene sheets into the macroscopic structures is one of the important issues since 2D graphene sheets tend to restack together in bulk materials due to strong π-π interactions and van der Waals forces. The aggregation of graphene sheets and their crumbling lead to a significant decrease in electrical conductivity, surface area, and mechanical strength which negatively affects the utilization of graphene in the practical applications. Recently, three-dimensional (3D) graphene materials have been attracting much attention since they not only preserve the intrinsic properties of 2D graphene sheets by inhibiting the agglomeration behavior of 2D graphene sheets but also provide advanced functions with improved performance in various applications. The content of this chapter covers (i) a brief summary of production techniques of 2D graphene and its drawbacks, (ii) main strategies for the development of 3D graphene structures, (iii) production methods, and (iv) possible applications of 3D graphene architectures in composites and energystorage devices.

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Utilization of multiple graphene layers in fuel cells. 1. An improved technique for the exfoliation of graphene-based nanosheets from graphite

Cited by 90 publications

References 18 publications

Layer-by-Layer Polypyrrole Coated Graphite Oxide and Graphene Nanosheets as Catalyst Support Materials for Fuel Cells

Layer-by-Layer Polypyrrole Coated Graphite Oxide and Graphene Nanosheets as Catalyst Support Materials for Fuel Cells

Graphene-based hybrid materials and their applications in energy storage and conversion

Three‐Dimensional Graphene‐Based Structures: Production Methods, Properties, and Applications

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