Search results for "Graphene oxide paper"

Bottom-up realization and electrical characterization of a graphene-based device.

2016

We propose a bottom-up procedure to fabricate an easy-to-engineer graphene-based device, consisting of a microstrip-like circuit where few-layer graphene nanoplatelets are used to contact two copper electrodes. The graphene nanoplatelets are obtained by the microwave irradiation of intercalated graphite, i.e., an environmentally friendly, fast and low-cost procedure. The contact is created by a bottom-up process, driven by the application of a DC electrical field in the gap between the electrodes, yielding the formation of a graphene carpet. The electrical resistance of the device has been measured as a function of the gap length and device temperature. The possible use of this device as a …

Graphene electrochemical responses sense surroundings

2012

Abstract Graphite oxide (GO) paper, obtained by direct filtration of exfoliated GO in water over PTFE membrane filters, was reduced by using hydrazine vapours. The graphene-paper thus obtained was characterized by the combination of different techniques. The electrochemical characterization by cyclic voltammetry, chronoamperometry and chronopotentiometry presents a strong influence of the working conditions: temperature, electrolyte concentration and current on the electrochemical responses, indicating a good ability of the material to sense ambient and working conditions. Electrochemical devices based on graphene are expected to work as dual, and simultaneous, sensing-actuators.

Electrophoretic Nanocrystalline Graphene Film Electrode for Lithium Ion Battery

2015

Graphene sheets were fabricated by electrophoretic deposition method from water suspension of graphene oxide followed by thermal reduction. The formation of nanocrystalline graphene sheets has been confirmed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The electrochemical performance of graphene sheets as anode material for lithium ion batteries was evaluated by cycling voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. Fabricated graphene sheets exhibited high discharge capacity of about 1120 mAhg−1 and demonstrated good reversibility of lithium intercalation and deintercalation in graphene sheet film with capacity…

Technical Program

2015

The synthesis of a hybrid graphene–nickel/manganese mixed oxide and its performance in lithium-ion batteries

2012

Abstract Mixing of aqueous suspensions of delaminated NiMn layered double hydroxide (LDH) and graphene oxide leads to the instantaneous precipitation of a hybrid material that after calcination under inert atmosphere at 450 °C leads to Ni6MnO8 nanoparticles deposited on larger reconstituted graphene sheets. This material exhibits electrical conductivity similar to graphite, superparamagnetism and can be used as an anode for Li-ion batteries. A maximum capacity value of 1030 mA h g−1 was found during the first discharge, and capacity values higher than 400 mA h g−1 were still achieved after 10 cycles. The methodology used here should allow the preparation of a large variety of hybrid graphen…

Synthesis of graphene oxide-intercalated α-hydroxides by metathesis and their decomposition to graphene/metal oxide composites

2010

Graphene oxide-intercalated alpha-metal hydroxides were prepared using layers from the delaminated colloidal dispersions of cetyltrimethylammonium-intercalated graphene oxide and dodecylsulfate-intercalated alpha-hydroxide of nickel/cobalt as precursors. The reaction of the two dispersions leads to de-intercalation of the interlayer ions from both the layered solids and the intercalation of the negatively charged graphene oxide sheets between the positively charged layers of the alpha-hydroxide. Thermal decomposition of the intercalated solids yields graphene/nanocrystalline metal oxide composites. Electron microscopy analysis of the composites indicates that the nanoparticles are intercala…

Controllable coverage of chemically modified graphene sheets with gold nanoparticles by thermal treatment of graphite oxide with N,N-dimethylformamide

2013

Abstract We describe a simple chemical method to reduce and functionalize graphite oxide by reaction with dimethylformamide under controlled heating. Our experiments suggest that the reaction conditions assist the decomposition of the solvent to produce dimethylamine molecules that can react with the oxygen-rich functional groups covering the surface of the exfoliated layers of graphene, therefore generating chemically modified graphene (CMG). These N-functionalities have been next used as anchoring points for the grafting of Au nanoparticles. Given that the functionalization extent can be controlled with the temperature and reaction time, our approach can be considered as a straightforward…

Multifunctional properties of nanocomposites made by 1D and 2D graphene based fillers

2015

High aspect ratio graphene based fillers with different dimensionalities showed the ability to greatly modify rheological, mechanical, thermal and electrical properties of polymers at very low content. In this work, the effect of filler dimensionality on the multifunctional properties of an epoxy matrix reinforced by both carbon nanotubes (1D) and graphite nanoplatelets (2D) have been investigated across the percolation region. Keywords-- Carbon nanotube, Graphite nanoplatelet, nanocomposites, mechanical properties, ...

Graphene as a carbon source effects the nanometallurgy of nickel in Ni,Mn layered double hydroxide-graphene oxide composites.

2012

[EN] Thermal treatment of the hybrid material formed by the spontaneous precipitation of graphene oxide and Ni,Mn layered double hydroxide leads to the segregation of nickel metal nanoparticles (Ni NPs) and the decomposition of graphene to CO2. Increasing the temperature increases the Ni NP size and results in the complete disappearance of graphene.

Dimensional Confinement in Carbon-based Structures - From 3D to 1D

2017

We present an overview of charge transport in selected one-, two- and three-dimensional carbon-based materials with exciting properties. The systems are atomically defined bottom-up synthesized graphene nanoribbons, doped graphene and turbostratic graphene micro-disks, where up to 100 graphene layers are rotationally stacked. For turbostratic graphene we show how this system lends itself to spintronic applications. This follows from the inner graphene layers where charge carriers are protected and thus highly mobile. Doped graphene and graphene nanoribbons offer the possibility to tailor the electronic properties of graphene either by introducing heteroatoms or by confining the system geome…