The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In order to improve the stability and decrease the cytotoxicity of silver nanoparticle (AgNP), a polyethyleneimine-modified reduced graphene oxide (PEI-rGO) was used as the substrate of AgNPs, and a PEI-rGO–AgNP hybrid was prepared by anchoring the AgNPs on the reduced graphene oxide surface. Such a hybrid showed substantially higher antibacterial activity than polyvinyl pyrrolidone (PVP)-stabilized...
We analyze the local microscopic deformation left by Au, Ag and Cu islands on carbon nanotube walls observed by transmission electron microscopy. We employ finite-element simulations within continuum elasticity theory to demonstrate that the observed deformation of the tube walls is the result of elastic strain energy relaxation induced by the nucleation of noble metal clusters on the graphene lattice...
In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (E g ) and infrared (E u ) phonon modes, due to different doping in the two layers. We theoretically...
A carbon block with ultra-high anisotropy was produced from a commercial graphite paper as the thermal reinforcement and a thermosetting phenolic resin as the binder. Hot-pressing at a maximum temperature of 200°C was used to densify and integrate the graphite paper stacks. It has been found that the graphite paper blocks have high thermal conductivities in the paper direction and low ones perpendicular...
Zinc oxide (ZnO) nanorods were vertically grown on the surface of graphene sheets by chemical vapor deposition, and their use in a field emission device was demonstrated. In comparison with pristine graphene, the graphene/ZnO nanorod hybrid structure exhibited efficient field emission with low turn-on field, low threshold field, high emission spot density, high field enhancement factor and excellent...
Nitrogen (N) was doped into graphene oxide (GO) films at temperatures of 600–900°C under the flow of a mixture of NH 3 and Ar. The N (atomic) concentration was varied in the range of 3.63–7.45%. XPS and FTIR spectra show that there are mainly single C–N and double CN bonds in the GO sheet. Raman spectra indicate that the G band becomes closer to the position of the G band of graphite with...
In this study, we report an efficient method for synthesis of well-graphitized hollow carbon nano-onions (CNOs). CNOs were firstly fabricated by chemical vapor deposition (CVD) method at 850°C using an Fe–Ni alloy catalyst with diameters of 10–15nm. Then hollow CNOs were obtained by annealing as-prepared CNOs at 1100°C for 3h. It is found that during the CVD growth, the presence of nickel retards...
We report an in situ transmission electron microscopy study of the electrochemical behavior of few-layer graphene nanoribbons (GNRs) synthesized by longitudinal splitting the multi-walled carbon nanotubes (MWCNTs). Upon lithiation, the GNRs were covered by a nanocrystalline lithium oxide layer attached to the surfaces and edges of the GNRs, most of which were removed upon delithiation, indicating...
A method has been developed for synthesizing high-surface-area carbon nanoparticle/graphene composites. Functionalized carbon nanoparticles were anchored to the graphene planes and function as spacers to prevent the restacking of graphene sheets during drying. The composite has a layered structure in which functionalized carbon nanoparticles are sandwiched between graphene stacks. This layering leads...
A simple fabrication scheme for molecular electronic junctions is presented with multiwalled carbon nanotubes (MWCNTs) as the top electrodes. Results indicate that our approach retains the molecular character of the chosen molecules [a self-assembled monolayer of octadecanethiol on gold bottom electrodes] and opens the door for studying a wide variety of organothiol candidates for molecular electronics...
Multilayer carbonaceous nanomaterial has been synthesized using a two-step process: carbon nanodiscs/nanocones were fluorinated using either the direct reaction with pure F 2 gas or the thermal decomposition of solid fluorinating agent (TbF 4 ). Then the fluorinated parts were removed by treatment at 600°C in air. When the fluorine atoms are homogenously dispersed, using fluorination...
We have created a field emitter composed of a carbon nanotube (CNT) yarn, which was prepared by direct spinning through chemical vapor deposition and then formed into a carpet structure by tying the yarn to a conductive substrate before cutting it. The structure of the carpet is arranged to induce the tips of the CNT yarn to protrude toward the anode for maximum electron emission. The turn-on field,...
Composite sheets consisting of phenolic resin filled with a mixture of reduced graphene oxide (RGO), γ-Fe 2 O 3 and carbon fibers have been produced by compression molding. Its electrical conductivity lies in the range 0.48–171.21S/cm. Transmission and scanning electron microscopy observations confirm the presence of nano particles of γ-Fe 2 O 3 (∼9.8nm) and carbon...
Carbon xerogel spheres with millimeter-scale diameters were synthesized by a simple process using microwave radiation as the heating source. Using this type of heating it is possible to establish the gelation point of different resorcinol–formaldehyde solutions and stop the gelation step of the material at the exact time of gelation. Organic gel spheres can then be directly obtained by stirring in...
Efficiently reducible graphene oxide (GO) was obtained, even if a high degree of functionalization is present. Graphite with few defects was used as starting material and oxidized according to Hummer’s method. An extremely high I D /I G ratio for rGO of 2.8 (532nm) was observed in the Raman spectrum as a consequence of the lower defect density in GO. It was also possible to demonstrate...
Differential scanning calorimetry (DSC), X-ray diffraction, dynamic mechanical analysis (DMA) and electrical conductivity measurements were performed on multiwalled carbon nanotube/polyamide 6,6 composites with four different types of well-characterized tubes manufactured using fixed-bed catalytic processes. The tubes differed in diameter, number of walls and surface chemistry. Except for one very...
We report hexadecyltrimethylammonium bromide (CTAB)-functionalized graphene as a carbon support for Pt or PtCo nanoparticle (NP) catalysts for fuel cell cathodes. The CTAB treatment plays several critical roles in improving the cell performance: CTAB is non-covalently bound on the graphene surfaces and also functionalizes NP surfaces, thus minimizing aggregation between graphene sheets as well as...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.