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A free-standing palladium/reduced graphene oxide paper (Pd/rGOP) based on one-pot co-reduction was prepared. The as-prepared Pd/rGOPs contain evenly distributed Pd particles interposing between the rGOP layers. The structure and composition of Pd/rGOP were characterized by SEM, EDX, XRD and Raman spectra. We investigated the glucose sensing performance of Pd/rGOP by chronoamperometry, the sensitivity reach as high as 6.70 µA mM−1 cm−2 with the linear range between 0.5 mM and 8 mM. The sensor also exhibits a good anti-interference ability and detection selectivity toward the interference. The proposed sensor has great potential to become a reliable tool in point-of-care medical devices.

Paper-based supercapacitors have attracted more and more attention for high electrochemical performance. However, most of them adopt sandwiched structure. Here, we prepared planar polypyrrole (PPy) coated paper-based supercapacitors by applying simple laser carving assisted method. The planar device showed a significant performance improvement (13.9 mF/cm2) compared to the sandwiched device (12.3 mF/cm2). In addition, by adjusting the polymerization time of pyrrole, the device capacity can be further increased to 87.4 mF/cm2. We firmly believed that the laser carving assisted method has a significant role in promoting the development of flexible planar electronic devices.

Effect of ferric chloride concentration on micro-nano structure surface and superhydrophobic property of filter paper was investigated by adsorption and simple immersion process. The results showed that the concentration of ferric chloride solution had great impact on the superhydrophobic property of filter paper. When the concentration was 0 mol/L, filter paper presented hydrophilicity. When the concentration was bigger than 0 mol/L, it exhibited hydrophobicity. The modified filter paper’s surface displayed advancing contact angels of 167 ± 2°, which was attributed to its’ formed micro/nano structure. This may contribute to the development in production applications.

Polyaniline (PANi) is synthesized on a highly ordered and flexible graphene paper (GNP) by in situ polymerization followed by folding the 2D composite paper into a 3D structure. The thermoelectric properties of this novel composite structure is improved as a result of the formation of an electrically connected, thermally disconnected structure due to the interconnected folds within the composite that allow electrons to conduct while discouraging phonon transport. Mechanical compaction on the folded sample is essential to produce a consolidated sample. ZT of this novel composite is an order of magnitude higher than that of neat GNP paper.

Reduced graphene oxide (RGO) papers are extensively applied in gas sensors, electronic devices, and electromagnetic shielding. However, the structures and electrical properties for RGO papers are hard to precisely fabricate and evaluate. We developed an effective method to prepare the multi-layer RGO papers by interfacial self-assembly and natural sedimentation. The thermal structural evolutions have been elaborately measured by thermogravimetric and differential scanning calorimetry (TG-DSC) analysis, X-ray diffraction (XRD) and FT-IR spectra. Consequently, the electric properties, such as conductivity, dielectric constants, and impedance, were investigated by direct LCR measurement. We think these RGO papers would be very valuable in electromagnetic interference (EMI) shielding, heat-protective materials, and flexible electrodes.

We report on the development of highly attractive nanostructured samples derived from three-dimensional microfibrous carbon paper (MFCP) uniformly decorated with multi-walled carbon nanotubes (MWNTs). We were able to show that a standard electrochemical oxidation of these 3D-nanostructures, in nitric acid solution, leads to: (i) a remarkable increase of their specific surface area reaching 208 m 2 /g as compared to 71 m 2 /g for the untreated samples, (ii) a reversal in their wettability behavior (from hydrophobic to hydrophilic), and (iii) a significant enhancement of their electrochemical activity. The MWNTs-coated MFCP material is highly promising for supercapacitor applications as it exhibits high capacitance of 165 F/g.

Two successive generations of multiwalled carbon nanotubes (MWCNT/1 and MWCNT/2) have been produced by a unique CVD procedure using fibers of a commercial carbon paper as support. MWCNTs/1 have diameters comprised between 30 and 50 nm and are about 10 μm long. They are firmly attached to the carbon paper support. MWCNTs/2 have diameters of 10–20 nm and lengths of several 100 nm. They are grown on MWCNTs/1 and have a density of about 40 nanotubes per micrometer length of MWCNTs/1. This hierarchical nanostructure may find application as support for electrochemical catalysts, especially those used in fuel cells.

A large density of multiwall carbon nanotubes (MWCNTs) has been grown on the fibers of a carbon paper using a sulfonated silane intermediary to uniformly disperse (1:1) Ni–Co catalytic sites used in the decomposition of ethylene. The nanotubes were obtained at 800 °C by Ohmically heating the carbon paper support. The MWCNTs are typically up to 20 μm in length and between 30 and 50 nm in diameter. These tubes are easily opened at room temperature, while remaining firmly attached to the carbon paper.

Multi-walled carbon nanotubes (MWCNTs) have been grown from ethylene on the fibers of carbon paper by Ohmically heating Co–Ni or Fe catalytic sites supported on the carbon fibers. MWCNTs are mainly tip-grown and have diameters ranging from 10 to 30 nm, depending on the catalyst used. The MWCNTs adhere firmly to the carbon paper with which they are in electrical contact. Cyclic voltammetry of the electrode thus formed indicates that MWCNTs behave like a graphitic material.

In order to achieve light and flexible gas sensor, we fabricated a uniform carbon nanotube paper made by multi-walled carbon nanotube and employed it as a sensing part. Referring to the transient behavior, it was clarified that the sensor response followed Langmuir isotherm, similar to the previous results prepared on a glass substrate. A repetition characteristics was quite stable and sensitivity was higher than previous one. Thus, it opens prospects for application, but it is unclear why the sensitivity is high despite the increased thickness.

The electrospinning process has been used successfully to fabricate the multiwalled carbon nanotubes (MWCNTs)-embedded polyacrylonitrile (PAN) nanofiber paper. The diameters of nanofibers decreased with increasing CNT concentration. We found large anisotropic electrical conductivity, i.e., the electrical conductivity of the carbonized nanofiber paper along the spinning direction was about three times larger than that normal to the spinning direction, in good contrast with observations that the carbonized PAN nanofiber paper without CNTs did not reveal anisotropy in electrical conductivity. This proves that CNTs in PAN nanofiber were preferentially aligned along the nanofiber axis, in excellent agreements with transmission electron microscopy observations.

Article, Chemical Physics Letters. 414(4-6):444-448 (2005)

Graphical abstract, Highlights • Structure parameters and electronic properties of graphene with kagome lattice structure is calculated. • Various XC and dispersion correction methods are used and similar results are obtained. • Pristine graphene with kagome lattice structure shows very small magnetic properties. • A kagome flat-band structure is observed near the EF. • High DOS at flat-band is mostly consisting of pz orbital and also dxz and dyz orbital contributions., In this paper, the electronic properties of a carbon allotrope, graphene with a kagome lattice structure, are investigated. Spin-polarized density functional theory (DFT) calculations with Grimme dispersion corrections were done. Bond lengths, electronic band structure, and projected density of states were calculated. Electronic band structure calculations show kagome flat-band formation with higher d-orbital contributed bonding behavior than the pristine graphene structure. The structural parameters and electronic band results of this 2D carbon allotrope show wider possible usage in many applications from desalination membranes to possible high-temperature superconductors.

Water dispersible 3-marcaptoproponic acid protected Mn2+@ZnSe QDs were applied for sensing hazardous mercury and lead ions, which acts as an acceptor for metal ions due to the strong interaction between the metal ions and thiol group (-SH). The photoluminescence (PL) intensity of Mn2+@ZnSe QDs was strongly quenched with Hg2+ and Pb2+ (0-100 μL). The average PL lifetime of Mn2+@ZnSe was shortened with Hg2+ concentrations whereas increased with Pb2+ concentrations. A filter paper-based sensor was also prepared and successfully tested for sensing via colorimetric and fluorometric detection methods. The system provided a new possibility for dual response ions detection in real samples.

The practical application of superhydrophobic coatings on glass is usually restricted by their poor wear resistance due to the insufficient adhesion. A double-silica-layered structure was proposed to reinforce the coating adhesion on glass substrate. The wettability, surface morphologies, and chemical composition were investigated by water contact angle measurement, scanning electron microscopy (SEM), and fourier transformed infrared (FTIR) spectroscopy. The prepared superhydrophobic coating displays a good wear-resistance by emery paper and sand abrasion, which also has excellent thermal stability and UV resistance. This strategy shows a bright future for durable superhydrophobic coating on glass.

Graphene and graphite are of great interest in materials science. Using chemical vapor deposition at various CH4:H2 ratios, we synthesized materials with graphene-laminated architectures, ranging from graphene to graphite. A lower proportion of CH4 and lower synthesis temperature produced fewer graphene layers. The transparent properties changed from transparent to semi-transparent, black, and silver as the number of graphene layers was increased. The sheet electrical resistivity ranged from 106 to 0.2 Ω □−1, and the smaller resistivity was nearly equaled as the values of highly orientated pyrolytic graphite and glassy carbon. The graphene-laminated materials featured a wide range of transmittance, reflectance, and electrical conductance properties.

Chemical etching on copper surface is essential as a pre-treatment for single-layer graphene growth by chemical vapor deposition (CVD). Here, we investigated the effect of chemical etching treatment on copper foils for single-layer graphene CVD growth. The chemical etching conditions, such as the type of chemical etchants and the treatment time, were found to strongly influence the graphene domain size. Moreover, a drastic change in the layer structure of graphene sheets, which was attributed to the surface morphology of the etched copper foil, was confirmed by graphene transmittance and Raman mapping measurements.

Ambient plasma is applied to graphite oxide electrodes directly to improve electrochemical properties for supercapacitor applications. Surface morphology of the electrodes after the plasma treatment changes dramatically and amount of oxygen reduced significantly, demonstrating a reduction effect on the graphite oxide electrode by the ambient plasma. Equivalent series resistance of the electrode also reduced from 108 Ω to 84 Ω after the plasma treatment. Corresponding specific capacitance, therefore, increases from 0.45 F cm −2 to 0.85 F cm −2 , proving that the ambient plasma treatment is very efficient, clean, economic, and environment-friendly method to reform the graphite oxide electrodes directly for the supercapacitor applications.

Silica has been used as support material with many photocatalytic materials. In this study, silica polymorphs on graphene and epoxy graphene were studied using Density Functional Theory (DFT) to determine the interfacial and optical properties of the composite material. The powder diffraction patterns and Raman spectra for the silica polymorph structural models as well as graphene and epoxy graphene monoxide were generated using Material Studio (2016), and the GGA in PBE first principle method. The electronic and optical properties as well as work function analysis of the polymorphs with graphene and epoxy graphene monoxide starting molecules together with the layers systems were compared. In Our findings the optical properties of the layers generated were sensitive to the visible light in both epoxy-graphene monoxide and graphene composites.

We propose facile synthesis methods to prepare two three-dimension (3D) multi-porous graphene structures including graphene aerogel and graphene nanowalls. The graphene aerogel was prepared via the hydrothermal reduction and tert -butanol freeze-drying. The graphene nanowalls were prepared by growing the obtained graphene aerogel via a plasma enhanced chemical vapor deposition (PECVD). High specific surface areas of these two structures up to 795 m 2 /g were obtained by BET analyses. The crystallized, multi-porous, and thermal stable features of these two 3D graphene structures were verified via the X-ray diffraction, SEM, Raman spectroscopy and thermal gravity analysis characterizations.

The pure MoS 2 and MoS 2 @reduced graphene oxide were synthesized on commercially available Ti plate by one-step hydrothermal method. The hole microspheres were successfully synthesized. The resulting MoS 2 @reduced graphene oxide electrode on Ti plate exhibited higher catalytic activity than pure MoS 2 electrode on Ti plate for hydrogen evolution reaction. In addition, the excellent cycling stability was also obtained in MoS 2 @reduced graphene oxide electrode on Ti plate. Such enhanced catalytic activity and excellent cycling stability occurred due to the abundance of catalytic edge sites, high specific surface area and the unique synergic effects between the MoS 2 and reduced graphene oxide.

SiC nanowires were fabricated by heat-treating a graphene/Si configuration without using catalyst. This configuration was obtained by depositing few-layer graphene powders on Si (1 1 1) wafer using arc discharge method. The coverage rate of graphene on Si substrate can be controlled by arc discharge duration. The micro morphology observation and spectra characterization indicate that few-layer graphene powders provide carbon source in both nucleation step and growing step through vapor-solid process. The present results show that few-layer graphene can be used to mass-produce 3C-SiC nanowires with diameters from 10 to 50 nm, which is useful for applications of nanodevices and composite materials.

Poly(vinyl alcohol), PVA, polymer was successfully combined with graphene oxide (GO) and thermally reduced graphene oxide (RGO), respectively, to make composites and characterized for supercapacitor applications. PVA-RGO composite shows excellent electrochemical properties compared to PVA-GO composite. The capacitance of 190 Fg −1 is obtained from PVA-RGO composite which is larger than that (13 Fg −1 ) of PVA-GO composite. Electrochemical impedance of PVA-RGO is more than ten times smaller than that of PVA-GO at 20 kHz, demonstrating that PVA-RGO composite has a great advantage for supercapacitor applications compared to PVA, GO, RGO, and PVA-GO composite.

Nanohole graphene oxide (NHGO) was obtained in a homogeneous aqueous mixture of graphene oxide (GO) and H 2 O 2 at 120 °C. Supercapacitors were fabricated as the electrode material by using NHGO. A specific capacitance of 240.1 F g −1 was obtained at a current density of 1 A g −1 in 6 m KOH electrolyte and specific capacitance remained 193.6 F g −1 at the current density of 20 A g −1 . This was attributed to reducing the inner space between the double-layers, enhanced ion diffusion and large specific surface area. Supercapacitor prepared with NHGO electrodes also exhibited an excellent cycle stability.

Facile synthesis of graphene–Nb2O5 composite has been reported. Graphene oxide was prepared by the modified Hummer's method. The metal oxide (Nb2O5) was introduced to the graphene to form the composite by the hydrothermal method. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared (FTIR) and thermo gravimetric analysis (TGA). SEM and TEM results revealed that the metal oxide particles are uniformly dispersed on the surface of thin sheets of well-defined multilayered graphene structure. Thermal stability of the graphene metal oxide nanocomposites was also investigated. The CV measurements reveal a significant enhancement in the specific capacitance reaching 321 Fg−1 at a scan rate of 10 mV s−1. With promising electrochemical characteristics, Nb2O5 decorated graphene nanocomposite are explored as potential electrode material for supercapacitor applications.

Nanocomposite of poly(vinylidene fluoride-co-hexafluoropropylene) incorporated with titanium dioxide-modified reduced graphene oxide sheets (rGO–TiO 2 /PVDF-HFP) was prepared by in situ assembling TiO 2 on graphene oxide (GO), and its dielectric properties were carefully characterized. The GO layers were completely coated with amorphous TiO 2 . The dielectric permittivity increased stably as rGO–TiO 2 content increased, and the loss was low at low frequencies. TiO 2 inter-layer acted as an inter-particle barrier to prevent direct contact of rGO, which provided a new simple way for tuning the dielectric properties of polymer composites with low dielectric loss by controlling the structure of fillers.

Few-layer graphene has been prepared by electrochemical intercalation of graphite cathode using Na + / dimethyl sulfoxide complexes as intercalation agent. By adding thionin acetate salt into the electrolyte, the exfoliated graphite is stabilized and further exfoliated into few-layer graphene. Raman and X-ray photoelectron spectra indicate that the graphene material has lower content of defects and oxygen functional groups compared with that obtained by chemically reducing graphene oxide. The graphene paper produced by filtration shows an electrical conductivity of 380 S m 1 , which is forty times larger than that of the graphene material produced by chemical reduction of thionin-stabilized graphene oxide.

Both suspended graphene and graphene on Si-terminated (0 0 0 1) SiC system with the lattice parameter of 4.92 A (strained) or 5.33 A (unstrained) were simulated using first-principles method to investigate the substrate effect on thermal transport properties of graphene on SiC. The thermal conductance of graphene on substrate is figured out to have a dramatical reduction, with a maximum value of 42% which can only be found on the buffer graphene layer, compared to that of suspended graphene at room temperature. The results will help to accelerate application of graphene in the situation where substrate effect cannot be ignored.

Multiwalled carbon nanotubes (MWCNTs), with typical lengths of 20 μm and diameters of 40 nm, have been grown directly on carbon paper backing. A sulfonic acid–silicate intermediate was used to deposit Pt particles on the MWCNTs in order to obtain an electrode that could be used in electrocatalysis. The electrical path between the Pt nanoparticles (1.2 ± 0.3 nm in size) and the carbon paper, through the MWCNTs, was demonstrated by cyclic voltammetry. The Pt surface density of a typical MWCNT composite electrode is estimated to be about 25% of that of an ELAT electrode from E-TEK, containing 0.4 mg Pt/cm 2 .

The exemplary properties of graphene and the potential inclusion of nanoparticles have suggested applications in energy storage, catalysts and sensing. A critical feature of the performance of these nanocomposites is the distribution of nanoparticles and the exposed area of the graphene. Here we report a computational analysis exploring the effect of the dispersion of nanoparticles between layers of graphene, characterizing both solvent accessible surface area (SASA) and inter-graphene adhesion energy (ΔEg). We find a maximum number of nanoparticles before the accessible graphene surface area decreases, and a limit where the system separates as the graphene layers no longer ‘stick’.

Large-area, high-quality graphene was grown via thermal chemical vapour deposition from ethene on Cu substrates at 850 °C. The quality of the graphene was assessed using Raman spectroscopy, SEM and electrical characterisation. The Raman spectroscopy yielded excellent results with an average 2D/G ratio of ∼2.75 and 2D FWHM of ∼35 cm −1 in the flake centres, indicative of single layer growth. Graphene field effect transistors were fabricated from in situ grown graphene lines, displaying mobilities of 1100 cm 2 V −1 s −1 and 700 cm 2 V −1 s −1 at room temperature for holes and electrons, respectively, underlining the high quality of the graphene.

A new electrode material composed of graphene oxide (GO) and pristine graphene (PG) was simply fabricated, and a very fast electron transfer kinetics on GO/PG electrodes was exhibited. This improved electrochemical performance of the GO/PG composites should be ascribed to a unique structure formed when GO combined with PG nanosheets serving as patches.

We have synthesized graphene by reducing carbon dioxide in magnesium and calcium metal flames. The as-prepared graphene has been used as conductive additive to improve the electrical conduction of activated carbon-based supercapacitor electrodes. The graphene/activated carbon composite electrode showed an outstanding specific capacitance of 220 and 180 F g (1) at a current density of 0. 1 A g (1) in 6 M KOH electrolyte when using graphene obtained in magnesium and calcium flames, respectively. (C) 2013 Elsevier B.V. All rights reserved.

High pressure Raman study on graphene nanoplates, graphite and micro-graphite has been carried out in a diamond anvil cell. A phase transformation has been observed in graphene nanoplates at 15 GPa in the experiments with or without pressure medium, which can be explained by the interlayer coupling with sp3 bonds formed in the material. For graphite and micro-graphite, the transition pressure is 19 GPa. Different transition pressures for them are attributed to the thickness difference. The lower transition pressure in graphene nanoplates has been discussed in the framework of the special limited-number layer structure and nucleation process in phase transition.

We describe a process of co-reduction to reduce dispersed graphene oxide (GO) and single-walled carbon nanotubes (SWNTs) simultaneously for preparation of hybrid electrodes for graphene supercapacitors. The SWNTs are in between the inter-layer space of graphene sheets as a spacer to prevent effectively restacking of graphene that often limits seriously the electrochemical performance of graphene supercapacitors. The SWNTs also act as conductive binders to improve the electrical conduction of the electrode. A high specific capacitance of 261 F g−1 for a single electrode and specific energy density of 123 W h kg−1 measured in the two-electrode configuration have been obtained in ionic liquid (EMI-TFSI).

We synthesized a new composite of poly sodium 4-styrenesulfonate intercalated graphene oxide for energy storage devices by controlling oxidation time in the synthesis of graphite oxide. Specific capacitance was improved from 20 F/g of the previous composites to 88 F/g of the new composite at the current density of 0.3 A/g. The capacitance retention was 94% after 3000 cycles, indicating that the new composites of high cyclic stability, prominent performance as electric double layer capacitor, and even low resistance could be an excellent carbon based electrode for further energy storage devices.

Nonlinear optical and optical limiting properties of three graphene materials (pure graphene, graphene oxide, reduced graphene oxide) covalently functionalized by zinc phthalocyanine were studied in nanosecond and femtosecond regimes. In nanosecond regime, reduced graphene oxide–phthalocyanine hybrid shows better optical limiting effect than the other two hybrids. In femtosecond regime, graphene oxide–phthalocyanine shows the best nonlinear optical properties among the three hybrid materials. Based on Z-scan and transient absorption measurements, the mechanisms for nonlinear optical property were analyzed for these materials. Compared with the other two hybrids, reduced graphene oxide–phthalocyanine hybrid is a better candidate in the application of optical limiter.

We investigated the valence band structure of poly(sodium 4-styrenesulfonate) intercalated graphite oxide composites by photoemission spectroscopy. Typical sp 2 hybridized π state near Fermi level as seen in graphite was compressed, indicating a charge transfer from sp 2 carbon to oxygen bonded to the carbon backbone. A downshift of highest occupied molecular orbital of the composites opened a gap of 1.24 eV below Fermi level. Work function of the composites obtained from the secondary electrons cutoff was smaller than that of graphite oxide by 0.4 eV, explaining the high performance of electric double layer capacitance of the composites compared with graphite oxide.

Surface enhanced Raman scattering (SERS) of graphene deposited by the Au nanoparticles were investigated with the 785 nm excitation. The SERS spectra are used to extract information of graphene. It was shown that the artificial defects were effectively induced by depositing Au nanoparticles on graphene surface. Meanwhile, the Au nanoparticle can quench the fluorescence of substrate and enhance the Raman signals of graphene drastically. The adatom-induced defects in graphene cause a significant Raman intensity in D and D′ band. This shed light on the understanding of the structural characteristics of graphene-based nanocomposite and the interaction between graphene and metal adatoms.

Large-scale production of graphene sheets has been achieved by direct current arc discharge evaporation of pure graphite electrodes in various H 2 –inert gas mixtures. The as-prepared few-layer graphene sheets have high purity, high crystallinity and high oxidation resistance temperature. Their electrochemical characteristics have been evaluated in coin-type cells versus metallic lithium. The first cell discharge capacity reached 1332 mA h g −1 at a current density of 50 mA g −1 . After 350 cycles, the discharge capacity still remained at 323 mA h g −1 . Graphene sheets produced by this method should be a promising candidate for the electrode material of lithium-ion batteries.

The time-dependent structural evolution of graphene domains on copper foils by ambient pressure chemical vapor deposition (CVD) is studied in detail. The single crystalline graphene domains up to tens of micrometer are obtained, and carbon–copper (C–Cu) alloyed nanoparticles have been firstly founded out to act as intermediates which supply carbon species for the growth of graphene domains. The layer number and size can be adjustable by controlling growth time. On the basis of results, the surface adsorption combined with an epitaxial growth procedure is proposed to explain the growth of graphene on copper under the ambient pressure CVD. Our work presents a significant progress in production of graphene with controlled structure.

We report a direct synthesis of single-layer, bi-layer, and multi-layer graphene films on a nickel grid surface by chemical vapor decomposition of liquid precursor benzene. The direct route, by avoiding several wet chemical steps and accompanying mechanical stresses and contamination common to all presently reported graphene transfer to microscopy grid method, enables providing pristine microstructure information for as-prepared graphene films. A liquid precursor based growth route opens a new door to tailor the electronic properties of graphene by doping heteroatoms using various organic liquids containing the dopant atoms.

Large area and few to multi-layer graphene sheets were synthesized on a bimetallic catalyst system via radio-frequency chemical vapor deposition (RF-CVD). Synthesis conditions were varied and their effects on the morphological properties of the graphene structures were observed. As the flow rate of the hydrocarbon was varied, the diameter of the graphene structures increased from a few hundred nanometers to a few micrometers. The number of graphene layers was also found to be dependent on the hydrocarbon concentration. This method shows great potential for the synthesis of large area few-layer graphene sheets, which can be used in various electronic applications.

A method was developed to chemically functionalize graphene sheets by silylation. The graphene oxide sheets were silanized with N-(trimethoxysilylpropyl) ethylenediamine triacetic acid. Then the silanized graphene oxide sheets were reduced to produce water-soluble graphene derivatives (EDTA–graphenes). Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the structures and properties of the EDTA–graphenes and to monitor changes in the surface morphology and chemical and physical characteristics of graphene at different stages of the silylation reaction. The EDTA–graphenes showed improved dispersion in water and an EDTA–graphene film with a well-layered structure and high conductivity was fabricated.

Electronic band structures of viologen-doped graphene have been investigated. Pristine graphene film, synthesized by chemical vapor deposition (CVD), showed numerous oxygen-related functional groups, and was annealed to remove oxygen content. Two species of viologen, di-cationic and mono-cationic, were observed in the viologen-doped graphene. The work function of the CVD graphene was dramatically decreased by 1.1 eV after viologen doping. Viologen, therefore, is a strong n-type dopant for graphene, and this report shows the first direct evidence of changing the work function of viologen-doped graphene by cutting-off the kinetic energy of secondary electrons.

The chemical doping of monolayer and bilayer graphene with aluminium, silicon, phosphorus and sulfur was investigated. Si-doped graphene has the lowest formation energy although it is semimetallic. P-doped graphene has a magnetic moment of 1 μ B and for 3 at.% of doping the band gap is 0.67 eV. Al-doped graphene is very unstable but it is an attractive material because it is metallic. To reduce the formation energies of the substitutional defects we investigated the formation of interlayer bonds in bilayer graphene. Phosphorus forms the strongest bonds between layers giving particular stability to this material. P-doped bilayer graphene has a gap of 0.43 eV but it is has no magnetic moment.

Graphene nanosheets–polystyrene nanocomposites were prepared by in situ emulsion polymerization and reduction of graphene oxide using hydrazine hydrate. PS microspheres covalently linked to the edges of graphene nanosheets. The polystyrene-absorbed graphene has been dispersed well in the solvents of toluene and chloroform. The nanocomposites display high electrical conductivity, and a considerable increase in glass-transition temperature and good thermal stability of PS are also achieved. The facile and environmental-friendly technique presented here is an effective and promising method of functionalization of graphene sheets by polymers or other compounds.

The electronic structure of poly(sodium 4-styrenesulfonate) intercalated graphite oxide (PSSGO) in the vicinity of the Fermi level was investigated using ultraviolet photoemission and inverse photoemission spectroscopies. The conduction band density of states for PSSGO is similar to that of graphite, indicating facile electron transfer from electrolyte ions to the PSSGO electrode in energy storage device applications. The in situ band gap of 1.9 eV observed was smaller than that of graphite oxide by 0.4 eV, helping to explain the high performance of electric double layer capacitor of PSSGO compared with graphite oxide.

Time and wavelength-resolved laser-induced incandescence (LII) study is performed in a titania nanoparticle-generating flame under different laser fluences. Measurements of the flame light emission are performed during the laser pulse and at short delay times. The results cannot be explained within the traditional description of heat exchange mechanisms between particles and the environment. The paper suggests to distinguish electron and phonon temperatures in the nanoparticles in order to reconcile observations. The fundamental phenomenon responsible for a possibility of that temperature difference and its implication to pyrometry measurements in flames is discussed and justified in the paper.