Graphene Oxide Nanohybrid Research Articles

A novel interlocked Prussian blue/reduced graphene oxide nanocomposites as high-performance supercapacitor electrodes

High-quality Prussian blue/reduced graphene oxide (PB/rGO) nanohybrids were synthesized via a simple polyvinylpyrrolidone (PVP)-assisted polyol reduction method under mild conditions. The structure and composition of PB/rGO were confirmed by means of X-ray diffraction (XRD), electron microscopes (SEM and transmission electron microscopy (TEM)), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). These results indicate that ratios of starting materials allow a good control on loading and morphology of PB/graphene hybrids, and at ratio of K3Fe(CN)6/GO of 1:2, PB nanocubes get completely embedded into the defect of porous graphene matrices. Electrochemcial characterization of the PB/rGO nanocomposites with different PB/rGO weight ratios was carried out by cyclic voltammograms and galvanostatic charge–discharge in 1.0 M KNO3 electrolyte. The PB/rGO nanocomposites exhibit much higher specific capacitances than either bare PB nanocrystals or pure rGO sheets. PB/rGO (1:2) exhibits the highest specific capacitance of 251.6 F g−1 at a scan rate of 10 mV s−1 and an excellent cycling stability along with 92 % specific capacitance retained after 1000 cycle tests. The significant enhancement in electrochemical performance over PB/rGO nanocomposites can be attributed to a positive synergetic effect that the PB nanocube interlocked dispersion of rGO sheets superimposes pseudocapacitance from PB on double-layer capacitance from rGO sheets.

Correction: Sensitive and selective determination of aqueous triclosan based on gold nanoparticles on polyoxometalate/reduced graphene oxide nanohybrid

Correction for ‘Sensitive and selective determination of aqueous triclosan based on gold nanoparticles on polyoxometalate/reduced graphene oxide nanohybrid’ by Mehmet Lütfi Yola et al., RSC Adv., 2015, 5, 65953–65962.

Sensitive and selective determination of aqueous triclosan based on gold nanoparticles on polyoxometalate/reduced graphene oxide nanohybrid

A novel molecular-imprinted electrochemical sensor based on gold nanoparticles decorating polyoxometalate (H3PW12O40)/reduced graphene oxide was developed for determination of trace TCS in wastewater.

Biogenic gold nanoparticles-reduced graphene oxide nanohybrid: synthesis, characterization and application in chemical and biological reduction of nitroaromatics

The biogenic AuNPs/rGO can participate in and accelerate electron transfer, and catalyze both chemical and biological reduction of nitroaromatics efficiently.

Tuning of sunlight-induced self-cleaning and self-healing attributes of an elastomeric nanocomposite by judicious compositional variation of the TiO2–reduced graphene oxide nanohybrid

A sunlight induced self-cleaning and healable tough elastomeric hyperbranched polyurethane/TiO2–reduced graphene oxide nanocomposite is fabricated by an in situ polymerization technique.

Hydraulic power and electric field combined antifouling effect of a novel conductive poly(aminoanthraquinone)/reduced graphene oxide nanohybrid blended PVDF ultrafiltration membrane

A novel conductive PDAAQ/rGO nanohybrid blended PVDF membrane exhibited superior antifouling performance under an appropriate external electric field.

Covalent attachment of 3-(aminomethyl)pyridine to graphene oxide: a new stabilizer for the synthesis of a palladium thin film at the oil–water interface as an effective catalyst for the Suzuki–Miyaura reaction

A toluene–water planar interface has been used as an ideal template for the self-assembly of a Pd/3-(aminomethyl) pyridine-reduced graphene oxide nanohybrid.

Solid acid-reduced graphene oxide nanohybrid for enhancing thermal stability, mechanical property and flame retardancy of polypropylene

PMoA enhances the radical trapping effect of graphene.

Facile synthesis of ZnFe2O4/reduced graphene oxide nanohybrids for enhanced microwave absorption properties

The nanohybrids composed of ZnFe2O4 and reduced graphene oxide (RGO) have been synthesized by a facile one-step hydrothermal strategy. The morphology and structure of ZnFe2O4/RGO nanohybrids were characterized by transmission electron microscopy, X-ray diffraction and Raman spectra. RGO content was also determined by thermogravimetric analysis. The results confirm the formation of nanohybrids with a content of 20.4wt% RGO and extensive interfaces between small-diameter ZnFe2O4 nanoparticles and RGO sheets. The magnetic properties and electromagnetic parameters of ZnFe2O4/RGO nanohybrids were measured and the microwave absorption properties were investigated. ZnFe2O4/RGO nanohybrids exhibit the advantages of thin matching thickness and strong absorption at high frequency bands. It is demonstrated that ZnFe2O4/RGO nanohybrids can be a powerful candidate in the field of microwave absorption.

MnOx/carbon nanotube/reduced graphene oxide nanohybrids as high-performance supercapacitor electrodes

Nanohybrids consisting of both carbon and pseudocapacitive metal oxides are promising as high-performance electrodes to meet the key energy and power requirements of supercapacitors. However, the development of high-performance nanohybrids with controllable size, density, composition and morphology remains a formidable challenge. Here, we present a simple and robust approach to integrating manganese oxide (MnOx) nanoparticles onto flexible graphite paper using an ultrathin carbon nanotube/reduced graphene oxide (CNT/RGO) supporting layer. Supercapacitor electrodes employing the MnOx/CNT/RGO nanohybrids without any conductive additives or binders yield a specific capacitance of 1070 F g−1 at 10 mV s−1, which is among the highest values reported for a range of hybrid structures and is close to the theoretical capacity of MnOx. Moreover, atmospheric-pressure plasmas are used to functionalize the CNT/RGO supporting layer to improve the adhesion of MnOx nanoparticles, which results in theimproved cycling stability of the nanohybrid electrodes. These results provide information for the utilization of nanohybrids and plasma-related effects to synergistically enhance the performance of supercapacitors and may create new opportunities in areas such as catalysts, photosynthesis and electrochemical sensors.

Chemical synthesis of Fe3O4–graphene oxide nanohybrids as building blocks for magnetic and conductive membranes

Abstract We have developed a facile and scalable method for synthesising superparamagnetic Fe 3 O 4 nanocrystals (NCs) anchored on graphene oxide (GO) sheets by a co-precipitation reaction. As-synthesized Fe 3 O 4 –GO nanohybrids (NHs) were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, atomic force microscopy, field-emission scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometer. Fe 3 O 4 NCs with a narrow size distribution (4.5 ± 0.6 nm) were uniformly decorated over GO surface at high density. The GO sheets act as two-dimensional substrates and surfactants for the growth and adhesion of Fe 3 O 4 NCs. Structural changes induced in the GO due to Fe 3 O 4 decoration were clearly observed using Raman spectroscopy. The magnetic properties of Fe 3 O 4 –GO NHs could be tuned by varying Fe 3 O 4 content and a saturation magnetization as high as 39.2 emu g −1 was achieved. Fe 3 O 4 –GO NHs in their colloidal suspension were used as building blocks to fabricate magnetic and electrically conductive membranes by a vacuum-assisted assembly process.

Hyaluronic acid-decorated graphene oxide nanohybrids as nanocarriers for targeted and pH-responsive anticancer drug delivery.

A novel nanohybrid of hyaluronic acid (HA)-decorated graphene oxide (GO) was fabricated as a targeted and pH-responsive drug delivery system for controlling the release of anticancer drug doxorubicin (DOX) for tumor therapy. For the preparation, DOX was first loaded onto GO nanocarriers via π-π stacking and hydrogen-bonding interactions, and then it was decorated with HA to produce HA-GO-DOX nanohybrids via H-bonding interactions. In this strategy, HA served as both a targeting moiety and a hydrophilic group, making the as-prepared nanohybrids targeting, stable, and disperse. A high loading efficiency (42.9%) of DOX on the nanohybrids was also obtained. Cumulative DOX release from HA-GO-DOX was faster in pH 5.3 phosphate-buffered saline solution than that in pH 7.4, providing the basis for pH-response DOX release in the slightly acidic environment of tumor cells, while the much-slower DOX release from HA-GO-DOX than DOX showed the sustained drug-release capability of the nanohybrids. Fluorescent images of cellular uptake and cell viability analysis studies illustrated that these HA-GO-DOX nanohybrids significantly enhanced DOX accumulation in HA-targeted HepG2 cancer cells compared to HA-nontargeted RBMEC cells and subsequently induced selective cytotoxicity to HepG2 cells. In vivo antitumor efficiency of HA-GO-DOX nanohybrids showed obviously enhanced tumor inhibition rate for H22 hepatic cancer cell-bearing mice compared with free DOX and the GO-DOX formulation. These studies suggest that the HA-GO-DOX nanohybrids have potential clinical applications for anticancer drug delivery.

Fabrication of a nanohybrid of conjugated polymer nanoparticles and graphene oxide for biosensing of trypsin

Conjugated polymers containing triphenylamine group are synthesized via Suzuki coupling polymerization. Fluorescent-conjugated polymer nanoparticles (CPN) are prepared by reprecipitation method using the newly synthesized conjugated polymer. CPN can be encapsulated with polyarginine by electrostatic interaction. The CPN modified with polyarginine exhibit excellent interaction with graphene oxide (GO) which is chemically modified with hydrophilic groups that possesses negative charge, which, in turn, induces the quenching of the fluorescence of CPN upon formation of CPN–GO nanohybrid. Upon exposure to trypsin, the quenched fluorescence is recovered by release of CPN from the nanohybrid, because trypsin cleaves the polyarginine linkage, resulting in weakening of interaction between CPN and GO. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1898–1904

The photo-electrochemical studies of Eu3+ doped yttrium orthovanadate–zinc oxide–reduced graphene oxide nanohybrid

A new class of nanostructured photo-electrocatalyst Eu3+ doped yttrium orthovanadate–zinc oxide–reduced graphene oxide (YVO4:Eu3+–ZnO–RGO) nanohybrid was developed by a simple electrostatic self-assembly at room temperature, using ZnO, YVO4:Eu3+ and RGO as building blocks. Interaction among YVO4:Eu3+, ZnO and RGO is indicated by variation in hydrodynamic diameter (HD) and zeta potentials of the products as compared to their individual components, thus suggesting that YVO4:Eu3+–ZnO–RGO is a nanohybrid and not a physical mixture. Electrochemical response of this nanohybrid towards the redox couple of Fe(CN)63−/4− was investigated before and after UV irradiation. Apart from quenching of the green emission of ZnO in photoluminescence spectrum, which serves as a probe to monitor the interfacial electron transfer from excited ZnO to RGO, degradation in electrochemical redox process provides an additional path to monitor interfacial electron transfer.

One-step approach to prepare magnetic iron oxide/reduced graphene oxide nanohybrid for efficient organic and inorganic pollutants removal

An environmentally friendly effective technique was demonstrated to prepare iron oxide/reduced graphene oxide nanohybrid (IO/RGO) at room temperature by using banana peel ash aqueous extract as the base source and Colocasia esculenta leaves aqueous extract as the reducing agent. The nanohybrid was characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, transmission electron microscopy, vibrating sample magnetometry, Raman spectroscopy and thermal studies. The results indicated the decoration of superparamagnetic IO nanoparticles on the surface of the RGO. Both organic and inorganic pollutants were effectively removed from the contaminated water (for Pb2+ and Cd2+ within 10 min, whereas for tetrabromobisphenol A within 30 min) by IO/RGO. The study revealed that adsorption followed pseudo-second order kinetics and isotherms were well described by the Langmuir model in all the cases. The thermodynamics parameters (ΔG°, ΔS° and ΔH°) were calculated from the temperature dependent isotherms and indicated that the adsorptions were endothermic and spontaneous.

The Role of Ionic Electrolytes on Capacitive Performance of ZnO-Reduced Graphene Oxide Nanohybrids with Thermally Tunable Morphologies

In the present work, the role of the reaction temperatures on the morphologies of zinc oxide-reduced graphene oxide (ZnO-RGO) nanohybrids and their supercapacitive performance in two different aqueous electrolytes (1.0 M KCl and Na2SO4) were investigated. The ZnO-RGO nanohybrids were synthesized at two different temperatures (ca. 95 and 145 °C) by solvothermal method and labeled as ZnO-RGO-1 and ZnO-RGO-2, respectively. The structure and composition of ZnO-RGO nanohybrids were confirmed by means of X-ray diffraction, electron microscopes (scanning and transmission), X-ray photoelectron, photoluminescence, and Raman spectroscopy. These results show that the temperature allows a good control on loading and morphology of ZnO nanoassemblies in ZnO-RGO nanohybrids and at elevated temperature of 145 °C, ZnO nanoassemblies break and get completely embedded into RGO matrices. The electrochemical performance of ZnO-RGO nanohybrids was examined by cyclic voltammograms (CVs), galvanostatic charge-discharge (chronopotentiometry) and electrochemical impedance spectroscopy (EIS) in 1.0 M KCl and Na2SO4 aqueous electrolytes respectively. Combining the EIS and zeta potential behavior, a direct link between the charge transfer resistance and electrical double layers is established which is responsible for excellent capacitive performance of ZnO-RGO-2. The ZnO-RGO-2 displays high specific capacitance (107.9 F/g, scan rate = 50 mVs(-1)) in 1.0 M KCl and exhibits merely 4.2% decay in specific capacitance values over 200 cycles.

Poly(vinyl alcohol)–graphene oxide nanohybrid “pore-filling” membrane for pervaporation of toluene/n-heptane mixtures

The stability of the membrane for pervaporation separation of aromatic/aliphatic mixtures is critical for industrial applications. To improve the stability of the membrane, a “pore-filling” membrane was prepared by dynamic pressure-driven assembly of a poly(vinyl alcohol)–graphene oxide (PVA–GO) nanohybrid layer onto an asymmetric polyacrylonitrile ultrafiltration membrane. The results of the swelling experiment suggest that the pore-filling structure could effectively reduce swelling of the nanohybrid membrane. Assembly of the nanohybrid membrane by molecular-level dispersion of GO in PVA led to enhanced affinity of the membrane to aromatic compounds and thus improved performance in the pervaporation of toluene/n-heptane mixtures. Moreover, the dynamic assembly process could easily be used to adjust the separation performance by controlling the pressure, filtration time, polymer, and GO concentration.

Mesoporous single crystals Li₄Ti₅O₁₂ grown on rGO as high-rate anode materials for lithium-ion batteries.

Mesoporous single crystals Li4Ti5O12 grown on reduced graphene oxide (MSCs-LTO-rGO) nanohybrids have been synthesized by a simple hydrothermal reaction of TiO2/rGO and LiOH with subsequent annealing in Ar at 600 °C, which exhibited high specific capacity (171 mA h g(-1)) with much improved rate capability (132 mA h g(-1) at 40 C) and intriguing cycling stability (85% capacity retention after 2000 cycles).

Room-temperature synthesis and enhanced catalytic performance of silver-reduced graphene oxide nanohybrids

The synthesis of supported, ultrasmall metallic nanoparticles (NPs) is of great importance for catalytic applications. In this study, silver-reduced graphene oxide nanohybrids (Ag–rGO NHs) were prepared by reducing Ag ions and graphene oxide (GO) at room temperature using sodium borohydride (NaBH4) and trisodium citrate. The resulting products were characterized using UV–Vis spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy. The rich chemistry of GO surface provided many sites for the nucleation of Ag ions and efficiently limited their growth. Ag NPs were uniformly grown on basal planes of rGO with a high density (~1,700 NPs μm−2) and well-defined size (3.6 ± 0.6 nm) as evidenced in SEM and HRTEM studies. The resulting Ag–rGO NHs were readily dispersed in water and exhibited enhanced catalytic activity toward the reduction of 4-nitrophenol by NaBH4 in comparison to unsupported Ag NPs. The role of rGO as an excellent support for Ag catalyst is discussed.

Preparation and characterization of superparamagnetic graphene oxide nanohybrids anchored with Fe3O4 nanoparticles

We describe a novel method for the preparation of a graphene oxide (GPO) – magnetic nanoparticle (Fe3O4) (GPO–Fe3O4) nanostructured hybrids by a simple and effective method. In this method, the fabrication of multi-component nanostructure system involves covalent attachment of GPO with Fe3O4 through dopamine (do) (GPO–do-Fe3O4). Optical microscopy (OM), ultraviolet spectroscopy (UV), Fourier transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to demonstrate the successful attachment of Fe3O4 to GPO. It was found that the fabricated nanohybrid shows superparamagnetic behavior and allows rapid separation under an external-magnetic field. The FT-IR analysis of GPO–do-Fe3O4 nanohybrid shows infrared (IR) peaks characteristic of amide (CONH) link on the surface of GPO. TGA analysis clearly shows two major stages of thermal degradation, different from the pattern of observed for dopamine coated Fe3O4 surface. An EDX spectrum of GPO–do-Fe3O4 shows intense peaks for Iron (Fe) along with carbon and oxygen peaks. SEM images further support the FT-IR and TGA results and confirm the presence of Fe3O4 on GPO surface. Thus, the resultant GPO–do-Fe3O4 nanohybrid system carries both electrical and magnetic properties, which are important for applications ranging from electro-magnetic devices to biomedicine.