Graphene Oxide Polypyrrole Research Articles

Sorption of Thorium Using Magnetic Graphene Oxide Polypyrrole Composite Synthesized from Water Hyacinth Roots

Polypyrrole magnetic graphene oxide (PPy/MGO) composites have been synthesized from a natural source (water hyacinth roots) using polymerization technique for Th(IV) ions pre-concentration from aqueous solutions. The effects of controlling factor have been studied using the batch technique. The obtained results show that the maximum Th(IV) adsorption capacity by PPy/MGO composite is 277.8 mg/g at pH 4, which is higher than traditional adsorbents. PPy/MGO composite also presents excellent regeneration/reuse property. The PPy/MGO was thoroughly characterized by a number of techniques namely, Fourier transforms infrared, Raman, as well as X-ray diffraction, thermogravimetric and Energy-Dispersive X-ray (EDX). Due to the high adsorption capacity of Th (IV), PPy/MGO composite can be used in nuclear fuel achievement and for Th(IV) environmental pollution cleanup.

Determination of Sulfonamide Residues in Honey and Milk by HPLC Coupled with Novel Graphene Oxide/Polypyrrole Foam Material-Pipette Tip Solid Phase Extraction

A rapid, sensitive, and economical pipette tip solid phase extraction (PT-SPE) based on graphene oxide/polypyrrole (GO/PPy) coupled with high performance liquid chromatography (HPLC) was developed for the extraction and determination of sulfonamides (SAs) in honey and milk samples. The PT-SPE procedure involved only 3.0 mg of adsorbent, 3 min adsorptive extraction time, and less than 1.0 mL of solvent consumption (sample, washing, or eluent). Under the optimal conditions, good linearities (0.01–10.00 μg mL−1) were obtained with correlation coefficients (r) > 0.9996. The limits of detection (S/N = 3) were in the range of 1.04–1.50 ng mL−1. Meanwhile, the proposed method was successfully applied for the analysis of SAs in honey and milk with average recoveries within 62.3–109.0% and relative standard deviations less than 11.2%. The results demonstrated that the developed PT-SPE-HPLC method was suitable for the analysis of SAs in complex matrix due to its high sensitivity and accuracy.

Sorption of thorium using magnetic graphene oxide polypyrrole composite synthesized from natural source

ABSTRACTPolypyrrole magnetic graphene oxide (PPy/MGO) composites has been synthesized from natural source (water hyacinth roots) using polymerization technique for Th(IV) ions pre-concentration from aqueous solutions. The effects of controlling factor have been studied using batch technique. The obtained results show that the maximum Th(IV) adsorption capacity by PPy/MGO composite is 277.8 mg/g at pH 4, which is higher than traditional adsorbents. PPy/MGO composite also presents excellent regeneration/reuse property. Due to the high adsorption capacity of Th(IV), PPy/MGO composite can be used in nuclear fuel achievement and for Th(IV) environmental pollution cleanup.

Polypyrrole modified Fe0-loaded graphene oxide for the enrichment of uranium(vi) from simulated seawater.

Extraction of uranium(vi) from seawater has attracted much attention for its potential use in the nuclear energy field. In this work, we synthesized graphene oxide-polypyrrole (GO-PPy) through pyrrole monomer polymerization on graphene oxide (GO) with an aqueous solution at low temperature and prepared reduced graphene oxide-polypyrrole-zero-valent iron (rGO-PPy-Fe0) composites by chemical deposition. We characterized rGO-PPy-Fe0 using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The rGO-PPy-Fe0 composites were investigated for the removal of uranium from aqueous solution and simulated seawater. The experimental results demonstrated that the rGO-PPy-Fe0 adsorbent possessed a superior capacity for the adsorption of uranium at mg g-1 and μg g-1 at the pH value of seawater. The adsorption process conformed to the pseudo-second-order rate equation and the Langmuir isotherm model. Based on X-ray photoelectron spectroscopy (XPS), we revealed the possible adsorption mechanism of uranium onto rGO-PPy-Fe0, which simulated a prospective potential of the adsorbent in seawater.

All-porous heterostructure of reduced graphene oxide–polypyrrole–nanoporous gold for a planar flexible supercapacitor showing outstanding volumetric capacitance and energy density

We propose a new prototype of flexible planar supercapacitor with highly conductive all-porous morphology of all the electroactive layers that shows outstanding volumetric stack capacitance (245.34 F cm−3) and energy density (98.48 mW h cm−3).

85 MeV C6+ swift heavy ion irradiation of in-situ reduced graphene oxide–polypyrrole nanotubes nanocomposite films for supercapacitor electrodes

Hybrid nanocomposites of reduced graphene oxide (RGO) and polypyrrole nanotubes (PPyNTs) have been synthesized by in-situ reduction of graphene oxide. The nanocomposite films are modified by swift heavy ion irradiation with 85 MeV C6+ ions at different fluences of 6 × 1010, 3.6 × 1011, 2.2 × 1012 and 1.3 × 1013 ions cm−2. Morphological, structural, thermal and electrical properties of the irradiated nanocomposites have been investigated by FESEM, HRTEM, XRD, thermogravimetric analyzer and conductivity measurements. The BET specific surface area and porosity of the nanocomposites have been determined by N2 adsorption-desorption measurements. The fluence dependent electrochemical performance of the irradiated nanocomposites as electrodes has been studied by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. The electrochemical studies reveal that the capacitive properties improved upto a fluence of 2.2 × 1012 ions cm−2 and decreases at higher fluence. A highest specific capacitance of 346 F g−1 and cyclic stability of 89% is achieved for the irradiated nanocomposite compared to 299 F g−1 and 77% of that of pristine. The increase of capacitive performance may be ascribed to the increase in surface area and pore size of the pristine electrode with increasing irradiation fluence, which extends the ion transport from the surface to the bulk of the electrode. Decrease in the diameter of PPyNTs is observed from FESEM images with increase in ion fluence, which may also contribute to higher charge storage by increasing the overall surface area of the electrode.

Functionalized graphene oxide–polypyrrole–chitosan (fGO–PPy–CS) modified screen-printed electrodes for non-enzymatic hydrogen peroxide detection

Functionalized graphene oxide (fGO) was synthesized and subsequently used for synthesis of nanocomposite with polypyrrole (PPy) and chitosan (CS) to give fGO–PPy–CS nanocomposites. Screen-printed carbon electrodes were then modified with these nanocomposites to construct an unprecedented hydrogen peroxide (H2O2) sensor. Cyclic voltammetry (CV) and amperometric response demonstrated that the composite materials hold potential for electrocataytic reduction towards H2O2. Under optimal experimental conditions, the amperometric response of the fGO–PPy–CS sensor was linearly proportional to H2O2 in the range of 2.5–200 μM with a detection limit of 1.95 μM (S/N = 3). The present study provides new opportunities for fGO–PPy–CS-modified electrodes to probe the improved non-enzymatic detection of H2O2. It further broadens the applications of graphene-based conducting composites in the field of sensors and biosensors for diverse applications.

A High Performance Supercapacitor Based on Graphene/Polypyrrole/Cu2O–Cu(OH)2 Ternary Nanocomposite Coated on Nickel Foam

A simple and low-cost electrochemical deposition method is used to prepare reduced graphene oxide/polypyrrole/Cu2O–Cu(OH)2 (RGO/PPy/Cu2O–Cu(OH)2) ternary nanocomposites as the electrode material for supercapacitor application. First, graphene oxide–polypyrrole (GO/PPy) nanocomposite is electrochemically synthesized on Ni foam by electro-oxidation of pyrrole monomer in an aqueous solution containing GO and Tiron. Subsequently, the GO/PPy film is converted to the corresponding reduced form (RGO/PPy) by an effective and eco-friendly electrochemical reduction method. Then, a thin layer of Cu2O–Cu(OH)2 is formed on RGO/PPy film by chronoamperometry. The RGO/PPy/Cu2O–Cu(OH)2 nanocomposite is characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectra (FT-IR). SEM images show that Cu2O–Cu(OH)2 nanoparticles are dispersed on the surface of RGO/PPy film with an average particle size o...

Spontaneous, Straightforward Fabrication of Partially Reduced Graphene Oxide-Polypyrrole Composite Films for Versatile Actuators.

A facile one-step approach has been developed to fabricate partially reduced graphene oxide-polypyrrole (prGO-PPy) film via self-oxidation-reduction strategy, in which graphene oxide acts as the oxidant to polymerize pyrrole into PPy leading to the spontaneous partial reduction of GO and cross-linking between prGO and PPy via π-π interaction. With the convenient preparation method, a well controlled designed asymmetric actuator based on GO (or G)/prGO-PPy film with excellent humidity and electrochemical responses has been achieved for versatile stimulated actuations that will also play essential roles in advanced actuators for many important intelligent applications.

Electrochemical codeposition of graphene/polypyrrole composites on carbon paper for electrochemical capacitors

A simple electrochemical codeposition technique has been introduced to fabricate graphene oxide/polypyrrole (GO/PPy) composites. To increase the adsorption of colloidal GOs at the liquid–liquid interface, the organic supporting electrolyte like benzenesulfonate sodium (BS) is added in GO/pyrrole micelle solution, which does not induce the flocculation sedimentation of GO at elevated ionic strength. The narrow size distribution of GO/pyrrole/BS micelles is benefit for uniform codeposition of GO/PPy on the carbon fiber surface. Moreover, the GO nanosheets and benzensulfonate have been incorporated into composites as mixture dopants, which increased the growth orientation of PPy in electropolymerization process and result in more loose structure for ionic transportation. The composites electrodes exhibit high specific capacitance, good cyclic stability after electrochemical reduction of graphene oxide (RGO). The specific capacitance of composite electrode with low mass density still reaches 358 F/g at scan rate of 10 mV/s within an electrochemical windows of 1.0 V. The strong interaction effect between two components resists the mechanical deformation effect and exhibits only 7.1% decay at a charge/discharge current of 3 A/g after 1000 cycles. At increasing the mass density of composites to 8.4 mg/cm2, the areal capacitance of electrode almost grow linearly to 1.286 F/cm2, which is more than triple that of BS-doped PPy with the same mass density. The high capacity of the composite electrode exerts the potential applications in capacitive deionization, microbial fuel cell or even capacitive energy storage.

Conversion of uniform graphene oxide/polypyrrole composites into functionalized 3D carbon nanosheet frameworks with superior supercapacitive and sodium-ion storage properties

Two-dimensional (2D) graphene oxide/polypyrrole (GO/PPy) hybrid materials derived from in-situ polymerization are used as precursors for constructing functionalized three-dimensional (3D) porous nitrogen-doped carbon nanosheet frameworks (FT-PNCNFs) through a one-step activation strategy. In the formation process of FT-PNCNFs, PPY is directly converted into hierarchical porous nitrogen-doped carbon layers, while GO is simultaneously reduced to become electrically conductive. The complementary functions of individual components endow the FT-PNCNFs with excellent properties for both supercapacitors (SCs) and sodium ion batteries (SIBs) applications. When tested in symmetrical SC, the FT-PNCNFs demonstrate superior energy storage behaviour. At an extremely high scan rate of 3000 mV s−1, the cyclic voltammetry (CV) curve retains an inspiring quasi-rectangle shape in KOH solution. Meanwhile, high capacitances (∼247 F g−1 at 10 mV s−1; ∼146 F g−1 at 3000 mV s−1) and good cycling stability (∼95% retention after 8000 cycles) are achieved. In addition, an attractive SIB anode performance could be achieved. The FT-PNCNFs electrode delivers a reversible capacity of 187 mAh g−1 during 160th cycle at 100 mA g−1. Its reversible capacity retains 144 mAh g−1 after extending the number of cycles to 500 at 500 mA g−1.

Efficient removal of phenol and aniline from aqueous solutions using graphene oxide/polypyrrole composites

A novel approach was developed to fabricate graphene oxide/polypyrrole (GO/PPy) composites via dielectric barrier discharge (DBD) plasma technique in nitrogen and room temperature conditions, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) in details. The sorption of phenol and aniline on the GO/PPy composites from aqueous solutions was investigated as a function of contact time, solid content, pH and initial concentrations of sorbates. The sorption capacities of phenol and aniline on the GO/PPy composites were much higher than those of phenol and aniline on many of today's materials. The sorption of phenol and aniline on GO/PPy composites obeyed the Langmuir model, and was mainly attributed to ion exchange, π–π electron donor–acceptor (EDA) interaction, hydrophobic interaction and Lewis acid–base interaction. The thermodynamic parameters calculated from the temperature-dependent sorption isotherms suggested that phenol and aniline sorption on GO/PPy composites was an endothermic and spontaneous process. Moreover, GO/PPy composites could be regenerated through the phenol and aniline desorption by ethanol, and cycling reused without obvious decrease of sorption capacity. All these results indicated that the GO/PPy composites were suitable materials for the preconcentration of phenol and aniline from aqueous solutions in environmental pollution management.

Facile fabrication of graphene–polypyrrole–Mn composites as high-performance electrodes for capacitive deionization

Reduced graphene oxide–polypyrrole–MnO2 composites are facilely prepared for high performance electrodes for capacitive deionization.

A new graphene oxide/polypyrrole foam material with pipette-tip solid-phase extraction for determination of three auxins in papaya juice

A new material, graphene oxide/polypyrrole (GO/Ppy), was synthesized by mixing graphene oxide and polypyrrole in a specific proportion. It possesses a unique structure similar to that of foam. A homemade pipette-tip solid-phase extraction (PT-SPE) device, which is more simple and convenient than traditional devices, was used for saving reagents and operation time. When GO/Ppy was used as the adsorbent of PT-SPE for determining three auxins (indole-3-propionic acid, indole-3-butyric acid, and 1-naphthaleneacetic acid) present in trace amounts in papaya juice, it showed high affinity and adsorption capacity for all the three auxins. GO/Ppy-PT-SPE also had a significant capacity for eliminating the interferences from the papaya juice matrix. Under optimized conditions, a good linearity of auxins was obtained in the range 16.3–812.5ngg−1; the average recoveries at the three spiked levels of the three auxins ranged from 89.4% to 105.6% with the relative standard deviations ≤3.0%. Meanwhile, six papaya juice samples with different growth stages were analyzed under optimum conditions, and trace auxins in the range 18.3–100.6ngg−1 were observed. Because of its high selectivity, simplicity, and reliability, the GO/Ppy-PT-SPE method developed herein can be potentially applied for determining trace auxins in complex biological samples.

Nitrogen-doped carbon-graphene composites enhance the electrocatalytic performance of the supported Pt catalysts for methanol oxidation.

A novel nitrogen doped carbon-graphene support for a direct methanol fuel cell was synthesised via thermal decomposition of the graphene oxide-polypyrrole composite. The supported catalysts show considerable enhancement of activity and stability towards the methanol electro-oxidation reaction. Physical characterizations reveal that the enhanced performance was due to a uniform particle dispersion and modified electronic structure of platinum nanoparticles by the support.

Graphene oxide/polypyrrole composites for highly selective enrichment of U(vi) from aqueous solutions

Graphene oxide/polypyrrole (GO/PPy) composites were synthesized via a dielectric barrier discharge (DBD) plasma technique in nitrogen conditions, and characterized by scanning electron microscopy (SEM), Raman spectroscopy, thermal gravimetric analysis (TGA), Fourier transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The sorption of U(VI) ions on GO/PPy composites from aqueous solutions was investigated as a function of contact time, pH, ionic strength and U(VI) initial concentrations. The sorption capacity of U(VI) on GO/PPy composites was much higher than those of U(VI) on GO, PPy and many other materials of today. The sorption of U(VI) on GO/PPy composites obeyed the Langmuir model, and was mainly attributed to surface complexation via the coordination of U(VI) ions with oxygen- and nitrogen-containing functional groups. The selectivity sorption of U(VI) ions on GO/PPy composites in the presence of other metal ions (i.e., Co(II), Ni(II), Cd(II), Sr(II), Zn(II)) indicated an overall preference for U(VI) ions. Moreover, the GO/PPy composites could be regenerated through the desorption of adsorbed U(VI) ions by using 1.0 M HCl solution, and cycling reused without an obvious decrease of sorption capacity. All these performances indicate that GO/PPy composites are suitable materials for the highly selective removal and preconcentration of U(VI) ions from aqueous solutions in environmental pollution management.

Asymmetric supercapacitor based on graphene oxide/polypyrrole composite and activated carbon electrodes

Graphene oxide/polypyrrole (GO/PPy) composite is synthesized by in situ oxidation polymerization of pyrrole (Py) in the presence of GO and used for supercapacitor electrode. The scanning electron microscope (SEM) observes that PPy nanoparticles are uniformly grown on the surfaces of GO sheets, leading to increase both the specific surface area and the electrical conductivity of material. GO/PPy composite exhibits better electrochemical performances than the pure individual components. When the mass ratio of GO to Py is 10:100, the GO/PPy composite electrode shows the highest capacitance of 332.6 F g−1, and presents high rate capability. An asymmetric supercapacitor is fabricated by using the optimized GO/PPy composite as positive electrode and activated carbon (AC) as negative electrode. The asymmetric supercapacitor can be cycled reversibly in the voltage range of 0–1.6V, and exhibits the maximum energy density of 21.4 Wh kg−1 at a power density of 453.9Wkg−1. Furthermore, the GO/PPy//AC asymmetric supercapacitor displays good rate capability and excellent cyclic durability.

Enhanced electromagnetic absorption properties of reduced graphene oxide–polypyrrole with NiFe2O4 particles prepared with simple hydrothermal method

The ternary composites of reduced graphene oxide–polypyrrole–NiFe2O4 (RGO–PPy–NiFe2O4) were synthesized via a two-step method and the electromagnetic absorption properties were investigated. The average diameter of NiFe2O4 particles on RGO–PPy ranged from 10 to 20nm. The results revealed that the electromagnetic absorption properties and the absorption bandwidth of RGO–PPy–NiFe2O4 are much better than RGO–PPy. The maximum reflection loss of RGO–PPy–NiFe2O4 is −44.7dB at 14.9GHz and the absorption bandwidth with the reflection loss below −10dB is 4.7GHz with a thickness of 1.75mm. Furthermore, our strategy provides a feasible method to obtain the ternary composites with excellent electromagnetic absorption properties and wide absorption bandwidth for future investigators.

High performance nitrogen-doped porous graphene/carbon frameworks for supercapacitors

Nitrogen-doped porous graphene/carbon (NPGC) framework electrode materials have been synthesized via chemical activation of graphene oxide/polypyrrole (GOP) composites with KOH. The effects of the mass ratio of KOH/GOP and activation temperature on the electrochemical performance of NPGC have been discussed. It is found that the NPGC prepared by activating GOP (GO : Py = 1 : 40) with 3.5 times mass of KOH at 650 °C (NPGC650) exhibits the highest specific capacitance of 405 F g−1 at a current density of 0.2 A g−1. Particularly, the specific capacitance still remains at 249 F g−1 even at a current density as high as 10 A g−1. Moreover, 96% of the capacitance can be retained after 1000 cycles even under a high operation current of 10 A g−1. The present work provides a novel strategy to synthesize NGPC electrode material for supercapacitors.

Reduced Graphene Oxide-Polypyrrole Composite as a Catalyst for Oxygen Electrode of High Rate Rechargeable Li-O2 Cells

Polypyrrole (PPY) is grown on reduced graphene oxide (RGO) and the composite is studied as a catalyst for O2 electrode in Li-O2 cells. PPY is uniformly distributed on the two dimensional RGO layers. Li-O2 cells assembled in a non-aqueous electrolyte using RGO-PPY catalyst exhibit an initial discharge capacity as high as 3358 mAh g−1 (3.94 mAh cm−2) at a current density of 0.3 mA cm−2. The voltage gap between the charge and discharge curves is less for Li-O2(RGO-PPY) cell in comparison with Li-O2(RGO) cell. The Li-O2(RGO-PPY) cell delivers a discharge capacity of 550 mAh g−1 (0.43 mAh cm−2) at a current density of 1.0 mA cm−2. The results suggest that RGO-PPY is a promising catalyst of O2 electrode for high rate rechargeable Li-O2 cells.