Graphene Polypyrrole Research Articles

Detecting low-concentration ammonia with a surface acoustic wave sensor using a silver nanoparticles–graphene–polypyrrole hybrid nanocomposite film

In this study, a surface acoustic wave (SAW) resonator coated with graphene/polypyrrole hybrid nanocomposite films decorated with silver nanoparticles (AgNPs-G/PPy) is proposed for detecting ammonia (NH3) in parts-per-billion concentrations. The AgNPs-G/PPy hybrid nanocomposite film was synthesized via in situ chemical oxidative polymerization. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction were used to characterize the AgNPs-G/PPy hybrid nanocomposite film, confirming its successful synthesis and identifying a wrinkled multilayered structure. The AgNPs-G/PPy hybrid nanocomposite film was spin-coated onto the surface of a stress-compensated temperature-cut quartz SAW resonator having an operating frequency of 98.5 MHz to create an NH3 gas sensor. NH3 adsorption by the AgNPs-G/PPy hybrid nanocomposite film modulated the acoustic wave velocity, and the corresponding frequency shift served as a sensing signal. The synergistic interaction between the three constituent materials (AgNPs, graphene, and polypyrrole) enhanced the sensitivity, selectivity, and response speed of the sensor for NH3 detection. At room temperature, the proposed sensor exhibited a positive frequency shift of 568 Hz when exposed to 50 ppb of NH3 gas and a rapid response time of less than 60 s. In addition, the SAW sensor exhibited excellent selectivity.

Optimization of graphene polypyrrole for enhanced adsorption of moxifloxacin antibiotic: an experimental design approach and isotherm investigation

The presence of antibiotics in water systems had raised a concern about their potential harm to the aquatic environment and human health as well as the possible development of antibiotic resistance. Herein, this study investigates the power of adsorption using graphene-polypyrrole (GRP-PPY) nanoparticles as a promising approach for the removal of Moxifloxacin HCl (MXF) as a model antibiotic drug. GRP-PPY nanoparticles synthesis was performed with a simple and profitable method, leading to the formation of high surface area particles with excellent adsorption properties. Characterization was assessed with various techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). Box-Behnken experimental design was developed to optimize the adsorption process. Critical parameters such as initial antibiotic concentration, nanoparticle concentration, and pH were investigated. The Freundlich isotherm model provided a good fit to the experimental data, indicating multilayer adsorption of MXF onto the GRP-PPY-NP. As a result, a high adsorption capacity of MXF (92%) was obtained in an optimum condition of preparing 30 μg/mL of the drug to be adsorbed by 1 mg/mL of GRP-PPY-NP in pH 9 within 1 h in a room temperature. Moreover, the regeneration and reusability of GRP-PPY-NP were investigated. They could be effectively regenerated for 3 cycles using appropriate desorption agents without significant loss in adsorption capacity. Overall, this study highlights the power of GRP-PPY-NP as a highly efficient adsorbent for the removal of MXF from wastewater as it is the first time to use this NP for a pharmaceutical product which shows the study's novelty, and the findings provide valuable insights into the development of sustainable and effective wastewater treatment technologies for combating antibiotic contamination in aquatic environments.

Wet Synthesis of Graphene-Polypyrrole Nanocomposites via Graphite Intercalation Compounds

Graphene-polypyrrole (GP) nanocomposites were synthesized by a wet-way protocol using a graphite bisulfate (GBS) precursor. Consequently, GBS, a type of graphite intercalation compound, was prepared in the presence of concentrated sulfuric acid in the presence of a potassium periodate oxidizer. Three different types of graphite precursor with particle sizes of <50 μm, ≥150, ≤830 μm, and ≤2000 μm were used for this purpose. It was found that in the Raman spectra of GBS samples, the characteristic D band, which is caused by defects in the graphene layer, disappears. Therefore, the proposed synthesis protocol of GBS could be considered as a prospective intermediate stage in the preparation of graphene with low defect concentration. In contrast to alkali metal intercalation, the intercalation process involving anions with a relatively complex structure (e.g., HSO4−), which has been much less studied and requires further research. On the basis of the results obtained, structural models of graphite intercalation compounds as well as GP nanocomposites were discussed. The most relevant areas of application for GP nanocomposites, including energy storage and (bio)sensing, were considered. This work contributes to the development of cost-effective, scalable, and highly efficient intercalation methods, which still remain a significant challenge.

Flexible and weavable 3D porous graphene/PPy/lignocellulose-based versatile fibrous wearables for thermal management and strain sensing

Fibrous wearable electronics have attracted extensive attention owing to their lightness and flexibility. However, they face challenges to work synergically with conductive components when stable performance and multifunction are required simultaneously. Here, plant-extracted 3D porous Juncus effusus (JE) fiber decorated with conductive graphene/polypyrrole (G-PPy) yields flexible smart fibers (G-PPy-JE) with integration of Joule heating and strain sensing properties. G-PPy-JE fibers were prepared by hierarchically anchoring the graphene sheets and PPy to 3D JE microfibrils via a facile dip coating and in-situ polymerization method. Synergistic effects in the hybrid architecture contribute to a highest conductivity of G-PPy-JE (96.85 S m−1) compared to pristine JE, G-JE, and PPy-JE. On the one hand, G-PPy-JE fibers showed a great electric-thermal property, which achieved a temperature of 147 °C at 10 V within 10 s. The good Joule heating performance maintained when weaving these fibers into fabrics as thermal therapy clothing. On the other hand, G-PPy-JE fibers after encapsulation can serve as a strain sensor with a high sensitivity (GF of 7.36–11.36), great stability (10–100 %), and good durability over 500 cycles. The strain sensor also reflected capabilities to detect a full range of human motions. This work paves a way for manufacturing cost-effective, green, and versatile fibrous electronics for promising wearable application.

Highly efficient removal of Pb2+ and Cu2+ ions using r-GO/PPY/SiO2 based nanosorbent

ABSTRACT In the treatment of wastewater incorporating inorganic and organic contaminants, graphene oxide and polymer-based nanocomposites have gained a lot of interest. In the current study, reduced graphene oxide (r-GO), polypyrrole (PPY) and silica (SiO2) based nanocomposite material (r-GO/PPY/SiO2) was utilised as an effective adsorbent for the removal of Pb2+ and Cu2+ ions from contaminated water. The r-GO/PPY/SiO2 was synthesised using an efficient and low-cost approach, and it was then analysed using various techniques. Under the employed adsorption conditions, this material was demonstrated to be a very efficient adsorbent for the decontamination of Pb2+ and Cu2+ ions in wastewater. The highest adsorption capacities of r-GO/PPY/SiO2 for Pb2+ and Cu2+ ions were evaluated to be 19.305 and 23.148 mg/g. The pseudo-second order rate constants have been determined as 90.9 and 66.225 mg/g/min for Pb2+ and Cu2+ ions, respectively.

Polyoxomolybdate–Polypyrrole–Graphene Oxide Nanohybrid Electrode for High-Power Symmetric Supercapacitors

Supercapacitors have emerged as one of the most promising candidates for high-performance, safe, clean, and economical routes to store and release of nonfossil energy. Designing hybrid materials by...

Carbon monoxide sensor based on polypyrrole–graphene oxide composite: a cost-effective approach

Carbon monoxide sensor based on polypyrrole–graphene oxide composite: a cost-effective approach

Conductive Polymer (Graphene/PPy)-BiPO4 Composite Applications in Humidity Sensors.

In this particular experiment, a chain of conductive polymer graphene/polypyrrole (Gr/PPy) and BiPO4—or (Gr/PPy)–BiPO4—materials were prepared and used as moisture-sensitive materials. The structure and morphology of the conductive polymer (Gr/PPy)–BiPO4 materials were analyzed using an X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Moreover, properties such as hysteresis loop, impedance, sensing response, and response and recovery time were calculated and evaluated using an inductance–capacitance–resistance analyzer. The data expressed that PPy/BiPO4, as prepared in this study, exhibited excellent sensing properties, with impedance changing by only a few orders of range. Furthermore, the response time and time of recovery were 340 s and 60 s, respectively, and negligible humidity hysteresis occurred at different relative humidities. Therefore, conductive PPy/BiPO4, as prepared in the present study, is an excellent candidate for application in humidity sensors.

Computational Study of Graphene–Polypyrrole Composite Electrical Conductivity

In this study, the electrical properties of graphene–polypyrrole (graphene-PPy) nanocomposites were thoroughly investigated. A numerical model, based on the Simmons and McCullough equations, in conjunction with the Monte Carlo simulation approach, was developed and used to analyze the effects of the thickness of the PPy, aspect ratio diameter of graphene nanorods, and graphene intrinsic conductivity on the transport of electrons in graphene–PPy–graphene regions. The tunneling resistance is a critical factor determining the transport of electrons in composite devices. The junction capacitance of the composite was predicted. A composite with a large insulation thickness led to a poor electrochemical electrode. The dependence of the electrical conductivity of the composite on the volume fraction of the filler was studied. The results of the developed model are consistent with the percolation theory and measurement results reported in literature. The formulations presented in this study can be used for optimization, prediction, and design of polymer composite electrical properties.

Electronic structure of polypyrrole composited with a low percentage of graphene nanofiller.

The low concentration of graphene (<5%) in graphene/polypyrrole composites makes it quite challenging to devise a theoretical model for these composites. Thus, herein, we present theoretical calculations to determine the geometric electronic and optical properties of graphene/polypyrrole composites. Ribbon and sheet models of various sizes were considered for graphene. Oligopyrrole of various lengths was deposited in the graphene model in different orientations including π-stacking, tilted and vertical orientations. Theoretical calculations at the M062X/def2-SVP level revealed that π-stacking is the preferred orientation. To model a lower concentration of graphene, sandwich complexes of oligopyrrole were considered with graphene nanoribbons. Interaction energies revealed that sandwich complexes possessed superior additivity. The NCI analysis established that weak van der Waals interactions existed in all composites. Moreover, the HOMO-LUMO gap decreases as the concentration of graphene increases. Thus, the computed optical band gap of the C58H24-based composite is about 1.7 eV, which is consistent with the reported experimental value (2.1-1.81 eV). The computed band gap further decreases to ∼1.6 eV when the proportion of graphene increases to C64H26. Thus, our results for the graphene nanoribbon-based polypyrrole composites are in good agreement with experimental results. The UV/visible spectra revealed that as the concentration of graphene increases, a red shift is observed for all the configurations, which is consistent with experimental results.

Polymer-Assisted Electrophoretic Synthesis of N-Doped Graphene-Polypyrrole Demonstrating Oxygen Reduction with Excellent Methanol Crossover Impact and Durability.

The design and synthesis of metal-free catalysts with superior electrocatalytic activity, high durability, low cost, and under mild conditions is extremely desirable but remains challenging. To address this problem, a polymer-assisted electrochemical exfoliation technique of graphite in the presence of an aqueous acidic medium is reported. This simple, cost-effective, and mass-scale production approach could open the possibility for the synthesis of high-quality nitrogen-doped graphene-polypyrrole (NG-PPy). The NG-PPy catalyst displays an improved half wave potential (E1/2 =0.77 V) in alkaline medium compared with G-PPy (E1/2 =0.66 V). Most importantly, this catalyst demonstrates excellent stability with high methanol tolerance, and it outperforms the commercial Pt/C catalyst and other previously reported metal-free catalysts. The content of graphitic nitrogen atoms is the key factor for the enhancement of electrocatalytic activity towards oxygen reduction reactions (ORR). Interestingly, the NG-PPy catalyst can be used as a cathode material in a zinc-air battery, which demonstrates a higher peak power density (59 mW cm-2 ) than G-PPy (36.6 mW cm-2 ), highlighting the importance of the low-cost material synthesis approach towards the development of metal-free efficient ORR catalysts for fuel cell and metal-air battery applications. Remarkably, the polymer-assisted electrophoretic exfoliation of graphite with a high yield (≈88 wt %) of few-layer graphene flakes could pave the way towards the mass production of high-quality graphene for a variety of applications.

Fabrication of polyaniline–carrot derived carbon dots/polypyrrole–graphene nanocomposite for wide potential window supercapacitor

In recent years, special attention of energy researchers has been paid to application of polymer–carbon dots composite in energy storage systems. In this work, for the first time, we introduced a combination of polyaniline, carbon dots, polypyrrole and graphene as high performance supercapacitor. Synergistic effect of conductive polymers combined with specific properties of graphene and carbon dots improved the electrochemical performance of supercapacitor. Carbon dots was prepared from carrot juice hydrothermally as a biomass carbon source and polyaniline–carbon dots was synthesized via in-situ polymerization. Electrochemical performance of polyaniline with different carbon dots content was investigated and nanocomposite of polyaniline with 10 wt% carbon dots was selected to mix with polypyrrole–graphene to obtain a high potential window supercapacitor. The as-prepared composite was characterized by several spectroscopic and microscopic techniques. The electrochemical properties of this electrode were studied by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy techniques. A polyaniline–carbon dots (10%)/polypyrrole–graphene has showed the maximum specific capacitance of 396 F g−1. Value of specific capacity remained at 62% under the current density of 5 A g−1.

Effects of synergism and multistep heating in graphene–polypyrrole–polymethyl methacrylate composites on their electrical and mechanical properties in additive manufacturing

Effects of synergism and multistep heating in graphene–polypyrrole–polymethyl methacrylate composites on their electrical and mechanical properties in additive manufacturing

A Two‐Dimensional Mesoporous Polypyrrole–Graphene Oxide Heterostructure as a Dual‐Functional Ion Redistributor for Dendrite‐Free Lithium Metal Anodes

AbstractGuiding the lithium ion (Li‐ion) transport for homogeneous, dispersive distribution is crucial for dendrite‐free Li anodes with high current density and long‐term cyclability, but remains challenging for the unavailable well‐designed nanostructures. Herein, we propose a two‐dimensional (2D) heterostructure composed of defective graphene oxide (GO) clipped on mesoporous polypyrrole (mPPy) as a dual‐functional Li‐ion redistributor to regulate the stepwise Li‐ion distribution and Li deposition for extremely stable, dendrite‐free Li anodes. Owing to the synergy between the Li‐ion transport nanochannels of mPPy and the Li‐ion nanosieves of defective GO, the 2D mPPy‐GO heterostructure achieves ultralong cycling stability (1000 cycles), even tests at 0 and 50 °C, and an ultralow overpotential of 70 mV at a high current density of 10.0 mA cm−2, outperforming most reported Li anodes. Furthermore, mPPy‐GO‐Li/LiCoO2 full batteries demonstrate remarkably enhanced performance with a capacity retention of &gt;90 % after 450 cycles. Therefore, this work opens many opportunities for creating 2D heterostructures for high‐energy‐density Li metal batteries.

A Two-Dimensional Mesoporous Polypyrrole-Graphene Oxide Heterostructure as a Dual-Functional Ion Redistributor for Dendrite-Free Lithium Metal Anodes.

Guiding the lithium ion (Li-ion) transport for homogeneous, dispersive distribution is crucial for dendrite-free Li anodes with high current density and long-term cyclability, but remains challenging for the unavailable well-designed nanostructures. Herein, we propose a two-dimensional (2D) heterostructure composed of defective graphene oxide (GO) clipped on mesoporous polypyrrole (mPPy) as a dual-functional Li-ion redistributor to regulate the stepwise Li-ion distribution and Li deposition for extremely stable, dendrite-free Li anodes. Owing to the synergy between the Li-ion transport nanochannels of mPPy and the Li-ion nanosieves of defective GO, the 2D mPPy-GO heterostructure achieves ultralong cycling stability (1000 cycles), even tests at 0 and 50 °C, and an ultralow overpotential of 70 mV at a high current density of 10.0 mA cm-2 , outperforming most reported Li anodes. Furthermore, mPPy-GO-Li/LiCoO2 full batteries demonstrate remarkably enhanced performance with a capacity retention of >90 % after 450 cycles. Therefore, this work opens many opportunities for creating 2D heterostructures for high-energy-density Li metal batteries.

Polypyrrole doped graphene oxide reinforced epoxy nanocomposite with advanced properties for coatings of mild steel

In this paper epoxy coatings containing Polypyrrole–Graphene Oxide (PPy–GOs) hybrid nanocomposites with various weight fraction (0.5, 1 and 2 wt%) were prepared to investigate the effect of PPy-GO on the enhancement of anti-corrosion properties in epoxy based nanocomposite coatings on mild steel. PPy–GOs hybrids, PPy and GO were characterized by FT-IR, XRD, SEM and TEM analysis and their effect on the anticorrosion performance of the composite coatings, the epoxy (E), epoxy mixed with PPy-GO (EPGs), PPy (EP) and physically mixture of PPy and GO (EP + G) coatings were studied by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and Open Circuit Potential (OCP). The results demonstrated that the dispersion of PPy-GO hybrids in the epoxy coatings improved corrosion performance of coating compared to the other coatings and maximum corrosion resistance is achieved via adding 0.5 wt.% PPy-GO. This behavior related to the better dispersion and interaction between PPy-GOs hybrids and epoxy matrix compared to other fillers.

Preparation of Graphene–Polypyrrole Hollow Sphere by Pickering Emulsion Method and Their Electrochemical Performances as Supercapacitor Electrode

Graphene–polypyrrole hollow sphere composite was synthesized for the first time via Pickering emulsion polymerization using graphene oxide as Pickering stabilizer. It was found that polypyrrole and graphene were well hybrid and all graphene–polypyrrole composites had a uniform hollow sphere structure, whose diameters gradually decreased as the pyrrole content decreased. The electrochemical properties of the composites as supercapacitor electrode were investigated. The test results displayed that the specific capacitance of the optimal ratio of composite could reach 238[Formula: see text]F/g at a current density of 1[Formula: see text]A/g, and a 90.7% capacitance retention could be achieved after 1500 cycles, which was a significant improvement compared with the 62.2% retention of pure polypyrrole.

Deciphering the Impact of Surface Defects and Functionalization on the Binding Strength and Electronic Properties of Graphene–Polypyrrole Nanocomposites: A First-Principles Approach

The distinct effectiveness of graphene-based nanostructures, including pristine graphene, graphene with Stone–Wales defects, graphene oxides, and multilayered graphene materials, toward the develop...

Reduced graphene oxide/polypyrrole/nitrate reductase deposited glassy carbon electrode (GCE/RGO/PPy/NR): biosensor for the detection of nitrate in wastewater

In the present work, a novel biosensor (GCE/RGO/PPy/NR) based on the nanocomposite of reduced graphene oxide (RGO), polypyrrole (PPy) immobilized by nitrate reductase (NR) was developed on a glassy carbon electrode (GCE). The conductive nanocomposite (RGO/PPy) was synthesized by in situ oxidative polymerization of pyrrole in the presence of RGO in acidic medium. A facile and green path was employed to synthesize RGO from graphene oxide (GO). This was performed by a novel route using Abelmoschus esculentus vegetable extract as a stabilizing and reducing agent for GO. The composite of reduced graphene oxide and polypyrrole (RGO/PPy) was deposited onto GCE with subsequent deposition of NR enzyme on the GCE/RGO/PPy to develop GCE/RGO/PPy/NR biosensor. The surface morphology and structural features of the composites were studied by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical behavior and electrocatalytic activity of the biosensor were examined by cyclic voltammetry at different scan rates (20–100 mV s−1) in the synthetic nitrate solution. The developed bio-anode achieved a maximum current density of 4.24 mA cm−2 at a scan rate of 100 mV s−1 for 10 mM sodium nitrate solution.

A ternary nanocomposites of graphene / TiO2 / polypyrrole for energy storage applications

ABSTRACTDesigning a new electrode active materials including graphene and nanomaterials such as Titanium dioxide (TiO2) with polypyrrole have important for supercapacitor devices. In this work, we present a new ternary nanocomposite for using reduced graphene oxide (rGO), TiO2 and polypyrrole (rGO/TiO2/PPy) for supercapacitors. rGO/TiO2/PPy nanocomposites were characterized by the analysis of Fourier transform infrared-attenuated transmission reflectance (FTIR-ATR), Raman spectroscopy, and scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX). Electrochemical tests were taken by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies. We have obtained the highest specific capacitance of Csp = 431.23 F/g for [rGO]o/[Py]o = 1/1 at 10 mV/s. A ternary rGO/TiO2/PPy nanocomposite has higher Csp values than Csp = 122.12 F/g at 10 mV/s for rGO/PPy, Csp = 93.17 F/g at 4 mV/s for rGO and Csp = 45.16 F/g at 4 mV/s for GO.A high energy density was obtained as E = 2.03 Wh/kg and power density of P = 18.3 kW/kg for rGO/TiO2/PPy nanocomposite at 1000 mV/s. rGO/TiO2/PPy nanocomposite had a relatively high Coulombic efficiency, as well as a retention of ∼100% of its original capacitance for [rGO]o/[Py]o = 1/1 after 1000 cycles. A novel synthesized rGO/TiO2/PPy nanocomposite may be used for supercapacitor devices due to its good electrochemical performances.