Graphene Oxide Polypyrrole Research Articles

Sensing of volatile pollutants on reduced graphene oxide-polypyrrole composite: DFT investigation.

Air pollutants generated from volatile toxic chemicals pose significant public health concerns. Density functional theory (DFT) computations were used in this research to explore the efficiency and mechanism of harmful gas sensing over the reduced graphene oxide-polypyrrole (rGO-PPy) composite. Volatile molecule sensing was investigated for the NH3, H2CO, CH3OH, and C2H5OH gas molecules over three PPy orientations on the rGO substrate. Results showed that PPy orientation over rGO plays a crucial role in the sensing efficiency of the investigated gas molecules. The rGO-PPy composite, with PPy in a vertical orientation, demonstrated higher stability and enhanced sensing than other orientations. The results indicate that the strong hydrogen bonding of NH3 and CH3OH with both PPy and rGO significantly enhanced the sensing of these gas molecules on rGO by influencing the charge transfer with adsorption energy values of - 0.84 and - 0.92 eV, respectively. The lack of a direct hydrogen bonding with rGO and the weak hydrogen bonding with PPy caused a weak adsorption of H2CO and C2H5OH over rGO as indicated by the adsorption energy values of - 0.60 and - 0.78 eV, respectively. Selectivity analysis for the NH3 and C2H5OH gas molecules showed that NH3 can maintain hydrogen bonding with PPy in the presence of C2H5OH while C2H5OH cannot sustain this interaction. This study highlights the importance of the structural and electronic properties of the rGO-PPy composite in volatile pollutant sensing, providing insights for designing high-performance gas sensors.

Fractal-like kinetic modelling for sorption of diclofenac onto graphene oxide/polypyrrole composite: Mechanism analysis and response surface methodology for optimization

Graphene oxide/polypyrrole (GO/PPy) composite material was prepared to explore its utility in the removal of diclofenac from aqueous system. The characterization was achieved using Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, thermogravimetry-differential thermal analyses, scanning electron microscopy coupled with energy dispersive X-ray analysis and transmission electron microscopy analysis. Response surface methodology was exploited to optimize the process variables for the sorption of diclofenac onto GO/PPy. Three variables such as contact time, adsorbent dose and initial concentration of diclofenac were selected for optimization to achieve maximum removal of diclofenac. All experiments were conducted at pH 5. The contact time, adsorbent dose and initial concentration of diclofenac were examined in the ranges of 03–37 min, 13–147 mg/25 mL and 10–110 mg/L, respectively. The optimum values obtained were: contact time: 20 min; GO/PPy dose: 80 mg/25 mL and initial diclofenac concentration: 60 mg/L. The maximum sorption capacity and percent removal of diclofenac were found to be 29.50 mg/g and 98.50 %, respectively. The measured data (at equilibrium) were investigated using different isotherm models and best described by Freundlich model (R2 = 0.9943–0.9952, χ2 = 0.0062–0.0077, APE = 1.45–1.61). The experimental kinetic data were analyzed with the help of fractal-like kinetic models. The kinetic data are best fitted by fractal-like mixed 1,2 order (R2 = 0.9830–0.9886, χ2 = 0.0014–0.0036, APE = 0.6780–1.1059). Adsorption mechanism has been discussed based on kinetic, FTIR and molecular docking studies which indicated the participation of π-π interactions and hydrogen bonding on energetically heterogeneous surface. The adsorption/desorption test demonstrated that GO/PPy had excellent reusability performance up to 15 cycles.

One step electrode fabrication of thin film graphene oxide-polypyrrole composite by electrodeposition using cyclic voltammetry for hybrid type supercapacitor application

One step electrode fabrication of thin film graphene oxide-polypyrrole composite by electrodeposition using cyclic voltammetry for hybrid type supercapacitor application

Styrene-based ternary composite elastomers functionalized with graphene oxide-polypyrrole under iron(III)-alkyl benzenesulfonate oxidants for supercapacitor integrated strain sensor system

In this study, we demonstrated a supercapacitor-integrated strain sensor system using three types of iron(III)-alkylbenzenesulfonate-based oxidizing agents, so as to induce surface-treated SEBS-rGO-PPy composite films. PPy has incorporated into the SEBS-rGO film under oxidizing agent treatment by VPP. The electromechanical properties, chemical compositions, supercapacitor, and strain sensor durability performances of the composite films were examined. The composite A2 iron(III)-(4-ethylbenzenesulfonic acid surface-treated SEBS-rGO-PPy films exhibited better performance than the other two A0 (benzene sulfonic acid)-and A1 (p-toluene sulfonic acid)-based oxidants, in terms of strain sensor integrate energy storage concerts. These types of systems have good capacity retention ~95% over 5000 charge-discharge cycles. The biocompatibility studies exhibited good results for the three composites. The high-flexibility supercapacitor combined with the sensor system has the potential to be used as an energy storage system for smart electronic wearable skin-based devices.

An ultrasensitive electrochemical immunosensor for hepatitis C antibodies based on one-step-eletrosynthetized polypyrrole-graphene nanocomposite.

An ultrasensitive label-free electrochemical immunosensor was developed for hepatitis C antibodies (anti-HCV). Worldwide, it is estimated 71 million people have HCV infection in a chronic stage that may lead to cirrose and cancer. To achieve HCV elimination, health programs should include screening testing based on anti-HCV detection allowing the early-stage treatment. The immunosensor was based on a graphene oxide-polypyrrole (PPy–GO) film one-step electropolymerized on the electrode surface. Ultrasensitive anti-HCV detection was ensured by HCV antigen conjugated to biotin that was immobilized in a great amount on streptavidin-coated nanostructured surface. Analytical responses were obtained by anodic peaks from the square wave voltammetry in the presence of ferrocyanide/ferricyanide as a redox probe. This immunosensor exhibited a linear range from 2 to 14 ng mL−1 of anti-HCV and a limit of detection in the clinical range (1.63 ng mL−1). Furthermore, the immunosensor presented an efficient performance for the determination of anti-HCV in spiked serum samples, becoming this developed nanosensor as potential tools for early HCV diagnosis and screening.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10853-022-06992-5.

Reduced Graphene Oxide-Polypyrrole Aerogel-Based Coaxial Heterogeneous Microfiber Enables Ultrasensitive Pressure Monitoring of Living Organisms.

Pressure sensors for living organisms can monitor both the movement behavior of the organism and pressure changes of the organ, and they have vast perspectives for the health management information platform and disease diagnostics/treatment through the micropressure changes of organs. Although pressure sensors have been widely integrated with e-skin or other wearable systems for health monitoring, they have not been approved for comprehensive surveillance and monitoring of living organisms due to their unsatisfied sensing performance. To solve the problem, here, we introduce a novel structural design strategy to manufacture reduced graphene oxide-polypyrrole aerogel-based microfibers with a typical coaxial heterogeneous structure, which significantly enhances the sensitivity, resolution, and stability of the derived pressure microsensors. The as-fabricated pressure microsensors exhibit ultrahigh sensitivities of 12.84, 18.27, and 4.46 kPa-1 in the pressure ranges of 0-20, 20-40, and 40-65 Pa, respectively, high resolution (0.2 Pa), and good stability in 450 cycles. Furthermore, the microsensor is applied to detect the movement behavior and organic micropressure changes for mice and serves as a platform for monitoring micropressure for the integrative diagnosis both in vivo and in vitro of organisms.

Capacitive Aptasensor for 17β-Estradiol Detection in a Non-Faradaic Electrochemical System Based on NH <sub>2</sub>-GO/PPy

17s-estradiol (E2) is an endocrine-disrupting chemical (EDC) being a hot debate topic that has been discussed among researchers for a decade due to its unexpected harmful effects on humans and wildlife. In this study, we report facile methods to fabricated label-free aptasensor based on the non-faradic mode by using amine-functionalized graphene oxide polypyrrole (NH2-GO/PPy) modified gold interdigitated electrode (IDE) for direct capacitive detection of 17β-estradiol. The as-prepared NH2-GO/PPy nanocomposites have been successfully characterized by FESEM, AFM, FTIR, and electrochemical impedance spectroscopy (EIS). The results show that NH2-GO/PPy/IDE was able to increase the capacitive current as opposed to bare gold IDE. While E2 binding was detected by a decrease in the electrode capacitance due to aptamer's conformational change towards E2. In addition, the biosensor showed a dynamic range of detection from 100nM to 1 pM with a low detection limit of about 0.13 pM. The recoveries result also presented in this paper were validated using HPLC exhibited high sensitivity for BPA detection and were successfully applied to detect E2 in real samples with good recoveries.

A Novel Electrochemical DNA Biosensor Based on a Gold Nanoparticles-Reduced Graphene Oxide-Polypyrrole Nanocomposite to Detect Human T-Lymphotropic Virus-1

An electrochemical DNA biosensor for the Human T-Lymphotropic Virus-1 (HTLV-1) detection was developed using differential pulse voltammetry (DPV). For this purpose, single-strand DNA (ssDNA) probe was immobilized on the screen-printed carbon electrode (SPCE) modified with nanocomposite of reduced graphene oxide, polypyrrole, and gold nanoparticles (rGO-PPy-AuNPs). Then, the hybridization with the target DNA was studied by measuring the electrochemical oxidation response of the anthraquinone-2-sulfonic acid sodium salt monohydrate (AQMS). The calibration curve displayed a linear range between $10^{-15}$ and $10^{-7}$ mol/L, with a detection limit of 40 atto-molar towards HTLV-1 DNA concentrations. This DNA sensing platform was successfully applied to detect the DNA extracted from Peripheral Blood Mononuclear Cells (PBMC) sample. Also, the specificity of the proposed biosensor was investigated by a positive sample of HTLV-1, a positive sample of HSV-1 (non-complementary sample), a mix-sample (HTLV-1 and HSV-1) and negative sample. Moreover, the relative standard deviation (RSD) of repeatability and reproducibility tests was 2.8 % and 4.3 % respectively, that it is less than 20% and demonstrates the good reusability and stability of the proposed biosensor.

Graphene Oxide-Polypyrrole Coating for Functional Ceramics.

Ceramic substrates were metallized with a Ni-Mo-P electroless coating and further modified with a polypyrrole (PPy) coating by the electrodeposition method. The properties of the polypyrrole coating were studied with the addition of a graphene oxide (GO) nanomaterial prior to the electrodeposition and its reduction degree. Fourier Transform Infrared Spectroscopy, Field-Emission Scanning Electron Microscopy, Raman spectroscopy and cyclic voltammetry were employed to characterize the properties of the coatings. The results indicated the successful synthesis of conductive electrodes by the proposed approach. The electrodeposition of PPy and its charge storage properties are improved by chemically reduced GO. The surface capacitive contribution to the total stored charge was found to be dominant and increased 2–3 fold with the reduction of GO. The chemically reduced GO-modified PPy exhibits the highest capacitance of 660 F g−1 at 2 mV s−1, and shows a good cyclability of 94% after 500 charge/discharge cycles. The enclosed results indicate the use of an NiMoP electroless coating, and modification with a carbon nanomaterial and conducting polymer is a viable approach for achieving functional ceramics.

Fabrication of poly(vinyl alcohol)–graphene oxide–polypyrrole composite hydrogel for elastic supercapacitors

High-performance elastic supercapacitors represent a promising kind of energy storage devices that can be employed in soft robotics and wearable electronics. The development of novel functional materials as supercapacitor electrode is still tremendously challenging. In the present work, the conductive polyvinyl alcohol–graphene oxide–polypyrrole (PVA–GO–PPy) composite hydrogels are fabricated through in situ polymerization of pyrrole in the presence of PVA and GO and subsequent freeze-thawing. Owing to the unique porous layered-wrinkle network and functional component of PVA–GO–PPy composite hydrogels, the as-prepared hydrogels exhibit lightweight, elasticity, compressibility, formability and softness. Furthermore, the mechanically robust and microstructured PVA–GO–PPy composite hydrogels are used to construct an elastic symmetric solid-state supercapacitor with good electrochemical performance. The device exhibits long-term compression/recovery elasticity under 50% strain, and even the volumetric capacitance retention is still about 81% when the strain is up to 80%. The excellent compression/recovery elasticity and good mechanical integrity of the high-performance supercapacitor based on PVA–GO–PPy composite hydrogel open up new opportunities for next-generation electronic devices in the practical application.

Double coating of graphene oxide–polypyrrole on silk fibroin scaffolds for neural tissue engineering

The desired scaffolds for neural tissue engineering need to have electrical conductivity. In this study, we doubly coated graphene oxide and polypyrrole on silk fibroin scaffolds (SF@GO-PPY) by a facile method to improve its electrical conductivity. The graphene oxide–polypyrrole double coating was distributed homogeneously on silk fibroin scaffolds. Compared with silk fibroin scaffolds, the SF@GO-PPY scaffold showed higher electrical conductivity, electrochemical property, mechanical property, and thermal stability. The π–π stacking interaction between polypyrrole and graphene oxide might contribute to the superior conductive and electrochemical property of the SF@GO-PPY scaffold. Moreover, in vitro cell experiment carried out on SH-SY5Y cells showed no cytotoxicity of all the scaffolds. Thus, the results indicated that the SF@GO-PPY scaffold might be a suitable candidate for the application in neural regeneration field.

Synthesis and Characterization of Gamma Irradiated Graphene Oxide-Polypyrrole Nanocomposites

Variations in crystalline structure, optical property, structural bonding in Graphene Oxide (GO) doped polypyrrole (PPy) under gamma irradiation at 100 KGy with effective dose rate of 2.86 KGy per hour have been studied. The crystalline structure has been studied utilizing XRD spectroscopy and it has become clear that as compare to non-irradiated, irradiated sample show more shift toward crystalline nature, this is because of the decrease in d -spacing. The variation in optical properties have been evaluated using UV-VIS spectroscopy, it has been pointed that gamma irradiation reduces the optical band gap due to the chemical reactions, such as chain scissioning etc., induced by gamma exposure, this result is further supported by FT-IR spectroscopy.

The polymeric conformational effect on capacitive deionization performance of graphene oxide/polypyrrole composite electrode

Exploitation of novel faradic materials is an alternative implementation for solving the problem of poor specific electrosorption capacity that conventional carbon materials are encountered in capacitive deionization. Particularly, composite electrode is just a suitable choice because of its potentially high ion-storage ability. Herein, a cyclic voltammetric treatment method with different low limit of potential window was used to manipulate the polymeric conformation and doping level of graphene oxide/polypyrrole (GO/PPy) composite electrode. Based on it, the effect of polymeric structure on the electrosorption performance was systematically studied. When the low limit of potential window is shifted negatively enough, the irreversible polymeric conformational shrinks of GO/PPy are promoted, which not only hinders the insertion process of ions, but also decreases the doping level of polymer due to the intensive interchain-action produced by more entangled polymeric chain. Thus, the number of intercalated ions should decrease, which is expressed by electrochemical impedance spectroscopy (EIS) results and is proportional to the electrosorption capacity of GO/PPy composite electrode in membrane capacitive deionization (MCDI) process. Our work suggests that the less packing density, higher doping level and more charge delocalization on PPy backbone in electrode are beneficial to enhance its capacitive deionization performance.

Quorum quenching bacteria bioaugmented GO/PPy modified membrane in EMBR for membrane antifouling

A novel integrated system with quorum quenching (QQ) bacterium Burkholderia sp. ssn-2 bioaugmented graphene oxide/polypyrrole (GO/PPy) conductive polymercomposite membrane (CPM) in MBR with electric field (EMBR) was established. The integrated system exhibited the highest degradation efficiency for phenol (100%) and COD (93.2%–99.9%) during the 120 days operation. Membrane fouling in the integrated system was notably mitigated by the coupling effect of CPM + voltage and QQ bacterium ssn-2. The hydrophilicity and antibacterial activity of CPM inhibited the hydrophobic protein foulants adsorption, bacteria colonization and attachment on the CPM surface. Extracellular polymeric substances (EPS) content was positively correlated with N-acyl-homoserine lactones (AHLs) concentration, and decreased with AHLs degradation by QQ bacterium ssn-2. The increased negative charge of EPS on the CPM surface augmented the electrostatic repulsion between the EPS and cathode CPM in the integrated system. Moreover, the coupling effect altered the microbial communities. A decreased AHLs concentration had a significantly negative correlation with QQ bacterium ssn-2 enrichment, which exhibited the dual effects of degrading phenol and AHLs, and enriching biopolymer-degrading genera Clostridium sensu strict and Acidovorax in the integrated system and on the CPM surface. This can lead to a decrease in the EPS content.

Synthesis of Graphene Oxide/Polypyrrole (GO/PPy) from Used Batteries as Electrodes in Supercapacitor Cells

Fabrication with graphite-modified GO/PPy composites have been studied from used batteries using the Hummers method. This research was performance in four steps: graphite powder preparation, GO synthesis, GO/PPy composite synthesis, and supercapacitor cell manufacturing. The results of the study were characterized using X-Ray Diffraction (XRD) to see the character of the diffraction patterns formed by carbon batteries used before and after calcination and Fourier Transform Infra-Red (FTIR) to identify compound functional groups and conduct initial tests in the form of voltage, capacitance and life cycle by measuring charge and discharge times. The graphite preparation stage is carried out by the calcination method at 900°C to produce graphite with an angle of 2θ which is 26° with reflection from (d002). FTIR data showed that GO/PPy composites showed a successful combination of characteristics similar to pure polypyrrole and GO which included a broad absorption band located at 3500-2300 cm-1 which was estimated to be stretching the amine from polypyrrole and O-H group in the GO layer and the emergence of peaks new in the absorption band with a wave number 909 cm-1 is the CN vibration of the polymerized pyrrole. Meanwhile, based on the LCR meter measurement results in the best supercapacitor cells in the sampel GO/PPy ratio (3:10) with voltage value of 74.1 mV; a capacitance value of 15.14 µF and the best charge and discharge times.

Porous Polypyrrole/Graphene Oxide Functionalized with Carboxyl Composite for Electrochemical Sensor of Trace Cadmium (II)

Cadmium (II) sensing utilizing three-dimensional graphene/polypyrrole oxides was applied and evaluated for the environmentally relevant analytes. Driven by the need to detect trace Cd (II), we prepared a porous graphene oxide-polypyrrole (pGO/PPy) polymer nanocomposite modified sensor for electrochemical trace analysis of Cd (II). The pGO/PPy was prepared by polypyrrole wrapped with graphene oxide using ultrasound-assisted polymerization and graphene oxide functionalized with carboxyl, which was modified on the sensing electrode for pre-concentration and enhanced the absorption of heavy metal ions. Three-dimension graphene oxide and interconnected porous structure of polypyrrole were fabricated by electro-polymerization and sonication to enhance the pre-concentration factors and the sensitivity for cadmium determination. The cadmium sensor fabricated with pGO/PPy nanocomposite displayed a displayed a considerable sensitivity within the linear range from 1μg·L−1 to 100 μg·L−1, a detection limit of 0.05 μg·L−1 2-orders-lower cadmium than the WHO standard limit. The cadmium sensor could be applied in tap, pond and river water with a high selectivity minimizing electroactive, interfering ions.

3D structures of graphene oxide and graphene analogue MoS2 with polypyrrole for supercapacitor electrodes

Transition metal dichalcogenides (TMDs) like Molybdenum disulfide (MoS2) are confessed as an effective energy storage materials due to their 2D structure analogues to graphene. Robust 3D architectures of graphene oxide-polypyrrole (GO-PPy) and molybdenum disulfide-polypyrrole (MoS2-PPy) were fabricated by facile, one pot chronoamperometry method to achieve scalable, conductive additive free and binder free supercapacitor electrodes. The electrodeposited GO-PPy and MoS2-PPy electrodes exhibit the specific capacitance of 271 F g−1 and 130 F g−1 respectively at a current density of 1 A g−1. The introduction of reduced graphene oxide (rGO) in PPy matrix offered high capacitance, whereas graphene analogue MoS2 improved the structural stability. Pronounced cycling stability (>2000 cycles) and note-worthy capacitive retentions were also displayed by these composites. MoS2-PPy and GO-PPy retain 82 and 64% of its initial capacitance respectively. These findings are backed up by the correlation of structure and electrochemical performance of GO-PPy and MoS2-PPy.

Graphene oxide-polypyrrole composite as sulfur hosts for high-performance lithium-sulfur batteries

Lithium-sulfur batteries are considered as a promising candidate for the next-generation high energy density storage devices. However, they are still hindered by serious capacity decay on cycling caused by the dissolution of redox intermediates. Here, we designed a unique structure with polypyrrole (ppy) inserting into the graphene oxide (GO) sheet for accommodating sulfur. Such a sulfur host not only exhibits a good electronic and ionic conductivity, but also can suppress polysulfide dissolution effectively. With this advanced design, the composite cathode showed a high specific capacity of 548.4[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] at 5.0 C. A stable Coulombic efficiency of [Formula: see text]99.5% and a capacity decay rate as low as 0.089% per cycle along with 300 cycles at 1.0 C were achieved for composite cathodes with 78[Formula: see text]wt.% of S. Besides, the interaction mechanism between PPy and lithium polysulfides (LPS) was investigated by density-functional theory (DFT), suggesting that only the polymerization of N atoms can bind strongly to Li ions of LPS rather than single N atoms. The 3D structure GO-PPy host with high conductivity and excellent trapping ability to LPS offered a viable strategy to design high-performance cathodes for Li–S batteries.

Electrochemical determination of phenothrin in fruit juices at graphene oxide-polypyrrole modified glassy carbon electrode

An electrochemical sensor was developed based on graphen oxide-polypyrrole modified glassy carbon electrode (GO/PPy/GCE) for sensitive determination of phenothrin in fruit samples. GO/PPy/GCE was characterized by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible spectroscopy (UV–Vis) and Raman spectroscopy. The sensor was also characterized using electrochemical impedance spectroscopy and cyclic voltammetry. Compared to bare GCE, GO/GCE and PPy/GCE, the reduction peak current of phenothrin increased significantly at GO/PPy/GCE, demonstrating that GO/PPy/GCE exhibited electrocatalytic activity towards the reduction of phenothrin. Under the optimal conditions, the sensor showed a linear relationship over the range of 2.5 × 10−8-2.0 × 10−5 M with detection limits of 13.8 × 10−9 M. In addition, the analytical application of the proposed method was carried out by the determination of phenothrin in fruit juice samples.

Enzymatic in situ synthesis of graphene oxide/polypyrrole composites by peroxidase and their electrical capacitance

AbstractRecently, diverse composites between carbon nanomaterials and conducting polymers have been intensively investigated for a variety of applications such as sensors and supercapacitors. These composites have been synthesized by either chemical or electrochemical methods, which have the drawbacks of using toxic oxidants or requiring complicated apparatus, respectively. The present study reports that the graphene oxide/polypyrrole (GO/PPy) composites can be easily synthesized in a single‐step catalyzed by horseradish peroxidase in an aqueous solution (pH 4.0). Scanning electron microscopy of the enzymatically synthesized GO/PPy composites shows that GO sheets are evenly coated with PPy without observable granular PPy particles. A symmetric two‐electrode coin cell capacitor (20 mm in diameter and 1.6 mm in thickness) was made to measure the electrical capacitance in an aqueous electrolyte (1 mol/L NaNO3) by the galvanostatic charge/discharge method. When the discharge current was 0.5 mA, the specific capacitance of the GO/PPy composites (46.6 F/g) was ∼390 times greater than graphene oxide (0.12 F/g) or ∼7 times greater than polypyrrole (6.7 F/g). Furthermore, the addition of a 0.2 L/L (20 vol%) water‐miscible ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM][BF4]), into the aqueous electrolyte enhanced the capacitance of the GO/PPy composites by 57 % at maximum.