Polypyrrole-reduced Graphene Oxide Research Articles

Polypyrrole/reduced graphene oxide composite as a low-cost novel sensing material for fast-response humidity sensor

In this study, the polypyrrole/reduced graphene oxide (PrGO) composites' ability to detect humidity was investigated. Polypyrrole (PPy), a chemically produced oxidative polymer, was physically blended, for these observations in accordance with the feeding mass ratio of reduced graphene oxide (rGO). The Hummers process is utilized to produce graphene oxide (GO), which is then quickly and easily reduced to rGO by adding a small amount of selenium power. To determine the functional and morphological characteristics of the produced PrGO composites XRD, FTIR, RAMAN, SEM, and TEM characterisations were performed. To know about the humidity sensing performances, The thin film of PPy, Polypyrrole/Graphene oxide (PGO), and PrGO composites were prepared by wedging the sample on a basic glass plate using a low-cost spin coating approach. Among all the samples prepared, the PrGO composite demonstrated a sensing response of 99.99%, with a quick response and recovery time of 2 s and 4 s, respectively. The ideal characteristics such as high real sensitivity, lower limits of detection (LOD), minimal hysteresis, and perfect stability were established by PrGO composite. When compared to PPy and PGO composite, the physical properties of PrGO composite have significantly improved, including porosity, water content, and degree of swelling compare to other samples. A detailed discussion of the humidity sensing system has been made.

Isolated Cu-N5 sites engineered polypyrrole-reduced graphene oxide hybrids for enhancing room-temperature DMMP sensing

The hydrogen bonding interactions are potentially employed to fabricate high-performance room-temperature gas sensors for detection of organophosphorus. Nevertheless, the low response toward target gases of conventional sensing materials hinders their further applications. Herein, an isolated Cu-N5 sites engineering strategy is reported to improve sensing performances for polypyrrole-reduced graphene oxide hybrids (PPy-rGO)-based room-temperature dimethyl methyl phosphate (DMMP) sensors. The isolated Cu-N5 sites were simply constructed by adsorption of Cu2+ ions with PPy-rGO hybrids owing to strong metal-support interactions. X-ray absorption fine structure analysis indicates that Cux+ ions with mean chemical valence of + 1.07 nearly atomically distributed on support with coordination structure of Cu-N5. Benefiting from the structure regulation by Cux+ ions, as-constructed DMMP sensor demonstrated 4.5-fold improvement in response to 100 ppm DMMP and 2.5-fold improvement in limit of detection, compared to PPy-rGO hybrids. The density functional theory, spectroscopic characterizations and quartz crystal microbalance tests prove that the construction of Cu-N5 sites not only heightens hydrogen bonding interactions between NH bonds and DMMP molecules induced by newly formed coordination interactions between Cux+ ions and NH bonds, but also serves as new active sites for adsorption of DMMP molecules. This work offers a new avenue for developing high-performance room-temperature gas sensors by heightening hydrogen bonding interactions.

Polypyrrole-reduced graphene oxide coated delignified wood for highly efficient solar interfacial steam generation

A solar interfacial steam generator is a device that localizes the solar energy at the water–air interface for water evaporation. The solar interfacial steam generator can be applied in various evaporation-based thermal systems to enhance system efficiency by reducing heat dissipation. In this study, a bio-inspired polypyrrole-reduced graphene oxide coated wood was fabricated and investigated for evaporation and solar-to-vapor conversion efficiency improvement with different polypyrrole-reduced graphene oxide ratios. Thanks to the synergistic effect of highly solar-absorbed polypyrrole and water-attracted reduced graphene oxide, and the efficient heat transfer two-dimensional pathway, the polypyrrole-reduced graphene oxide coated wood showed an outstanding water evaporation performance. The highest water evaporation rate obtained by the polypyrrole-reduced graphene oxide coated wood with the reduced graphene oxide content of 60 % was 1.49 kg·m−2·hr-1, showing a nearly 10 % and 19 % improvement compared to polypyrrole and reduced graphene oxide coated woods, respectively. The corresponding solar-to-vapor conversion efficiency (93.1 %) was also beyond most of the wood-based interfacial steam generators in the literature. The transient heat transfer and evaporation performances of the polypyrrole-reduced graphene oxide coated wood were also firstly investigated based on the developed transient models. It is expected that the remarkable results of this study can help to promote and facilitate the study and application of interfacial steam generators in various thermal systems.

Polypyrrole-Reduced Graphene Oxide Coated Delignified Wood for Highly Efficient Solar Interfacial Steam Generation

Polypyrrole-Reduced Graphene Oxide Coated Delignified Wood for Highly Efficient Solar Interfacial Steam Generation

Hydrogen bonds-induced room-temperature detection of DMMP based on polypyrrole-reduced graphene oxide hybrids

The development of fast-response, high sensitivity and selectivity gas sensors for monitoring of organophosphorus is essential, where two dimensional graphene-based materials possessing exceptionsal carrier mobility are considered as promising candidates for room-temperature organophosphorus detection. However, it is challenging to fabrication of graphene-based gas sensors for detection of organophosphorus with excellent sensing performances. Herein, we develope a self-redox strategy to synthesize polypyrrole decorated-reduced graphene oxide hybrids (PPy-rGO) by redox reactions between pyrrole and GO during hydrothermal treatment process. This self-redox strategy results in the formation of perfact interfical strucutre between PPy and rGO through the π-π interactions without the impurity from the conventional oxidation/reducing agents. Most importantly, such PPy-rGO hybrids can be used as novel sensing materials for detection of dimethyl methylphosphonate (DMMP) at room temperature. Specially, the response of PPy-rGO-based sensor towards 100 ppm DMMP can reach 12.9 %, which is 3-fold higher than that pristine rGO-based sensor. Meanwhile, PPy-rGO-based sensor exhibits short response time/recovery time (43 s/75 s), low detection limit (5 ppm), excellent repeatability, and high selectivity. By combination of FT-IR and N2 sorption isotherms, the enhanced DMMP sensing performances of PPy-rGO hybrids are concluded as following two aspects. Firstly, the formation of hydrogen bonds between PPy-rGO hybrids and DMMP molecules regulates the adsorption/desorption of DMMP. Secondly, increasing BET surface area by introduction of PPy into rGO matrix is beneficial to DMMP diffusion among the sensing materials. Our work would offer a new strategy for rational development of graphene-based materials for detection of organophosphorus at room temperature.

Polyoxometalate-Templated Cobalt-Resorcin[4]arene Frameworks: Tunable Structure and Lithium-Ion Battery Performance.

By employing a bowl-like tetra(benzimidazole)resorcin[4]arene (TBR4A) ligand, two new polyoxometalate-templated metal-organic frameworks (POMOFs), [Co8Cl14(TBR4A)6]·3[H3.3SiW12O40]·10DMF·11EtOH·20H2O (1) and [Co3Cl2(TBR4A)2(DMF)4]·[SiW12O40]·2EtOH·3H2O (2), have been prepared under solvothermal conditions (DMF = N,N'-dimethylformamide). 1 shows a 2D cationic layer, whereas 2 exhibits a 3D framework. Remarkably, the Keggin POMs in 1 and 2 were located in the cavities formed by two bowl-like resorcin[4]arenes in sandwich fashions. Their framework structures were highly dependent on the coordination modes of the TBR4A ligands. To increase the conductivity of POMOFs, the samples of 1 and 2 were loaded on the conductive polypyrrole-reduced graphene oxide (PPy-RGO) via ball milling (1@PG and 2@PG). Then, the obtained composites experienced calcination at a proper temperature to produce 1@PG-A and 2@PG-A. The resulting 1@PG-A and 2@PG-A composites, with improved conductivities, uniform sizes and micropores, exhibited promising electrochemical performance for lithium-ion batteries. We herein proposed a size-controlled route for the rational fabrication of functional POMOFs and their usage in energy fields.

Simultaneous determination of dihydroxybenzene isomers using a three-dimensional over-oxidized polypyrrole–reduced graphene oxide composite film electrode prepared by an electrochemical method

A 3D-over-oxidized polypyrrole–reduced graphene oxide composite film was prepared by an electrochemical procedure, which showed high electrochemical activity and good selectivity for simultaneous determination of dihydroxybenzene isomers.

Facile electrochemical preparation of overoxidizedpolypyrrole/RGO composite for ds-DNA immobilization: a novel signal amplified sensing platform for electrochemical determination of chlorpheniramine.

Chlorpheniramine (CPA), thanks to its relatively lower side effects, is a widely prescribed medicine for alleviating allergic symptoms as well as some medical emergencies. Owning to this extensive use, many efforts have been directed to measure chlorpheniramine both in vivo and in vitro. High performance liquid chromatography (HPLC), both normal and reverse phase, as well as spectrochemical and electrochemical methods are analytical approaches which have been extensively exploited for determination of CPA. Among them, electrochemical techniques have found elegant place for analysis of CPA due to simplicity, sensitivity and ease of instrumentation. Herein, we have reported the preparation and characterization of a biosensor by immobilization of double-stranded DNA on the surface of overoxidizedpolypyrrole-reduced graphene oxide modified pencil graphite electrode (ds-DNA-PPyox/RGO/PGE) as well as its novel usability in measurement of chlorpheniramine (CPA). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), UV-Vis spectroscopy and differential pulse voltammetry (DPV) were exploited in order to characterize and evaluate the performance of the proposed biosensor. Final results showed that proposed strategy for modification of PGE introduces an ultra-sensitive biosensor for CPA which offers the best detection limitamong all previously reported electrochemical sensors for CPA. Taking advantage of this biosensor for determination of CPA, a wide linear dynamic range from 0.05 to 200μM, and a low limit of detection 0.023μM were obtained by using DPV method. Usability of this biosensor was also confirmed by determination of CPA in tablet and spiked urine samples. Overoxidized polypyrrole-reduced graphene oxide offered a suitable substrate for immobilization of ds-DNA by which a new biosensor for determination of CPA was fabricated. Proposed biosensor can successfully be used for determination of CPA in urine samples taking advantage of electroanalytical methods. Graphical abstract.

Electrochemical detection of Salmonella using an invA genosensor on polypyrrole-reduced graphene oxide modified glassy carbon electrode and AuNPs-horseradish peroxidase-streptavidin as nanotag

A rapid and sensitive electrochemical biosensor was constructed to detect Salmonella using invA gene biosensor. The biosensing was based on polyrrole-reduced graphene oxide (PPy-rGO) nanocomposite modified glassy carbon electrode (GCE) and signal amplification with horseradish peroxidase-streptavidin biofunctionalized gold nanoparticles (AuNPs-HRP-SA). PPy-rGO was prepared at 60 °C by chemical reduction of PPy-functionalized graphene oxide (PPy-GO) that was synthesized by in situ polymerization at room temperature. The detection signal was amplified via enzymatic reduction of H2O2 in the presence of hydroquinone (HQ) using AuNPs-HRP-SA as nanotag. Under optimal conditions, the differential pulse voltametric (DPV) signal from the biosensor was linearly related to the logarithm of target invA gene concentrations from 1.0 × 10−16 to 1.0 × 10−10 M, and the limit of detection (LOD) was 4.7 × 10−17 M. The biosensor can also detect Salmonella in the range of 9.6 to 9.6 × 104 CFU mL−1, with LOD of 8.07 CFU mL−1. The biosensor showed good regeneration ability, acceptable selectivity, repeatability and stability, which bode well as an alternative method for Salmonella screening.

Preparation and characterization of palladium/polypyrrole-reduced graphene oxide/foamed nickel composite electrode and its electrochemical dechlorination of triclosan

In this study, a new composite electrode of palladium (Pd) nanoparticles dispersed on polypyrrole-reduced graphene oxide (PPy-rGO) loaded on foam-nickel was achieved by galvanostatic method. Characterization of structures, morphology and crystallinity of the synthesized materials were investigated by scanning electron microscopes (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The results of XPS and XRD demonstrated Pd showed primarily as Pd0. From SEM and TEM results, we had seen that Pd nanoparticles were dispersible well on the composite electrode. Raman spectroscopy was used to show the state of graphene oxide and further demonstrated that PPy and rGO had existed of on the foam Ni matrix. The data of EIS also suggested the charge transfer of the new composite electrode decreased compared to Pd/PPy/foam-Ni and PPy/foam-Ni composite electrodes. The effect of the electropolymerization potential on Pd/PPy-rGO/foam-Ni electrode for removing triclosan (TCS) was examined. It was found that the removal efficiency of TCS on the composite electrode could reach 100% at electropolymerization potential of 0.7 V and reaction time of 100 min.

Electrodeposition⁻Assisted Assembled Multilayer Films of Gold Nanoparticles and Glucose Oxidase onto Polypyrrole-Reduced Graphene Oxide Matrix and Their Electrocatalytic Activity toward Glucose.

The study reports a facile and eco-friendly approach for nanomaterial synthesis and enzyme immobilization. A corresponding glucose biosensor was fabricated by immobilizing the gold nanoparticles (AuNPs) and glucose oxidase (GOD) multilayer films onto the polypyrrole (PPy)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) via the electrodeposition and self-assembly. PPy and graphene oxide were first coated on the surface of a bare GCE by the electrodeposition. Then, AuNPs and GOD were alternately immobilized onto PPy-RGO/GCE electrode using the electrodeposition of AuNPs and self-assembly of GOD to obtain AuNPs-GOD multilayer films. The resulting PPy-RGO-(AuNPs-GOD)n/GCE biosensors were used to characterize and assess their electrocatalytic activity toward glucose using cyclic voltammetry and amperometry. The response current increased with the increased number of AuNPs-GOD layers, and the biosensor based on four layers of AuNPs-GOD showed the best performance. The PPy-RGO-(AuNPs-GOD)4/GCE electrode can detect glucose in a linear range from 0.2 mM to 8 mM with a good sensitivity of 0.89 μA/mM, and a detection limit of 5.6 μM (S/N = 3). This study presents a promising eco-friendly biosensor platform with advantages of electrodeposition and self-assembly, and would be helpful for the future design of more complex electrochemical detection systems.

Gold nanoparticles-based multifunctional nanoconjugates for highly sensitive and enzyme-free detection of E.coli K12

Immobilization of proteins on a biocompatible conductive interface is highly desirable for the fabrication of biosensors. In this study, a nanocomposite has been prepared by assembling well-distributed gold nanoparticles (AuNPs) on the surface of a polypyrrole-reduced graphene oxide (PPy-rGO) composite through electrostatic adsorption. This serves as a platform for immobilization of a capture antibody, which was conjugated onto the ferrocene doped polypyrrole-gold nanoparticles (PPy@Fc/AuNPs) composite. The design and performance of the biosensor was tested against detection of a whole-cell bacteria E. coli K12. This nanocomposite has a high surface area, good conductivity and biocompatibility, which is shown to be very suitable for enzyme-free detection of this bacteria. Results show excellent analytical performance with a linear range from 1.0 × 101 to 1.0 × 107 CFU mL–1 and a low detection limit of 10 CFU mL–1. The sensor has high selectivity, excellent reproducibility, and good stability.

Polypyrrole-reduced graphene oxide nanocomposite hydrogels: A promising electrode material for the simultaneous detection of multiple heavy metal ions

We have studied the formation of novel hydrogels of conjugate polymer polypyrrole (PPy) and reduced graphene oxide (rGO) for the simultaneous detection of four different metal ions such as Cd2+, Pb2+, Cu2+ and Hg2+. PPy-rGO hydrogel composite exhibits very high surface area of 21.48 m2 g-1, which is almost 3.5 times higher than that of PPy (5.89 m2 g-1). The achieved detection limits were much lesser than the world health organisation (WHO) threshold limits and also very less compared to many polymer based heavy metal sensors.

Performance stability of solid-state polypyrrole-reduced graphene oxide-modified carbon bundle fiber for supercapacitor application

The stability performance of a solid-state polypyrrole-reduced graphene oxide (PPy-rGO) supercapacitor electrode after a series of charging-discharging cycles is investigated. The electrochemical performances show that the capacity retention, specific capacitance, equivalent series resistance, and charge transfer resistance all decrease after charging-discharging cycles. Thermogravimetric analysis shows the degradation of electroactive materials, causing decreased electrochemical performance of PPy-rGO. The morphology changes reveal that the pore size is reduced by ∼12 μm at the 1000th charge-discharge cycle, which limits the diffusion of electrolyte ions into the electrode. The positive shifts in the binding energy of the N1s spectra at the 500th and 1000th charge-discharge cycles indicate the formation of a hydrogen-bridge bond, affecting the electron transfer in the PPy-rGO composite as observed through X-ray photoelectron spectroscopy. Moreover, the structural properties of rGO change from amorphous to graphitic after a series of charging-discharging processes, as shown by the Raman spectra. Furthermore, the peak of the NH bending vibration is red-shifted by approximately 108 cm−1, indicating the changes in the chemical environment after a series of charging-discharging cycles, as shown by Fourier transform infrared spectroscopy.

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.

Improved dye entrapment–liberation performance at electrochemically synthesised polypyrrole–reduced graphene oxide nanocomposite films

In this work, we have reported the application of electropolymerised polypyrrole–reduced graphene oxide (Ppy–RGO) nanocomposite films as an effective tool for entrapping and liberating the model dye Acid Red 1, and thereby proposed this as an ecofriendly treatment for dye-containing textile effluents. Initially, a polypyrrole–graphene oxide (Ppy–GO) nanocomposite film was anodically synthesised by an in situ electropolymerisation of pyrrole and GO. The Ppy–GO film was then electrochemically reduced to form a Ppy–RGO nanocomposite film. The synthesised nanocomposite films were characterised by spectroscopy, microscopy, surface analysis and thermogravimetry. Brunauer, Emmett and Teller surface area analysis showed a 7.4-fold increase in surface area of Ppy–RGO films compared to that of $${\text{NO}}_{3}^{ - }$$ -polypyrrole films. In addition, based on tensile strength, Ppy–RGO films were demonstrated to be 12.7-folds mechanically stronger than $${\text{NO}}_{3}^{ - }$$ –Ppy films. When Acid Red 1 was entrapped in these films, an entrapment efficiency of as high as 95% for Acid Red 1 was achieved at Ppy–RGO films, which is significantly higher than 56% achieved at Ppy films. Similarly, while liberating the entrapped Acid Red 1 from the Ppy–RGO nanocomposite films, a liberation efficiency of 73% was estimated compared to 36% from the Ppy films.

Facile preparation of polypyrrole-reduced graphene oxide hybrid for enhancing NH3 sensing at room temperature

Polypyrrole (PPy)-reduced graphene oxide (rGO) hybrid was successfully synthesized by a facile in situ polymerization. The as-synthesized PPy nanoparticles with diameter of ca. 80nm were uniformly distributed on the surface of the rGO sheets to prepare the hybrid of PPy/rGO. Then the pure PPy and their hybrids were loaded on the substrate of flexible polyethylene terephthalate (PET) film to construct a thin film NH3 sensor, which has the advantages of being flexible, economical, portable and able to operable at room temperature (RT). The gas-sensing results reveal that the 5wt% rGO-PPy hybrid based sensor not only exhibits the highest response to 10ppm NH3, which is 2.5 times higher than that of pure PPy, but also excellent selectivity to some of VOCs. The enhancement of gas-sensing properties may be attributed to the π-π stacking and H-bonding formation between PPy and rGO, larger surface accessibility and fast transport of carriers.

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.

Supercapacitors based on highly dispersed polypyrrole-reduced graphene oxide composite with a folded surface

Highly dispersed polypyrrole particles were decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composite, which obtained a folded surface, shows remarkable performance as the electrode material of supercapacitors. The specific capacitance reaches 564.1 F g−1 at a current density of 1 A g−1 and maintains 86.4 % after 1000 charging–discharging cycles at a current density of 20 A g−1, which indicates a good cycling stability. Furthermore, the prepared supercapacitor demonstrates an ultrahigh energy density of 50.13 Wh kg−1 at power density of 0.40 kW kg−1, and remains of 45.33 Wh kg−1 even at high power density of 8.00 kW kg−1, which demonstrate that the hybrid supercapacitor can be a promising energy storage system for fast and efficient energy storage in the future.