Functionalized Reduced Graphene Oxide Research Articles

Synergistic effects of rGO functionalization in nanocomposite-based triboelectric nanogenerators for enhanced energy harvesting

Enhancing the performance of triboelectric nanogenerators (TENGs) by integrating advanced energy materials is crucial for broadening their applications. In this study, the tribo-positivity of polyvinyl alcohol (PVA) is physically tailored by doping with functionalized reduced graphene oxide (FrGO) into the polymer matrix, aiming to design high-performance TENGs. The pristine PVA and -OH, -COOH, and -NH2 FrGO nanocomposite with varying filler quantities (0–2 wt/wt%) are subjected to various characterizations for elucidating structural, surface and electrical properties. Further, electrical measurements of as-fabricated FrGO-TENGs revealed a notable increase in both voltage and current with increasing filler quantities. Interestingly, the NH2 FrGO-TENG shows maximum electrical output compared to –OH and –COOH FrGO-TENGs. Also, the open-circuit voltage (VOC) and short-circuit current (ISC) of NH2 FrGO-TENG are about 10 and 17 times more than that of pristine PVA-TENG. This substantial improvement is attributed to the extensive hydrogen bonding between the PVA-NH2 FrGO. Furthermore, the practical utility of the optimized device is demonstrated by showcasing its ability to power LEDs, digital timers, and commercial capacitors through a rectifier bridge. Thus, the results proved the potential of incorporating -NH2 FrGO into PVA as a synergistic material for sustainable and improvised energy harvesting, owing to opening new avenues for self-powered applications.

Yttrium Functionalized Reduced Graphene Oxide Nanocomposite-Based Aptasensor for Ultrasensitive Detection of a Breast Cancer Biomarker

Yttrium Functionalized Reduced Graphene Oxide Nanocomposite-Based Aptasensor for Ultrasensitive Detection of a Breast Cancer Biomarker

Correction to “Ultratough, Ductile, Castor Oil-Based, Hyperbranched, Polyurethane Nanocomposite Using Functionalized Reduced Graphene Oxide”

Correction to “Ultratough, Ductile, Castor Oil-Based, Hyperbranched, Polyurethane Nanocomposite Using Functionalized Reduced Graphene Oxide”

Novel Electrochemical Sensor for the Determination of Bisphenol A Using a Molybdenum(IV) Sulfide Quantum Dots Polysodium Styrene Sulfonate Functionalized Reduced Graphene Oxide Modified Glassy Carbon Electrode (GCE) by Differential Pulse Voltammetry (DPV)

A sensitive electrochemical platform for the determination of bisphenol A (BPA) was constructed. A hybrid of MoS2 quantum dots decorated poly sodium styrene sulfonate functionalized reduced graphene oxide (MoS2 QDS@PSS-rGO) was prepared by a simple method. The hybrid was cast on a bare glassy carbon electrode (GCE) to form the MoS2 QDs@PSS-rGO/GCE. The electrochemical response of BPA on the MoS2 QDs@PSS-rGO/GCE was significantly enhanced compared to the unmodified electrode, indicating that the nanocomposite possessed an electrocatalytic effect. A novel method was established to determine BPA with a detection limit of 0.008 μM. The applicability of the prepared sensor was demonstrated to determine BPA in real samples with high recoveries.

A novel nitrogen- and sulfur-grafted reduced graphene oxide doped with zinc cations for corrosion mitigation of mild steel

Grafting of N- and S- compounds on the reduced graphene oxide results in an increase in corrosion protection properties. In this work, for the first time, simultaneous grafting of both N- and S- atoms on the graphene oxide was accomplished using a natural source, Allium Sativum extract (ALS), which is rich in nitrogen and sulfur functionalities. The synthesis of sulfur- and nitrogen-grafted reduced graphene oxide (FrGO) was conducted using the hydrothermal route, and zinc cations were loaded on the FrGO consecutively. X-ray photoelectron microscopy (XPS) substantiated the successful grafting of ALS on the graphene oxide surface. The obtained products were characterized using diverse means, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Raman, UV–Vis, contact angle measurement, and thermogravimetric analysis (TGA). The morphology of the samples was determined using field emission scanning electron microscopy (FE-SEM). The incorporation of S, N, and Zn atoms was ascertained using dispersive X-ray spectroscopy (EDS) analysis. The synthesized substances, including graphene oxide (GO), functionalized/reduced graphene oxide (FrGO), and Zn loaded FrGO (Zn@FrGO), were used to prepare anti-corrosion epoxy coatings. The formulated coatings were evaluated using FE-SEM, electrochemical impedance spectroscopy (EIS), and salt spray test (SST). A considerable impact of the Zn@FrGO on the active corrosion protection properties was observed, which makes it a good candidate to be used as a replacement for toxic inhibitive substances.

Highly Water-Dispersible Methylpyridinium Salt Functionalized Reduced Graphene Oxide and Poly(Vinyl Alcohol) Composites

Highly Water-Dispersible Methylpyridinium Salt Functionalized Reduced Graphene Oxide and Poly(Vinyl Alcohol) Composites

Fabrication of High Dielectric Materials Through Selective Insertion of Functionalized Reduced Graphene Oxide on Hard Segment of Thermoplastic Polyurethane.

The presence of microcapacitors near percolatrion threshold determines dielectric permittivity of a material. Motivated by this concept, we focused our work by preferentially allocating functionalized reduced graphene oxide (FRGO) in hard segment (disperse phase) of Thermoplastic polyurethane (TPU) by solution blending method and characterized. Morphological studies of TPU/FRGO nanocomposites established homogeneous dispersion of FRGO throughout the TPU matrix. It is noted that TPU/FRGO (1 phr) nanocomposites exhibit maximum increase in tensile strength (33%) and elongation at break (10%). Thermogravimetric analysis (TGA) showed maximum enhancement in onset of decomposition temperature (~6 °C) in 2 phr FRGO loaded TPU. Differential scanning calorimetry (DSC) analysis showed maximum reduction (~2 °C) in glass transition temperature (Tg) of soft segment of TPU followed by maximum improvements in melting temperature (~4 °C) as well as crystallization temperature (~22 °C) of hard segment compared to neat TPU. Further, a significantly high value of dielectric permittivity (401) is achieved in 1.5 phr loaded FRGO at 100 Hz due to the formation of significantly higher number of microcapacitors near the percolation threshold. It is anticipated that such thermally stable and mechanically strong high dielectric TPU/FRGO nanocomposites can find applications in the field of electronic devices.

Facile Route for the Preparation of Functionalized Reduced Graphene Oxide/Polyaniline Composite and Its Enhanced Electrochemical Performance

A functionalized reduced graphene oxide/polyaniline (FRGO/PANI) composite is fabricated with a facile and practical approach, including the reduction and functionalization of graphene oxide (GO) and in situ polymerization of polyaniline (PANI) on the surface of functionalized reduced graphene oxide (FRGO). Amino groups are introduced to the surface of FRGO in the solvothermal reduction process. The composite exhibits a specific capacitance of 421 F g−1 at 0.6 A g−1, showing an outstanding improvement than pure PANI (298 F g−1) and FRGO (113 F g−1). Meanwhile, the capacitance retention for FRGO/PANI composite after 800 cycles is 84.6%, which is superior to pure PANI of 50.8%. The synergistic effect between FRGO and PANI makes a great contribution to the enrichment of electrochemical performance. The consequence shows that FRGO/PANI composite synthesized in this way has promising feasibility for applications in high-performance supercapacitor electrode materials.

Electrochemical Sensor for Detection of p‐Nitrophenol Based on Nickel Oxide Nanoparticles/α‐Cyclodextrin Functionalized Reduced Graphene Oxide

Abstractp‐Nitrophenol (p−NP) is a high priority toxic pollutant and that has harmful effects on human, animals and plants. Thus, the detection and determination of p−NP present in the environment is an urgent as well as highly important requisite. The present article, therefore focused on the construction of a novel electrochemical sensor based on NiO nanoparticles/α‐cyclodextrin functionalized reduced graphene oxide modified glassy carbon electrode (NiO−NPs‐α‐CD‐rGO‐GCE) for the selective and sensitive detection of p−NP. UV‐vis, high resolution transmission electron microscopy (HR‐TEM), selected area electron diffraction pattern (SAED) and X‐ray diffraction (XRD) analysis confirms the formation of highly pure NiO nanoparticles. Field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray spectroscopy (EDS), and cyclic voltammetry (CV) were used to characterize the step‐wise electrode modification process. DPV was carried out to quantify p−NP within the concentration range of 1−10 μM and found the detection limit of 0.12 nM on the basis of the signal‐to‐noise ratio S/N=3. The electrode can able to detect different isomers of nitrophenols. Interferences of other pollutants such as phenol, p‐aminophenol, o‐ and m‐ nitrophenol, 4‐chlorophenol, 2,6‐dichlorophenol and ions like K+, Cd2+, Cl−, SO42− did not affect the sensing of p−NP. The newly developed sensor exhibited diffusion controlled kinetics and had excellent sensitivity, selectivity and reproducibility for the detection of p−NP. The electrode showed good recoveries in real sample analysis.

Voltammetric Detection of Nitrite Anions Employing Imidazole Functionalized Reduced Graphene Oxide as an Electrocatalyst

AbstractA kind of metal free catalyst with excellent electrocatalytic activity toward nitrite anions oxidation was synthesized through functionalization of graphene oxide (GO) with imidazole aromatic rings. Imidazole rings linked to graphene oxide nanosheets via 3‐chloropropyl trimethoxysilane (CPTMS) mediators following simultaneous thermally reduction of GO during the functionalization, to form rGO−Im for modification of gold electrode (GE). The sensing platform characterized by SEM, XRD, IR and Raman methods. The resulting rGO−Im‐GE sensor, responded sensitively to nitrite concentrations within a wide linear range (1 to 1000 μM) and indicated a relative low detection limit (LOD=0.28 μM, S/N=3) without interfering with common ions existing in aqueous media. Furthermore acceptable recoveries were obtained when applying the proposed sensor to tap water samples.

Synthesis of reduced graphene oxide functionalized with methyl red dye and its role in enhancing photoactivity in TiO2–IL/WO3 composite for toluene degradation

A nanostructured composite material was produced through sol–gel-assisted ionic liquid (IL) synthesized TiO2, WO3 and functionalized reduced graphene oxide (FRGO), respectively. IL was selected and used as shape and size controller in TiO2 synthesis as well. GO nanosheets were functionalized with (E)-2-[4-(dimethylamino) phenyl] benzoic acid (methyl red dye) in order to absorb more light. The products were characterized using X-ray diffraction spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption methods, FTIR, Raman, photoluminescence and X-ray photoelectron spectroscopy. The photocatalytic activity of TiO2–IL/WO3/FRGO composite in toluene degradation under visible-light irradiation was evaluated by gas chromatography. The prepared composite demonstrated significant toluene degradation (ca. 74%) after only 2 min of reaction in comparison to TiO2–IL/WO3 composite (51%), TiO2–IL (40%) and pure TiO2 (17%). These results are due to the combination of FRGO and WO3 with TiO2 by their properties like stability, high surface area and low band gap.

CuS Decorated Functionalized Reduced Graphene Oxide: A Dual Responsive Nanozyme for Selective Detection and Photoreduction of Cr(VI) in an Aqueous Medium

Design of functional nanomaterials as peroxidase mimics has attracted great attention due to promising applications in numerous fields, including biosensing, cancer diagnostics, immunoassays, envir...

Formulation of a promising antimicrobial and anticorrosive bi-functional boronated hyperbranched oleo-polyurethane composite coating through the exploitation of functionalized reduced graphene oxide as chain extender

Herein, a facile route was employed for the construction of novel dual-functional boronated (hybrid) hyperbranched polyurethane composite (HPUC) coatings using covalently functionalized reduced graphene oxide (FRGO) as chain extender and reinforcing agent. The FRGO exhibited excellent compatibility with the boronated HPU matrix that resulted in the chemical, structural and surface transformation of FRGO-HPUC coatings. The electrochemical corrosion studies were employed to confirm the protective performance of these composite coatings. The presence of electron deficient centres (tri-coordinated B) and electron rich FRGO restricted the diffusion of electrons through the coating network, which altered the mechanism of corrosion protection. In addition, the antimicrobial surface activity of these composites were investigated to ascertain their permanent contact killing properties.

Effect of reduction methods and functionalization on the dispersion of graphene in epoxy

Poor dispersion between graphene nanofiller and polymer matrix would limit the development and application of the polymeric composites. In our study, three reduction methods, chemical reduction using hydrazine hydrate (N2H4·H2O), high temperature, and solvothermal methods were used to reduce graphene oxide; then reduced graphene oxide (RGO) were further functionalized by sodium dodecyl benzene sulfonate (SDBS) and cetylpyridinium chloride (CPC). The functionalized RGO (FRGO) was characterized with Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, respectively. Subsequently, the studied RGO was incorporated into epoxy resin to fabricate composites. Hansen solubility parameters (HSPs) theory was used to predict dispersion of studied RGO in epoxy resin. The compatibility of different RGO with epoxy was calculated by HSPs and compared with the real dispersion of RGO and FRGO in epoxy resin, which was explored through light optional microscopy (LOM). The results indicated that the dispersion of studied RGO in epoxy predicted by HSPs theory is in a good agreement with the experimental results.

Fabrication, characterization and electromagnetic wave absorption properties of covalently modified reduced graphene oxide based on dinuclear cobalt complex

We are reporting on well-designed single-layered and gradient concentration triple-layered microwave-absorbing composites based on functionalized reduced graphene oxide (FRGO). The RGO-[Co2L2Cl3]Cl, called FRGO, was fabricated through systematic experimental efforts by the covalent attachment of the 2,6-diamino-3-[(2-carboxylicacid) phenylazo]-pyridine (L)/Cobalt (Co) complex with graphene oxide (GO) functionalities. The formation of FRGO was proven by a series of characterization techniques, such as XPS, FTIR, XRD, Raman spectroscopy, FESEM, and TEM. The consideration of RGO-[Co2L2Cl3]Cl as a highly efficient microwave-absorbing material is a result of its magnetoelectric synergistic effect, impedance match, and multiple scattering. The maximum reflection loss (RL) of single-layered an RGO-[Co2L2Cl3]Cl/epoxy resin composite can reach −16.32 dB at 8.69 GHz, which corresponds to a composite with 30 wt % absorber loading and a thickness of 4.5 mm. For the triple-layered composite with increasing mass percentage (10–20–30 wt %) of RGO-[Co2L2Cl3]Cl in the direction of microwave propagation, the maximum reflection loss value of −34.9 dB can be achieved at 10.69 GHz, with a coating layer thickness of 4.5 mm. The result demonstrates that the RGO-[Co2L2Cl3]Cl/epoxy resin composites of both models can be ideal microwave-absorbing candidates for application in the X-band.

Functionalized Graphene for Mechanical Property Enhancement of Polymer Composites.

Because of its high strength and high toughness, graphene has been widely used in mechanical reinforced composites. In general, the mechanical enhancement depends mainly on the properties of graphene itself and the number of surface chemical functional groups attached on it. In this paper, we report a method to improve the mechanical performance of polymer by using a kind of functionalized reduced graphene oxide (F-RGO), i.e., the F-RGO is prepared by chemical treatment, and then the F-RGO/polyvinylidene fluoride (PVDF) composite films are obtained by spin coating. Because the chemical treatment can increase the number of functional groups on the surface and edge of F-RGO, these functional groups make the F-RGO sheets strongly coupled with PVDF molecules, so as to achieve the purpose of mechanical enhancement. The experimental results reveal that the mechanical properties of the F-RGO/PVDF composite films are improved for 42% times, when comparing with regular RGO/PVDF composite films.

In–situ hybridization of polyaniline nanofibers on functionalized reduced graphene oxide films for high-performance supercapacitor

High-performance hybrid supercapacitor is still hampered by lacking of proper electrode materials of desired nanostructures. However, the hybridization of polyaniline (PANI) on functionalized reduced graphene oxide (FrGO) could form such desired nanostructure with uniform graphene distribution, high carriers density and significantly improved cycling stability and rate capability of PANI. Here we report a facile process for the hybridization of polyaniline nanofibers (PANI NFs) on functionalized reduced graphene oxide (FrGO) films by filtering the hybrid suspension of graphene oxide (GO) and in-situ polymerized PANI NFs followed by hydrothermal treatment to reduce GO and sulfur functionalization of rGO. The as-prepared PANI NFs/FrGO composite films were uniform, flexible and stable with a high specific capacitance of 692.0 F/g at 1 A g−1 and an excellent capacitance retention of 53.5% at 40 A g−1. Furthermore, the assembled all-solid-state supercapacitor using the as-prepared composite films as electrodes exhibited a high capacitance of 324.4 F/g at 1 A g−1 and an energy density ∼16.3 Wh kg−1 at a power density of 300 W kg−1, showing a great promising in the applications for portable power and flexible supercapacitor.

In Vivo Dopamine Biosensor Based on Copper(I) Sulfide Functionalized Reduced Graphene Oxide Decorated Microelectrodes.

A novel dopamine biosensor based on carbon fiber microelectrodes (CFMEs) modified with copper(I) sulfide functionalized nanocomposites of the reduced graphene oxide (Cu2S/RGO) has been explored for the sensitive detection of dopamine and in vivo monitoring the neurotransmitters released by Drosophila's brain. The as-prepared Cu2S/RGO decorated microelectrodes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Our observations demonstrate that Cu2S/RGO-CFMEs exhibited excellent catalytic activity and high selectivity for dopamine with relatively low detection limit (24 nM), wide linear range (i.e., from 0.1-20 μM) and outstanding reproducibility. Furthermore, the as-prepared new dopamine biosensor with high sensitivity and good stability was readily used to detect the amount of dopamine in the brain of drosophila, indicating the potential and promising application in the in vivo measurement of neurotransmitters without other electrochemical interference such as histidine, ascorbic acid, uric acid, and others.

The loading of polyoxometalates based compound on reduced graphene oxide, a composite material for electrical energy storage and tetracycline removal

A polyoxometalate based composite material (NiPW12NP/FrGO) was synthesized successfully, in which the nanoparticle of a polyoxometalate compound (NiPW12NP) distributes on carboxylate group functionalized reduced graphene oxide (FrGO) homogenously. There exist intensive chemical bonds between NiPW12NP and FrGO, which guarantees the stability of this composite material. When employed as a cathode material, NiPW12NP/FrGO exhibits high specific capacitance, remarkable rate capability and long-term stability. When the current density is 4 A g−1, a specific capacitance as high as 437.6 F g−1 is achieved by NiPW12NP/FrGO. With NiPW12NP/FrGO serving as cathode and MnO2 acting as anode, a high performance asymmetric supercapacitor (ASC) is assembled, which possesses a high energy density of 12.96 W h·kg−1 at 0.67 kW kg−1. It also shows a good rate capability, when the current density increases from 4 to 12 A g−1, its specific capacitances decreases from 115.2 to 90.9 F g−1, with 78.9% capacitance retention. After 5000 cycles charge-discharge experiments, 94.3% of its capacitance can be maintained, which exhibits good stability. Furthermore, NiPW12NP/FrGO composite material also shows excellent tetracycline adsorption ability with capacity 288.28 mg g−1, the adsorption can be well described with Temkin model, which suggests electrostatic attraction dominates the adsorption process.

Flexible Asymmetric Supercapacitor Based on Functionalized Reduced Graphene Oxide Aerogels with Wide Working Potential Window.

Flexible energy storage devices are in great demand since the advent of flexible electronics. Until now, flexible supercapacitors based on graphene analogues usually have had low operating potential windows. To this end, two dissimilar electrode materials with complementary potential ranges are employed to obtain an optimum cell voltage of 1.8 V. A low-temperature organic sol-gel method is used to prepare two different types of functionalized reduced graphene oxide aerogels (rGOA) where Ag nanorod functionalized rGOA acts as a negative electrode while polyaniline nanotube functionalized rGOA acts as a positive electrode. Both materials comprehensively exploit their unique properties to produce a device that has high energy and power densities. An assembled all-solid-state asymmetric supercapacitor gives a high energy density of 52.85 W h kg-1 and power density of 31.5 kW kg-1 with excellent cycling and temperature stability. The device also performs extraordinarily well under different bending conditions, suggesting its potential to meet the requirements for flexible electronics.