Reduced Graphene Oxide Composite Film Research Articles

Free-Standing Poly(vinyl benzoquinone)/Reduced Graphene Oxide Composite Films as a Cathode for Lithium-Ion Batteries.

Quinones with a rapid reduction-oxidation rate are promising high-capacity cathodes for lithium-ion batteries. However, the high solubility of quinone molecules in polar organic electrolytes results in low cycle stability, while their low electric conductivity causes low utilization of electrode materials. In this article, a new p-benzoquinone derivative, poly(vinyl benzoquinone) (PVBQ), is designed and synthesized, and a solution-based method of preparing free-standing PVBQ/reduced graphene oxide (RGO) composite films is developed. PVBQ has a high theoretical specific capacity (400 mA h g-1) because of its low dead moiety mass. In the produced composite films, PVBQ nanoparticles are uniformly dispersed on RGO sheets, which endows the composite films with high electric conductivity and inhibits the dissolution of PVBQ through strong adsorption. As a result, the composite films show a high active material utilization, high practical specific capacity, and excellent cycling stability. PVBQ in the composite membrane containing 60.2 wt % RGO deliver 244 mA h g-1 capacity after 200 charge-discharge cycles at a current density of 300 mA g-1. At a current density of 1500 mA g-1, the reversible specific capacity is still 170 mA h g-1. This work provides a high-performance cathode material for lithium-ion batteries, and the molecular structure and electrode structure design ideas are also instructive for developing other organic electrode materials.

Nacre inspired supertough and flame-retardant reduced graphene oxide composite films

Nacre-like graphene composite films (GCFs) with high strength have been highly developed. However, the GCFs usually exhibit relatively poor toughness and poor flame resistance, seriously limiting their applications as structural materials. Here, reduced graphene oxide (rGO), halloysite nanotubes (HNTs), and flame-retarding modified lignin (F-lignin) were compounded to fabricate the rGO-HNTs-(F-lignin) film. In the rGO-HNTs-(F-lignin) film, the F-lignin binds the rGO sheets and HNTs, enhancing the entanglement of HNTs and the interactions between HNTs and rGO sheets, and the macromolecular F-lignin also improves the ductility of the rGO-HNTs-(F-lignin) film, while the entangled HNTs conversely reinforce the F-lignin to prevent the F-lignin from fracture when the rGO-HNTs-(F-lignin) film is under stress, further increasing the ductility of the rGO-HNTs-(F-lignin) film. The HNTs and F-lignin promote each other to enhance the strengthening and toughening effect on the rGO-HNTs-(F-lignin)-film, and endowing the rGO-HNTs-(F-lignin)-film with the superior mechanical properties of the tensile strength of 634 ± 38 MPa, tensile fracture strain of 8.17 ± 0.59 %, and toughness of 25.35 ± 2.95 MJ/m3, respectively. The rGO-HNTs-(F-lignin) film also exhibits improved flame-retardant properties due to the high flame retardancy of HNTs and F-lignin. These excellent integrated properties of the rGO-HNTs-(F-lignin) film will promote its potential applications as structural materials.

C-undecylcalix[4]resorcinarene Langmuir-Blodgett/Porous Reduced Graphene Oxide Composite Film as a Electrochemical Sensor for the Determination of Tryptophan.

In this study, a composite film was developed for the electrochemical sensing of tryptophan (Trp). Porous reduced graphene oxide (PrGO) was utilized as the electron transfer layer, and a C-undecylcalix[4]resorcinarene Langmuir-Blodgett (CUCR-LB) film served as the molecular recognition layer. Atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy, scanning electron microscopy (SEM), and electrochemical experiments were employed to analyze the characteristics of the CUCR-LB/PrGO composite film. The electrochemical behavior of Trp on the CUCR-LB/PrGO composite film was investigated, revealing a Trp linear response range of 1.0 × 10-7 to 3.0 × 10-5 mol L-1 and a detection limit of 3.0 × 10-8 mol L-1. Furthermore, the developed electroanalytical method successfully determined Trp content in an amino acid injection sample. This study not only introduces a rapid and reliable electrochemical method for the determination of Trp but also presents a new strategy for constructing high-performance electrochemical sensing platforms.

Development and properties of wheat straw nano-holocellulose and reduced graphene oxide composite films for active packaging materials

The nano-holocellulose was obtained from wheat straw, and a series of composite films were prepared from the nano-holocellulose and reduced graphene oxide by vacuum filtration. The properties of the resultant rGO/nano-holocellulose films were researched, including morphology, XRD analysis, mechanical properties, UV-Vis transparency, contact angle, water vapor permeabilities, swelling properties, thermogravimetric analysis, and electrical conductivity. The results demonstrated that the tensile properties of the films were augmented by 639.8 %, as high as 88.70 MPa with the 8 % content of the rGO. The maximum UV transmittances of the 10 % rGO-Film in the far ultraviolet region, the middle ultraviolet region, and the near-ultraviolet region were 0.1 %, 0.4 %, and 2.1 %, respectively, which could blocked the penetration of ultraviolet light to a great extent. In addition, the hydrophilicity, water vapor permeability value, and swelling ratio of the composite films were reduced, and moreover, the composite films were endowed with the ability to conduct electricity. Compared with the 0 % rGO-Film, the contact angle of the 10 % rGO-Film was increased by about twice, and the water vapor permeability value was decreased by 10.7 %. Furthermore, 10 % rGO-Film exhibited an approximately 25-fold in conductivity compared to 1 % rGO-Film. Therefore, the nano-holocellulose based composite films have good application prospects in biodegradable packaging materials. • The composite film was prepared by nano-holocellulose and rGO. • The composite film was obtained by the vacuum filtration. • The tensile and UV resistance properties of the films were greatly enhanced by rGO. • The films were endowed with electrical conductivity by the rGO. • The composite films could be applied in packaging materials.

Poly L- methionine/Electrochemically Reduced Graphene Oxide Composite Film Modified Glassy Carbon Electrode for the Simultaneous Determination of 5-hydroxyindole Acetic Acid and Tyrosine

An effective electrochemical sensor based on “poly L- methionine/Electrochemically Reduced Graphene Oxide Composite Film Modified Glassy Carbon Electrode (poly(L-Met)/ERGO/GCE))” has been developed for the individual and simultaneous determination of 5-hydroxyindole acetic acid (5-HIAA) and tyrosine (Tyr). In clinical point of view, simultaneous determination of these analytes is very important and a sensor for the same is not reported yet. This sensor offers sensitive, reproducible and selective determination of 5-HIAA and Tyr. Experimental parameters for the effective determination of the analytes were optimized. Under optimized conditions, quantification of 5-HIAA is possible within the range 1.0 × 10−5 M to 8.0 × 10−7 M and for Tyr in two ranges, 1.0 × 10−5 M to 5.0 × 10−6 M and 7.0 × 10−5 M to 2.0 × 10−5 M. The limit of detection and limit of quantification obtained for 5-HIAA using poly(L-Met)/ERGO/GCE are 5.0 × 10−7 M and 8.0 × 10−7 M respectively, and for Tyr, 1.0 × 10−6 M and 5.0 × 10−6 M respectively. The sensor was successfully applied for the determination of both 5-HIAA and Tyr in artificial urine and blood serum samples.

Simultaneous voltammetric sensing of three DNA bases guanine, adenine and thymine at poly(L-arginine)-electrochemically reduced graphene oxide composite film modified glassy carbon electrode

Simultaneous voltammetric sensing of three DNA bases guanine, adenine and thymine at poly(L-arginine)-electrochemically reduced graphene oxide composite film modified glassy carbon electrode

Surface engineering of poly(methyl methacrylate)–reduced graphene oxide composite films by Au7+ ion irradiation for biomedical application

In this work, PMMA-reduced graphene oxide (rGO) films (PrGO) were prepared by solvent evaporation and further, swift heavy ions (100 MeV gold ion) irradiated on them by varying fluences viz. 1 × 1011, 5 × 1011 and 1 × 1012 ions/cm2 (referred as PrGO-111, PrGO-511, PrGO-112). There was a low angle peak shift of rGO and the reduction of crystallinity at higher fluences. On irradiation, the intensities of the vibrational modes of C–H bonding, hydroxyl, carboxyl groups of rGO and the band gap (36%) are reduced. The surface roughness (69%), pore size (∼10–24 μm), hemocompatibility and contact angle are enhanced on irradiation. The antibacterial efficiency and cell proliferation were augmented on PrGO-511 compared to the other films. The Au ion irradiation tailors surface roughness, contact angle, antibacterial activity and cell proliferation. Further, the atomic local bonding and surface roughness are correlated with the biological properties. Thus, the irradiated PrGO films could be an excellent candidate for applications in the biomedical field.

A Simple Approach towards Highly Dense Graphene Films for High Volumetric Performance Supercapacitors

AbstractAn interface self‐assembly followed by hydrothermal reduction method are proposed to obtain a tannic acid (TA)‐modified reduced graphene oxide composite film (|TA/RGO|). This unique method endows |TA/RGO| with several advantages: (1) TA is adopted as a redox‐active spacer between adjacent interlayers for enlarging the ion‐accessible area and contributing to pseudocapacitance; (2) due to the intensive pressure exerted by the sandwich‐like device during the hydrothermal reduction process, appropriate expansion and a relatively flat layered structure are achieved which will facilitate the ion transport. As a result, the |TA/RGO| film shows an ultrahigh volumetric performance of 701 F cm−3 with a high density of 1.91 g cm−3 using a three‐electrode system. When assembled into a symmetric supercapacitor, |TA/RGO| film delivers a high volumetric capacitance of 244.8 F cm−3 and a high capacitance retention of 100 % after 5000 cycles at the current density of 2 A g−1, showing a great potential for large‐scale application.

Microporous micro-arc oxidation/bis-[3-triethoxysilylpropyl]tetrasulfide/graphene composite film with improved corrosion protection properties on aluminum alloy

Micro-arc oxidation, bis-[3-triethoxysilopropyl] tetrasulfide and reduced graphene oxide composite film was prepared on AA 6061 using a combination of micro-arc oxidation and self-assembly. The morphological、chemical characteristics、corrosion resistance and film formation mechanism of the composite film were studied. The results showed that a complete and dense composite film was formed on the surface of aluminum alloy, which may be due to the formation of Al–O–Si, Si–O–Si and Si–O–C chemical bonds on aluminum alloy by self-assembly doping technology. The composite film effectively prevented the corrosive medium from contacting the aluminum alloy, thus protecting the aluminum alloy substrate.

3D porous graphene composite film embedded by Ni/NiO nanoparticles as freestanding electrodes for efficient energy storage devices

A 3D porous graphene composite film containing Ni/NiO hybrid nanoparticles (Ni/NiO NPs) is prepared by combining electrophoresis deposition and thermal H2 annealing techniques. The Ni/NiO NPs with a mean diameter of 45 nm are uniformly embedded on both the exterior and interior surfaces of reduced graphene, forming a 3D porous reduced graphene oxide composite film (Ni/NiO rGO). The insertion of Ni/NiO NPs into rGO greatly improves the electric conductivity and charge storage capability of the resultant Ni/NiO rGO film. By directly using it as freestanding electrodes, the fabricated lithium-ion battery and supercapacitor respectively exhibited high capacities of 758 mAh g−1@ 0.2 A g−1 and 430.8 F g−1@0.5 A g−1, an increase of 82.3-fold and 20.2-fold compared to the pure rGO electrode-based counterparts under the same condition.

Individual and simultaneous voltammetric sensing of norepinephrine and tyramine based on poly(L-arginine)/reduced graphene oxide composite film modified glassy carbon electrode

Abstract This article details a voltammetric sensor for the simultaneous determination of norepinephrine (NE) and tyramine (TYM) using poly (L-arginine) and reduced graphene oxide composite film modified glassy carbon electrode (p(L-Arg)/ERGO/GCE). Under optimized conditions, the sensor displayed well separated and resolved peaks for the electro oxidation of NE and TYM. Quantification of these analytes were achieved with wide linear ranges and low detection limits both individually and simultaneously. The mechanistic parameters have been clearly addressed. The efficacy of the proposed sensor has been proved by the successful application of the method in physiological fluids.

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.

Ultratough reduced graphene oxide composite films synergistically toughened and reinforced by polydopamine wrapped carbon nanotubes

Nacre like graphene based composite films (GCFs) have been developed over the last decade. Although the progress in ultrastrong GCFs is remarkable, fabricating GCFs with excellent integrated properties of strength, flexibility, and toughness still remains a challenge. Here, a ternary GCF of reduced graphene oxide (rGO), polydopamine (PDA) and multi-walled carbon nanotubes (MWCNTs) was developed. The MWCNTs were modified by PDA to form PDA@MWCNTs which were then compounded with GO to fabricate the rGO-PDA@MWCNT films by evaporation-induced assembly and chemical reduction. The preparation was simple, cheap and environmentally-friendly. The PDA increased the dispersion of MWCNTs in the rGO-PDA@MWCNT films, crosslinked the rGO sheets, and enhanced the entanglement of MWCNTs and the interactions between MWCNTs and rGO sheets. Benefiting from the synergistic effect of PDA and MWCNTs, the rGO-PDA@MWCNT films exhibited excellent integrated properties by increasing strength, tensile fracture strain and toughness to 579 ± 35 MPa, 12.03 ± 0.56%, and 34.03 ± 1.60 MJ/m3, which were 2.26, 2.02 and 4.94 times that of pure rGO films, respectively. The rGO-PDA@MWCNT films also exhibited a high conductivity of 612 ± 68 S/cm and excellent structural stability under extreme environments. These excellent integrated properties of the rGO-PDA@MWCNT films will promote their applications in aerospace engineering, flexible electrical devices and artificial muscle.

Facile preparation of binder–free electrode for electrochemical capacitors based on reduced graphene oxide composite film

Binder-free electrode based on reduced graphene oxide (rGO) is attracting attention for electrochemical capacitors. Here the binder-free electrodes have been fabricated by activating the composite films of GO and carbonized cornstalk-cores. In the composites, the rGO sheets are found to be tightly adhered to the activated bio‑carbon which is intercalated between the rGO sheets to prevent them from stacking. Moreover, the influences of the mass ratios of GO to bio‑carbon on the electrochemical performance have been systematically investigated. The optimal binder-free electrode (rGO/ACCS1/1) prepared from the composite films with 1:1 mass ratio of GO to bio‑carbon exhibits a specific capacitance as high as 278Fg−1 at scan rate of 1mVs−1 and shows excellent stability in 6M KOH electrolyte. Furthermore, the optimal electrode can retain 47.8% of the initial specific capacitance even at current density of 100Ag−1, indicating a fast charge-discharge capability. This work provides a simple method to prepare binder-free composite electrodes by introducing renewable and inexpensive biomass based carbon into activated rGO films.

Flexible cellulose nanofibril/pristine graphene nanocomposite films with high electrical conductivity

Cellulose nanofibrils extracted from wood are natural polymer nanomaterials with high specific surface area, low density, high strength, and high elastic modulus. However, they are insulating materials and cannot be directly used in the electronic devices. Herein, pristine graphene (PG) exfoliated by triethanolamine was used to composite with TEMPO-oxidized cellulose nanofibril (TOCN) to prepare the conductive nanocomposite films in aqueous system. As a reference, the graphene oxide (GO) and reduced graphene oxide (RGO) were also composited with TOCN to prepared the TOCN−GO and TOCN−RGO composite films. The maximum electrical conductivity of the TOCN−PG film was 568 S/cm with 20 wt% PG, achieving great enhancement than the TOCN film with insulation. It was also much higher than the TOCN−GO films (3.44 × 10−11 S/cm) and about 185 times more than TOCN−RGO composite films (3.06 S/cm). Moreover, the TOCN−PG composites containing 10 wt% PG exhibited excellent tensile strength, elastic modulus and the elongation at break of 389 MPa, 8.0 GPa and about 20%, respectively, much higher than those of the neat TOCN film.

One‐Step Synthesis of Vacancy‐Rich MnO2−x/Reduced Graphene Oxide Composite Film for High Electrochemical Performance

AbstractHigh electrochemical performance is important to achieve practical application of energy storage devices. It has been found recently that it is hard to achieve high capacity and high stability simultaneously using a single electrode material. Thus, constructing composite electrode materials which can combine the advantages of different materials together is an efficient approach to improve the electrochemical properties. In this work, we have built a vacancy‐rich MnO2−x/reduced graphene oxide (rGO) composite film through a facile one‐step route. In the synthesis process, GO nanosheets were reduced into rGO to improve the electronic conductivity, while Mn2+ was oxidized to MnO2 with vacancies. The obtained vacancy‐rich MnO2−x/rGO composite showed a superior electrochemical performance: The specific capacitance reached 675.5 F/g at a current density of 0.5 A/g and the material demonstrated high capacitance retention (96.1 % after 10000 cycles). Besides, the symmetric electrochemical capacitor based on the vacancy‐rich MnO2−x/rGO composite electrode can achieve a high energy density (8.42 mWh/cm3) and power density (3.78 W/cm3) as well as excellent stability.

A novel electrochemical sensor based on poly(p-aminobenzene sulfonic acid)-reduced graphene oxide composite film for the sensitive and selective detection of levofloxacin in human urine

To develop the sensitive and selective levofloxacin sensors with simple preparation process, the novel poly(p-aminobenzene sulfonic acid)-reduced graphene oxide (poly(p-ABSA)-rGO) composite film-based electrochemical sensor was facilely and rapidly prepared by one-step electrochemical method without the expensive and troublesome electrode modification procedure. The poly(p-ABSA)-rGO composite film was found to possess remarkable catalytic activity on the oxidation of levofloxacin. Electrocatalytic performance of the as-prepared sensor could be dramatically improved by optimizing the synthesis conditions of composite film. Based on the synergetic effect of organic conductive polymer poly(p-ABSA) and rGO, the proposed sensor exhibited excellent electrocatalytic activity of levofloxacin, high sensitivity, low detection limit (0.12 μM), wide linear range and excellent selectivity. Further, the fabricated sensor was successfully applied onto the determination of levofloxacin in real human urine samples and showed good reliability for real samples assay. Based on the simple construction process and excellent electrocatalytic performance, the proposed poly(p-ABSA)-rGO film-based sensor demonstrated the potential for the extensive applications on electroanalysis and bioelectrocatalysis.

Large‐Area Reduced Graphene Oxide Composite Films for Flexible Asymmetric Sandwich and Microsized Supercapacitors

AbstractAsymmetric supercapacitors have attracted tremendous attention in energy storage devices since they have an enhanced energy density in comparison with symmetric supercapacitor devices. Furthermore, the development of diverse and flexible electronic devices requires the asymmetric supercapacitor devices to be flexible and in various configurations. However, it is still a challenge to develop a universal strategy to obtain both capacitive and Faradic electrodes with various architectures. Herein, a spontaneously reducing/assembling strategy in an alkaline condition is developed to fabricate large‐area reduced graphene oxide (RGO) and RGO–metal oxide/hydroxide composite films or microsized structures. As a proof of concept, the large‐area pure RGO and RGO/Mn3O4 composite films with porous structure and superior mechanical property are achieved by such strategy. These RGO‐based films can directly serve as the anodes and cathodes of the flexible asymmetric film supercapacitors. Furthermore, the interdigital RGO and RGO/Mn3O4 patterns are also obtained via a selectively reducing/assembling process to achieve the asymmetric microsized supercapacitors. These asymmetric supercapacitors with different configurations possess good electrochemical performance and excellent flexibility. Therefore, such reducing and assembling strategy provides a route to achieve large‐area RGO‐based films and microsized structures for the applications in the various fields such as energy storage and photocatalysis.

Reduced graphene oxide-cyclodextrin-chitosan electrochemical sensor: Effective and simultaneous determination of o- and p-nitrophenols

A novel electrochemical sensor based on cyclodextrin and chitosan-functionalized reduced graphene oxide composite film was designed and prepared to detect o- and p-nitrophenols simultaneously. Apart from the synergistic effect of large specific surface area of reduced graphene oxide (RGO), the adsorption of nitrophenols (NPhs) through electrostatic interaction benefited from large quantities of host–guest recognition sites on cyclodextrin (CD) and abundant functional groups on chitosan. By taking advantage of the salient features of RGO, CDs, and chitosan, p-nitrophenol (p-NPh) and o-nitrophenol (o-NPh) can be determined simultaneously based on their nitroaromatic/hydroxylamine redox reactions. Under the optimized experimental conditions, a wide linear range was obtained over o-NPh concentration from 0.12μM to 0.28μM and 5μM to 40μM with a detection limit of 0.018μM (S/N=3) as well as p-NPh concentration from 0.06μM to 0.16μM and 5μM to 40μM along with a detection limit of 0.016μM (S/N=3). In addition, the newly developed reduced graphene oxide-cyclodextrin-chitosan (RGO-CD-CS) sensor displayed high accuracy, satisfactory reproducibility, good stability, and adequate efficiency in simultaneously detecting o-NPh and p-NPh in aqueous samples.

Preparation of porous polyimide/in-situreduced graphene oxide composite films for electromagnetic interference shielding

Herein we report an easy and efficient approach to prepare lightweight porous polyimide (PI)/reduced graphene oxide (RGO) composite films. First, porous poly (amic acid) (PAA)/graphene oxide (GO) composite films were prepared via non-solvent induced phase separation (NIPS) process. Afterwards PAA was converted into PI through thermal imidization and simultaneously GO dispersed in PAA matrix was in situ thermally reduced to RGO. The GO undergoing the same thermal treatment process as thermal imidization was characterized with thermogravimetric analysis, Raman spectra, X-ray photoelectron spectroscopy and X-ray diffraction to demonstrate that GO was in situ reduced during thermal imidization process. The resultant porous PI/RGO composite film (500-µm thickness), which was prepared from pristine PAA/GO composite with 8 wt% GO, exhibited effective electrical conductivity of 0.015 S m−1 and excellent specific shielding efficiency value of 693 dB cm2 g−1. In addition, the thermal stability of the porous PI/RGO composite films was also dramatically enhanced. Compared with that of porous PI film, the 5% weight loss temperature of the composite film mentioned above was improved from 525°C to 538°C. Moreover, tensile test showed that the composite film mentioned above possessed a tensile strength of 6.97 MPa and Young's modulus of 545 MPa, respectively. Copyright © 2016 John Wiley & Sons, Ltd.