Nafion Graphene Research Articles

Nonenzymatic Glucose Biosensor Based on NiNPs/Nafion/Graphene Film for Direct Glucose Determination in Human Serum

This study describes a type of novel nickel nanoparticles (NiNPs) decorated on Nafion-graphene composite film by using the electrochemical deposition method. It was used to fabricate electrochemical biosensors for sensitive nonenzymatic glucose detection. Compared with the Nafion–graphene film and NiNPs-modified glassy carbon electrode (NiNPs-GCE), the NiNPs/Nafion/graphene/GCE showed the best electrocatalytic activity towards glucose oxidation in alkaline medium. The NiNPs/Nafion/graphene/GCE at an applied potential of [Formula: see text]0.55[Formula: see text]V in a linear range of 1–200[Formula: see text][Formula: see text]M presented a high sensitivity of 3437.25[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text] with coefficient of correlation [Formula: see text]; and in a linear range of 200–10[Formula: see text]800[Formula: see text][Formula: see text]M it performed the best sensitivity of 2848.6[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text] with coefficient of correlation [Formula: see text] towards glucose oxidation. For a concentration up to 200[Formula: see text][Formula: see text]M, a linear range was obtained with a limit of detection of 0.6[Formula: see text][Formula: see text]M (signal to noise [Formula: see text] 3) and as much as 10[Formula: see text]800[Formula: see text][Formula: see text]M with a limit of detection of 0.82[Formula: see text][Formula: see text]M (signal to noise [Formula: see text] 3). The time of responses was about 1–1.5[Formula: see text]s with the addition of 0.1–1[Formula: see text]mM glucose. In addition, NiNPs/Nafion/graphene/GCE also has a high anti-interference ability toward common oxidative interfering species, such as uric acid, ascorbic acid and dopamine. More importantly, NiNPs/Nafion/graphene/GCE was successfully used for the determination of glucose concentration in human serum samples in comparison with a local hospital. The NiNPs/Nafion/graphene/GCE exhibited high sensitivity, low working potential, good stability, excellent electrical properties, enhanced selectivity and fast amperometric responses to glucose oxidation. Thus, as a nonenzymatic sensor, it is promising for future glucose determination development.

Complexation-Based Detection of Nickel(II) at a Graphene-Chelate Probe in the Presence of Cobalt and Zinc by Adsorptive Stripping Voltammetry.

The adsorptive stripping voltammetric detection of nickel and cobalt in water samples at metal film electrodes has been extensively studied. In this work, a novel, environmentally friendly, metal-free electrochemical probe was constructed for the ultra-trace determination of Ni2+ in water samples by Adsorptive Cathodic Stripping Voltammetry (AdCSV). The electrochemical platform is based on the adsorptive accumulation of Ni2+ ions directly onto a glassy carbon electrode (GCE) modified with dimethylglyoxime (DMG) as chelating agent and a Nafion-graphene (NGr) nanocomposite to enhance electrode sensitivity. The nafion-graphene dimethylglyoxime modified glassy carbon electrode (NGr-DMG-GCE) shows superior detection capabilities as a result of the improved surface-area-to-volume ratio and enhanced electron transfer kinetics following the incorporation of single layer graphene, while limiting the toxic effects of the sensor by removal of the more common mercury, bismuth and lead films. Furthermore, for the first time the NGr-DMG-GCE, in the presence of common interfering metal ions of Co2+ and Zn2+ demonstrates good selectivity and preferential binding towards the detection of Ni2+ in water samples. Structural and morphological characterisation of the synthesised single layer graphene sheets was conducted by Raman spectrometry, HRTEM and HRSEM analysis. The instrumental parameters associated with the electrochemical response, including accumulation potential and accumulation time were investigated and optimised in addition to the influence of DMG and graphene concentrations. The NGr-DMG-GCE demonstrated well resolved, reproducible peaks, with RSD (%) below 5% and a detection limit of 1.5 µg L−1 for Ni2+ reduction at an accumulation time of 120 s. The prepared electrochemical sensor exhibited good detection and quantitation towards Ni2+ detection in tap water samples, well below 0.1 mg L−1 set by the WHO and EPA standards. This is comparable to the South African drinking water guidelines of 0.15 mg L−1.

ChemInform Abstract: Ligand‐Free C—C and C—N Cross‐Couplings with Pd/Nf‐G Nanocomposite.

Abstract The catalytic activity of electrochemical deposited Pd nanoparticles on nafion–graphene support was examined for Buchwald–Hartwig amination reaction and Heck coupling reaction. The developed protocol is very efficient and ecofriendly, providing excellent product yield. The Pd/Nf-G catalyst can be used up to four cycles with slight decrease in catalytic activity.

Ligand-free C–C and C–N cross-couplings with Pd/Nf-G nanocomposite

The catalytic activity of electrochemical deposited Pd nanoparticles on nafion–graphene support was examined for Buchwald–Hartwig amination reaction and Heck coupling reaction. The developed protocol is very efficient and ecofriendly, providing excellent product yield. The Pd/Nf-G catalyst can be used up to four cycles with slight decrease in catalytic activity.

One step electrochemical synthesis of bimetallic PdAu supported on nafion–graphene ribbon film for ethanol electrooxidation

A nafion–graphene ribbon (Nf–GR) supported bimetallic PdAu nanoparticles (PdAu/Nf–GR) catalyst was prepared by electrochemical codeposition of Pd and Au at constant potential. The prepared catalyst was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The average particle size of PdAu nanoparticles (NPs) determined from XRD was 3.5nm. The electrocatalytic activity of the PdAu/Nf–GR catalyst was examined by cyclic voltametry. It was observed that the as prepared catalyst showed efficient activity and good stability for ethanol electrooxidation in alkaline medium.

ChemInform Abstract: Electrochemical Synthesis of Copper Nanoparticles on Nafion—Graphene Nanoribbons and Its Application for the Synthesis of Diaryl Ethers.

AbstractThe title catalyst is successfully employed for the Ullmann type coupling of phenols with aromatic halides to produce diaryl ethers in generally good yields.

Electrochemical synthesis of copper nanoparticles on nafion–graphene nanoribbons and its application for the synthesis of diaryl ethers

Electrochemical synthesis of copper nanoparticles on nafion–graphene nanoribbons support for the synthesis of diaryl ethers via Ullmann type coupling is reported. The catalyst showed excellent performance for C–O cross coupling reactions under ligand free condition. The catalyst was characterized by various techniques such as SEM, TEM, XRD, EDX, BET, TGA, and UV spectrophotometry. It was recycled several times without significant loss in its catalytic activity.

ChemInform Abstract: Electrochemical Synthesis and Characterization of Palladium Nanoparticles on Nafion—Graphene Support and Its Application for Suzuki Coupling Reaction.

AbstractThe reusable catalyst (5 times without significant loss of efficiency) is synthesized by electrochemical deposition.

Sensitive HIV-1 detection in a homogeneous solution based on an electrochemical molecular beacon coupled with a nafion–graphene composite film modified screen-printed carbon electrode

A novel electrochemical sensing assay for sensitive determination of HIV-1 in a homogeneous solution has been developed using an electrochemical molecular beacon combined with a nafion–graphene composite film modified screen-printed carbon electrode (nafion–graphene/SPCE). The electrochemical molecular beacon (CAs-MB), comprising a special recognition sequence for the conserved region of the HIV-1 gag gene and a pair of carminic acid molecules as a marker, can indicate the presence of the HIV-1 target by its on/off electrochemical signal behavior. It is suitable for direct, electrochemical determination of HIV-1, thereby simplifying the detection procedure and improving the signal-to-noise (S/N) ratio. To further improve the sensitivity, the nafion–graphene/SPCE was used to monitor changes in the CAs-MB, which has notable advantages, such as being ultrasensitive, inexpensive, and disposable. Under optimized conditions, the peak currents showed a linear relationship with the logarithm of target oligonucleotide concentrations ranging from 40nM to 2.56μM, with a detection limit of 5nM (S/N=3). This sensing assay also displays a good stability, with a recovery of 88–106.8% and RSD<7% (n=5) in real serum samples. This work may lead to the development of an effective method for early point-of-care diagnosis of HIV-1 infection.

The Suzuki-Miyaura Coupling with Pd NPs Supported on Nafion-Graphene

Key words palladium nanoparticles - nafion–graphene support - Suzuki–Miyaura coupling

Square-wave stripping voltammetric determination of caffeic acid on electrochemically reduced graphene oxide–Nafion composite film

An electrochemical sensor composed of Nafion–graphene nanocomposite film for the voltammetric determination of caffeic acid (CA) was studied. A Nafion graphene oxide-modified glassy carbon electrode was fabricated by a simple drop-casting method and then graphene oxide was electrochemically reduced over the glassy carbon electrode. The electrochemical analysis method was based on the adsorption of caffeic acid on Nafion/ER-GO/GCE and then the oxidation of CA during the stripping step. The resulting electrode showed an excellent electrocatalytical response to the oxidation of caffeic acid (CA). The electrochemistry of caffeic acid on Nafion/ER-GO modified glassy carbon electrodes (GCEs) were studied by cyclic voltammetry and square-wave adsorption stripping voltammetry (SW-AdSV). At optimized test conditions, the calibration curve for CA showed two linear segments: the first linear segment increased from 0.1 to 1.5 and second linear segment increased up to 10µM. The detection limit was determined as 9.1×10−8molL−1 using SW-AdSV. Finally, the proposed method was successfully used to determine CA in white wine samples.

Electrochemical Deposition of Highly Dispersed Palladium Nanoparticles on Nafion‐Graphene Film in Presence of Ferrous Ions for Ethanol Electrooxidation

AbstractAn efficient method was developed to produce highly dispersed Pd nano particles (NPs), supported on Nafion‐graphene film by electrochemical deposition at constant potential in presence of ferrous ions. The Fe2+ ions govern the size, shape and morphology of Pd NPs. The as‐prepared catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD). It was obeserved from TEM that the mean diameter of electrodeposited Pd NPs was 6.4 ± 1.3 nm with narrow diameter range from 4 to 10 nm. The electrocatalytic performance of the Pd NPs deposited on Nafion‐graphene (Nf‐G) catalyst was studied by cyclic voltametry (CV) and chronoamperometric measurements. The highly dispersed Pd NPs on Nf‐G film were obtained in presence of Fe2+ ions. This alters electrochemical active surface area and hence catalytic activity of Pd NPs. The prepared Pd/Nf‐G catalyst exhibit highest tolerance to the intermediate poisoning species (ratio If/Ib = 2.2). The as‐obtained catalyst shows an efficient electrocatalytic activity and good stability for ethanol oxidation in alkaline medium.

Electrochemical synthesis and characterization of palladium nanoparticles on nafion–graphene support and its application for Suzuki coupling reaction

The electrochemically deposited palladium nanoparticles on nafion–graphene support showed an excellent catalytic activity for Suzuki coupling reactions. The as obtained catalyst was characterized by SEM, TEM, EDAX, XRD, and TGA. The particle size of palladium nanoparticles (Pd NPs) determined from TEM was in the range of 4–12 nm. The mean diameter of Pd NPs was found to be 8.1 ± 1.9 nm. The recyclability of the catalyst was examined and it did not show any significant loss of catalytic activity for five consecutive cycles.

Bimetallic PtPd nanoparticles on Nafion–graphene film as catalyst for ethanol electro-oxidation

Download options Please wait... Additions and corrections Addition HTM (3K) Article information DOI https://doi.org/10.1039/C2JM16916A Article type Paper Submitted 30 Dec 2011 Accepted 12 Feb 2012 First published 14 Mar 2012 Download Citation J. Mater. Chem., 2012,22, 8057-8062 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Bimetallic PtPd nanoparticles on Nafion–graphene film as catalyst for ethanol electro-oxidation X. Yang, Q. Yang, J. Xu and C. Lee, J. Mater. Chem., 2012, 22, 8057 DOI: 10.1039/C2JM16916A To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Xia Yang Qingdan Yang Jun Xu Chun-Sing Lee

In situ synthesis of palladium nanoparticle–graphene nanohybrids and their application in nonenzymatic glucose biosensors

A nonenzymatic electrochemical biosensor was developed for the detection of glucose based on an electrode modified with palladium nanoparticles (PdNPs)-functioned graphene (nafion–graphene). The palladium nanoparticle–graphene nanohybrids were synthesized using an in situ reduction process. Nafion–graphene was first assembled onto an electrode to chemically adsorb Pd 2+. And Pd 2+ was subsequently reduced by hydrazine hydrate to form PdNPs in situ. Such a PdNPs–graphene nanohybrids-based electrode shows a very high electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium. The proposed biosensor can be applied to the quantification of glucose with a wide linear range covering from 10 μM to 5 mM ( R = 0.998) with a low detection limit of 1 μM. The experiment results also showed that the sensor exhibits good reproducibility and long-term stability, as well as high selectivity with no interference from other potential competing species.

Stable Nafion-functionalized graphene dispersions for transparent conductingfilms

Nafion was used for the first time to aid in preparing stable graphene dispersions in mixedwater/ethanol (1:1) solvents via the reduction of graphite oxide using hydrazine. The dispersionwas characterized by ultraviolet–visible (UV–vis) spectra, transmission electronmicroscopy, zeta potential analysis, etc. It was found that for Nafion-to-grapheneratios higher than 5:1, graphene solutions with concentrations up to 1 mg ml−1 and stabilities of over three months were obtained. It was proposed that the Nafionadsorbed onto the graphene by the hydrophobic interaction of its fluoro-backboneswith the graphene layer and imparted stability by an electrosteric mechanism.Furthermore, transparent and conductive films were prepared using these highlystable Nafion-stabilized graphene dispersions. The prepared Nafion–graphene filmspossess smooth and homogeneous surfaces and the sheet resistance was as low as 30 kΩ/sq for a transmittance of 80% at 550 nm, which was much lower than for other graphene filmsobtained by chemical reduction. X-ray photoelectron spectroscopy and Raman spectroscopyconfirmed the p-doping of the graphene by Nafion. It was expected that this p-doping effect, aswell as the high dispersing ability of Nafion for graphene and the connection of thesp2 domains by residual Nafion combined to produce good properties of the Nafion–graphenefilms.

Nafion–graphene nanocomposite film as enhanced sensing platform for ultrasensitive determination of cadmium

In this work, an ultrasensitive platform for the detection of cadmium (Cd 2+) combining the nafion–graphene nanocomposite film with differential pulse anodic stripping voltammetry (DPASV) analysis was presented. It is found that this sensing platform exhibits enhanced response to the determination of the Cd 2+ and has been used to determine the Cd 2+ in real sample with good recovery.