Multi-walled Carbon Nanotubes Hybrid Materials Research Articles

Electrochemical determination of 4-nitrophenol using functionalized graphene oxide/functionalized multi-walled carbon nanotubes hybrid material modified glassy carbon electrode

Herein, a novel carboxylated multi-walled carbon nanotubes-carboxylated graphene oxide coated glassy carbon electrode (f-MWCNTs/f-GO/GCE) was prepared for electrochemical determination of 4-nitropehenol (4-NP). The sensor was characterized using fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), raman spectroscopy, and powder x-ray diffraction (XRD). Electrochmical experiments were performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry. The resulting f-MWCNTs/f-GO/GCE could be performed for quick, sensitive, and selective determination of 4-NP in the presence of other electroactive compounds. 4-NP was electrochemically detected depending on the reduction of 4-NP at −0.65 V potential using amperometric method. Under the optimum condutions, the sensor showed excellent response to the determination of 4-NP with three linear detection ranges from 0.018 to 700 µM. The sensor exhibited extremely low limit of detection (5.4 nM). Also, the fabricated sensor was used for detection of 4-NP in different water samples.

Rapid and Sensitive Detection of Isoproturon Via an Electrochemical Sensor Based on Highly Water-Dispersed Carbon Hybrid Material

Isoproturon (ISO), an herbicide belonging to the phenyl urea family, is extensively used in modern agriculture to guarantee a bumper harvest. However, it has been evidenced that the ISO has heavy toxicity to the liver system and appears to be a tumor promoter. It is therefore urgent to develop sensitive and selective methods to screen its presence in food resources to meet the ever-increasing pollution restrictions. In this work, an electrochemical sensor based on graphene oxide–modified multi-walled carbon nanotubes hybrid material was firstly developed for the rapid and sensitive detection of ISO via square wave voltammetry (SWV). Under optimized experimental conditions, the sensor exhibits a relatively wide linear range from 0.30 to 15.0 μmol L−1, a low limit of detection (LOD) of 0.10 μmol L−1, as well as good repeatability, high reproducibility, excellent selectivity, and long-term stability. The sensor has also been successfully employed in various real samples such as rice field water, tomato, and lettuce analyses. The obtained recoveries are in the range of 97.33–105.0% with low relative standard deviation (less than 2.5%), which is very close to the results of the high-performance liquid chromatography (HPLC), showing the proposed electrochemical sensor has great potential in practical applications.

Preparation and characterization of poly (3-hexylthiophene) / carbon nanotubes hybrid material via in-situ click chemistry

Abstract The poly(3-hexylthiophene) - multiwalled carbon nanotube hybrid material (P3HT-MWCNT) was successfully prepared in the Cu(I)/DBU catalyst system via in-situ click reaction. The properties of P3HT-MWCNT were measured by FTIR, 1H NMR, UV-vis, XRD, TEM, SEM . The fluorescence spectrum of P3HT-MWCNT proved the covalent bond between P3HT and MWCNT, and P3HT could be coated on the surface of MWCNT. Compared with the physical blends of P3HT and MWCNT, P3HT-MWCNT prepared by click chemistry exhibited better thermal stability and a higher melting point of 243.2 °C. TG results also indicated that P3HT content of P3HT-MWCNT was 21.4%. It was expected to prepare novel organic-inorganic donor-acceptor hybrid material with good solubility, optical and thermal stability, which may be a promising material applied in preparation of organic photoelectron in the future.

Facile preparation of asymmetric phthalocyanine/multi-walled carbon nanotube hybrid material by in situ click chemistry

The asymmetrical zinc phthalocyanine–multiwalled carbon nanotube hybrid material (aZnPc–MWCNT) were successfully prepared by in situ click chemistry of 4-(m-tolyloxygen)-5-nitrophthalonitrile and 4-azide-phthalonitrile modified MWCNT precursors in the Cu(I)/DBU catalyst system. In situ click chemistry reactions and covalent bonds between aZnPc and MWCNT were confirmed by FT-IR, UV–Vis and fluorescence spectra. The aZnPc–MWCNT red-shifted 12–690 nm compared with pristine ZnPc. The microstructure and morphology of aZnPc–MWCNT were investigated by TEM, SEM and AFM. The solubility of aZnPc–MWCNT could be significantly improved. After the ZnPc were uniformly distributed on the surface of MWCNTs, the aggregation of aZnPc–MWCNT was significantly reduced. The thermal degradation temperature of aZnPc–MWCNT was 72.8 °C higher than that of pristine ZnPc. TG results also indicated that the ZnPc content of aZnPc–MWCNT is 14.4%. It is expected that novel organic–inorganic donor–acceptor hybrid material possessing good solubility, optical and thermal stability properties would be obtained, and new materials for the preparation of organic electronic devices should be provided.

Synthesis, characterization and application in the water purification of the multi-walled carbon nanotubes hybrid material

In this study, we synthesized Multi Walled Carbon Nanotubes-Schiff base hybrid material (HB) and characterized by the SEM, TEM, RAMAN, FTIR, Uv-vis, EDX, TGA and XRD methods. We oxidized the O-MWCNTs and obtained the carboxyl and hydroxyl groups on the edge of the carbon nanotube. The silane derivative of the O-MWCNTs was obtained from the(3-aminopropyl)trimethoxysilane and O-MWCNTs in toluene solution. Hybrid material was obtained from the 3,5-diiodosalicylaldehyde and APTES–MWCNTs. This hybrid material was used for purification the drinking water from the heavy metals nickel and cadmium by the batch method. At pH= 7, hybrid material reached the maximum adsorption capacity.

Electromechanical Behavior of Chemically Reduced Graphene Oxide and Multi-walled Carbon Nanotube Hybrid Material.

In this paper, we propose strain-sensitive thin films based on chemically reduced graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) without adding any further surfactants. In spite of the insulating properties of the thin-film-based GO due to the presence functional groups such as hydroxyl, epoxy, and carbonyl groups in its atomic structure, a significant enhancement of the film conductivity was reached by chemical reduction with hydro-iodic acid. By optimizing the MWCNT content, a significant improvement of electrical and mechanical thin film sensitivity is realized. The optical properties and the morphology of the prepared thin films were studied using ultraviolet-visible spectroscopy (UV-Vis) and scanning electron microscope (SEM). The UV-Vis spectra showed the ability to tune the band gap of the GO by changing the MWCNT content, whereas the SEM indicated that the MWCNTs were well dissolved and coated by the GO. Investigations of the piezoresistive properties of the hybrid nanocomposite material under mechanical load show a linear trend between the electrical resistance and the applied strain. A relatively high gauge factor of 8.5 is reached compared to the commercial metallic strain gauges. The self-assembled hybrid films exhibit outstanding properties in electric conductivity, mechanical strength, and strain sensitivity, which provide a high potential for use in strain-sensing applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-015-1216-5) contains supplementary material, which is available to authorized users.

A role of nanotube dangling pyrrole and oxygen functions in the electrochemical synthesis of polypyrrole/MWCNTs hybrid materials

The effect of the functionalization of multi-walled carbon nanotubes (MWCNTs) on the process of electrochemical co-deposition of MWCNTs and polypyrrole (PPy), as well as the morphology of obtained composites have been demonstrated. As the nanotube components of the hybrids, three types of MWCNT were used, namely c-CVD derived (pristine) MWCNTs, their oxidized counterparts MWCNT-Ox and pyrrole-modified MWCNT-Py. The stability of pristine and functionalized MWCNTs (f-MWCNT) dispersions in tetrahydrofuran and water was studied together with the description of the process of formation PPy/(f-)MWCNT hybrid materials via electrochemical co-deposition. The structural and morphological properties of the hybrids were characterized by Raman spectroscopy, scanning electron microscopy and atomic force microscopy revealing substantial differences among hybrid materials in their surface morphology and the influence of MWCNT functionalization on the orientation of growing PPy chains.

Preparation of aluminum oxide-coated carbon nanotubes and the properties of composite epoxy coatings research

Multiwalled carbon nanotubes (MWCNTs) were acidized to get MWCNTs-COOH; the aluminum oxide (Al2O3)-coated MWCNTs hybrid material were prepared by sol–gel method and the result of cladding was verified using x-ray diffraction and scanning electron microscopy. Silane-coupling agent (KH560) was used to modify the hybrid materials. Composite coating with different concentrations of MWCNTs and Al2O3-coated MWCNTs was prepared. The wear resistance of the composite coating was tested by wear tester. The impedance performance and flexibility of Al2O3-coated MWCNTs/epoxy (2 wt%) and MWCNTs/epoxy (2 wt%, composite coating containing 2 wt% nanometer powder) were measured by the electrochemical workstation and mechanical testing equipment (MTS). The results show that the corrosion resistance and wear resistance of the Al2O3-coated MWCNTs/epoxy composite coating have some improvement compared with MWCNTs/epoxy, but a reduction in the flexibility of the Al2O3-coated MWCNTs/epoxy (2 wt%) composite coating.

RETRACTED ARTICLE: Application of Polypropylene Amine Dendrimers (POPAM)-Grafted MWCNTs Hybrid Materials as a New Sorbent for Solid-Phase Extraction and Trace Determination of Gold(III) and Palladium(II) in Food and Environmental Samples

A new method which utilizes a polypropylene amine dendrimers (POPAM)-grafted multi-walled carbon nanotubes (MWCNTs) hybrid materials as an effective sorbent in solid-phase extraction has been developed for separation and preconcentration of Au(III) and Pd(II) trace levels in food, water and soil samples. The optimum experimental conditions such as pH, flow rates, type, concentration, and volume of the eluent for elution of gold and palladium ions, breakthrough volume, and effect of potentially interfering ions on separation and determination of these noble metals were investigated. The extraction recoveries for the mentioned noble metals were greater than 98 % and the limits of detection were 0.08 and 0.12 ng mL−1 for gold and palladium, respectively. The relative standard deviations of the method were less than 4 % for eight separate column experiments for determination of 5.0 μg of gold and palladium ions. The adsorption capacity of the modified MWCNT was 92 mg g−1 for gold and 74 mg g−1 for palladium on POPAM-grafted MWCNTs. Validation of the suggested method was performed by analyzing certified reference materials. Finally, the proposed method was applied for determination of gold(III) and palladium(II) in real samples, including fish, shrimp, water, and soil.

Wintersweet‐Flower‐Like CoFe2O4/MWCNTs Hybrid Material for High‐Capacity Reversible Lithium Storage

CoFe(2)O(4)/multiwalled carbon nanotubes (MWCNTs) hybrid materials were synthesized by a hydrothermal method. Field emission scanning electron microscopy and transmission electron microscopy analysis confirmed the morphology of the as-prepared hybrid material resembling wintersweet flower "buds on branches", in which CoFe(2)O(4) nanoclusters, consisting of nanocrystals with a size of 5-10 nm, are anchored along carbon nanotubes. When applied as an anode material in lithium ion batteries, the CoFe(2)O(4)/MWCNTs hybrid material exhibited a high performance for reversible lithium storage. In particular, the hybrid anode material delivered reversible lithium storage capacities of 809, 765, 539, and 359 mA h g(-1) at current densities of 180, 450, 900, and 1800 mA g(-1), respectively. The superior performance of CoFe(2)O(4)/MWCNTs hybrid materials could be ascribed to the synergistic pinning effect of the wintersweet-flower-like nanoarchitecture. This strategy could also be applied to synthesize other metal oxide/CNTs hybrid materials as high-capacity anode materials for lithium ion batteries.

Ligand-modified Multi-walled Carbon Nanotubes for Potentiometric Detection of Silver

Three novel hybrid materials have been synthesized by ligands: N-(2-vinylsulfanyl-ethylidene)-benzene-1,2-dimine (SBD), N-pyridin-2-ylmethylene-benzene-1,2-dimine (NBD) and N-furan-2-ylmethylene-benzene-1,2-dimine (OBD), covalently linking to multi-walled carbon nanotubes (MWCNTs). These MWCNT hybrid materials were used both as ionophores and as ion-to-electron transducers to construct Ag(+) carbon paste electrodes. The resulting electrodes show higher selectivity to Ag(+) than other cations tested. Among the three electrodes, the electrode based on SBD-g-MWCNTs with optimum composition shows the best performance to Ag(+). It exhibits an excellent Nernstian response to Ag(+) in the concentration range from 8.8 × 10(-8) to 1.0 × 10(-1) M with a detection limit of 6.3 × 10(-8) M, and it can also be used over a wide pH range of 3.0-8.0 with a quick response time of 5 s. The response mechanism of the proposed electrode was also investigated by using AC impedance and UV-vis spectroscopy techniques.

Pseudopolyrotaxane Structure Constructed by Polycaprolactone (PCL) Grafted on Multi-Walled Carbon Nanotubes and α-Cyclodextrins

Abstract The multi-walled carbon nanotubes (MWNTs) are modified through acidification, followed by the graft of polycaprolactone. The supramolecular forces of α-cyclodextrins (α-CDs) and PCL are used to produce MWNTs hybrid materials with pseudopolyrotaxane structure. XRD, FTIR, TGA, DSC are used for the characterization of its product. The preparation of this hybrid material provides a new approach for modifying carbon nanotubes in supramolecular chemistry with the expectation of applying this hybrid materials to the field of biomedicine.