Carbon Nanotube Hybrid Materials Research Articles

Wear Behavior of Chemically Bonded Ceramic Coatings Reinforced by MWCNTs–ZnO Hybrid Material

Zinc oxide (ZnO) decorated multi-walled carbon nanotubes (MWCNTs) hybrid material was prepared to improve the tribological performance of chemically bonded ceramic coatings. TEM results reveal that ZnO has been successfully fabricated on the surface of MWCNTs. The tribological performance of the ceramic coatings with MWCNTs–ZnO hybrid material was investigated using a ball-on-disc method. The results show that the friction coefficient and wear rate of the ceramic coatings decrease with the increase of MWCNTs–ZnO hybrid material. The ceramic coatings with MWCNTs-ZnO hybrid material shows a smooth worn surface with less cracks and delamination. In addition, the worn surface of the counterpart ball shows a smaller worn area and a smooth surface. The excellent wear resistance of the ceramic coatings is attributed to the good bonding strength between MWCNTs–ZnO hybrid material and ceramic matrix.

TiO2 nanoparticle embedded nitrogen doped electrospun helical carbon nanofiber-carbon nanotube hybrid anode for lithium-ion batteries

TiO2 nanoparticles decorated nitrogen (N) doped helical carbon nanofiber (CNF)-carbon nanotube (CNT) hybrid material is prepared by low-cost electrospinning technique followed by hydrothermal method. Morphological investigations establish helical structure of CNFs with hierarchical growth of CNTs around CNFs. The hybrid material shows a high specific surface area of 295.17 m2 g−1 with nanoporous structure. X-ray photoelectron spectroscopic studies establish Ti–O–C/Ti–C bond mediated charge transfer channel between TiO2 nanoparticles and carbon structures with the success of N doping in CNFs. The electrospun hybrid material delivered high reversible charge capacities of 316 mAh g−1 (100th cycle) and 244 mAh g−1 (100th cycle) at a current density of 75 mA g−1 and 186 mA g−1 respectively. The charge capacities obtained for different applied current densities are higher than the conventional graphitic microporous microbeads anode. Results indicate that the hybrid material reported here shows high performance compare to graphite for LIBs.

Synthesis of carbon-SiO2 hybrid layer @ SiO2 @ CNT coaxial nanotube and its application in lithium storage

To alleviate the volume variation upon the silicon oxide during the lithium ion storage process and improve its cyclic stability as well as rate performance in the application of anode material in LIBs, a silicon oxide, carbon and carbon nanotube hybrid material with coaxial structure is developed here in a two-step manner. The formed Carbon-SiO2@SiO2@CNT coaxial nanotube material carries 644 mAh g−1 stable capacity under 0.1 A g−1 as the anode material in LIBs. After over 5000 operating cycles under 1 A g−1, 242 mAh g−1 reversible capacity is clearly demonstrated. The enhanced electrochemical performances can be mostly attributed to the inner carbon nanotube and outer carbon layer, both of which can relief the stress arising from the change of volume and improve the conductivity. The coaxial structure may also benefit to the lithium ions transportation.

Hybrid materials of carbon nanotubes with fluoroalkyl- and alkyl-substituted zinc phthalocyanines

In this work, hybrid materials of single-walled carbon nanotubes (SWCNT) noncovalently functionalized with fluoroalkyl- (SWCNT/ZnPc-CF) and alkyl- (SWCNT/ZnPc-CH) substituted zinc(II) phthalocyanines were prepared. The effect of fluorination of the substituents in phthalocyanine macrocycle on the functionalization degree of carbon nanotubes and sensor response to ammonia was investigated. It was shown that the type of substituents in the phthalocyanine macrocycle showed noticeable effect both on the degree of functionalization of carbon nanotubes and on the sensing performance of the investigated hybrids. The amount of phthalocyanine molecules adsorbed on SWCNT walls was shown to be 1.5 times higher in the SWCNT/ZnPc-CH hybrid. The SWCNT/ZnPc-CF layer exhibited 2 times less chemiresistive sensor response to ammonia than SWCNT/ZnPc-CH, while its sensor response was more stable at 70% relative humidity.

Mesoporous Single-Atom-Doped Graphene–Carbon Nanotube Hybrid: Synthesis and Tunable Electrocatalytic Activity for Oxygen Evolution and Reduction Reactions

Mesoporous heteroatom-doped carbon-based nanomaterials are very promising as catalysts for electrochemical energy conversion and storage. We have developed a one-step catalytic chemical vapor deposition method to grow a highly graphitized graphene nanoflake (GF)–carbon nanotube (CNT) hybrid material doped simultaneously with single atoms of N, Co, and Mo (N–Co–Mo–GF/CNT). This high-surface-area material has a mesoporous structure, which facilitates oxygen mass transfer within the catalyst film, and exhibits a high electrocatalytic activity and stability in oxygen reduction and evolution reactions (ORR and OER) in alkaline media. We have shown that in this metal (M)–N–C catalyst, M (Co, Mo)–C centers are the main sites responsible for OER, while, for ORR, both M and N–C centers synergistically serve as the active sites. We systematically investigated tuning of the ORR and OER activity of the porous catalyst depending on the choice of the underlying substrate. The ORR kinetic current and OER activity for N–Co–Mo–GF/CNT were significantly enhanced when the catalyst was deposited onto a Ni substrate, resulting in an advanced electrocatalytic performance compared to the best bifunctional ORR/OER catalysts reported so far. Using a developed scanning electrochemical microscopy analysis method, we demonstrated that the higher OER reactivity on Ni was attributable to the formation of underlying catalyst/Ni interfacial sites, which are accessible due to the porous, electrolyte-permeable structure of the catalyst.

Electrochemical investigation on high-rate properties of graphene nanoplatelet-carbon nanotube hybrids for Li-ion capacitors

Li-ion capacitors (LICs) are considered a bridging electrochemical energy device between Li-ion batteries and supercapacitors. Graphene nanoplatelet (GNP)‑carbon nanotube (CNT) hybrid materials can be a good candidate for negative electrode materials used in LICs. The rate performance of LIC negative electrodes plays a key role in increasing the power density of LICs. In this study, the Li storage kinetics of a GNP-CNT hybrid electrode was investigated. CNTs were directly grown on the GNP surfaces through chemical vapor deposition via transition metal oxide seeding. Natural graphite, GNP, and mixture (GNP and CNT) electrodes were used as the control electrodes. The kinetics was evaluated using electrochemical analysis tools such as galvanostatic charge-discharge cycling at various current densities, cyclic voltammetry, galvanostatic intermittent titration technique, and electrochemical impedance spectroscopy. The results revealed that the direct growth of CNTs on the GNP surfaces led to strong contact between these materials. This contact could play a pivotal role in the improvement of reversible Li storage kinetics characterizing negative electrodes for high-power LICs.

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.

Ultra-Small Fe2N/N-CNTs as Efficient Bifunctional Catalysts for Rechargeable Zn-Air Batteries

Zinc-air batteries (ZABs) have been considered as promising next-generation batteries due to their natural abundance, flat discharge voltage and high theoretical specific energy density. However, the wide application of these ZABs is seriously hindered by the high cost and poor electrochemical stability of noble electrocatalysts. In this paper, we develop a facile method to prepare ultra-small iron-based nitride and nitrogen doped carbon nanotubes (Fe2N/N-CNTs) hybrid materials as bifunctional electrocatalysts for ZABs. In the presence of CNTs with large surface areas, ultra-small Fe2N nanoparticles with the diameter of around 5 nm are successfully prepared. The oxygen reduction reaction (ORR) activity of Fe2N/N-CNTs is comparable to the Pt/C, while the oxygen evolution reaction (OER) activity is much better than the Pt/C. At last, the home-made ZABs with Fe2N/N-CNTs have significant rechargeable activities and cyclic stability.

Hexagonal boron nitride-carbon nanotube hybrid network structure for enhanced thermal, mechanical and electrical properties of polyimide nanocomposites

This study suggests the simple and effective synthesis method of chemically interconnected hexagonal boron nitride (h-BN)–carbon nanotubes (CNTs) hybrid materials (BN–Fe-CNT) with aminosilane functionalized iron oxide nanoparticles (NH2–Fe) via amide bond formations. Synthesized BN-Fe-CNT was acting as an effective filler that enhanced the mechanical, thermal, and electrical properties of polyimide (PI) nanocomposites and accelerated polycondensation reaction of poly(amic acid) (PAA) due to its high thermal conductivity and heat diffusivity. At a 2 wt% filler reinforcement, the in-plane thermal conductivity of the BN-Fe-CNT/PI reached 15 W m−1 K−1 at 200 °C, which represents an enhancement of approximately 11430% compared to that of pure PI. Moreover, thermal stability was enhanced from 400 °C to 570 °C. Furthermore, the connected CNTs between the individual h-BN produced electron pathways through the PI matrix, with the BN-Fe-CNT/PI exhibiting 106 times higher electrical conductivity than that of pure PI. The results in this study clearly suggested that the BN-Fe-CNT could be applicable as an effective multi-functional reinforcement in the fabrication of lightweight polymer nanocomposites with superior mechanical properties, high thermal properties, and high electrical conductivities.

Polypyrrole-multi walled carbon nanotube hybrid materialsupported Pt NPs for hydrogen evolution from the hydrolysis of MeAB at mildconditions

Herein, we report a facile method for the preparation ofpolypyrrole-multi walled carbon nanotube hybrid material including Pt nanoparticles(Pt@PPy-MWCNT NPs) and the use in methylamine borane (MeAB) for hydrolysis reactionat mild conditions. The prepared catalyst of Pt@PPy-MWCNT NPs was characterized bysome advanced analytical methods. The catalytic experiments showed the Pt@PPy-MWCNTNPs can catalyze MeAB in aquatic solution with high catalytical performance at mildconditions. The reaction rate of catalytic hydrolysis with Pt@PPy-MWCNT NPs wasfound to be-d[CH3NH2BH3]/dt = + d[H2]/3dt = kobs[Pt@PPy-MWCNT]1.19[MeAB]0.88. The TOF value for the hydrolysis of MeABcatalyzed with Pt@PPy-MWCNT NPs was detected to be 10234.2 1/h (170.57 1/min) whichis very high compared with TOF values found for other catalysts. Enthalpy, entropyand activation energy for the hydrolysis of MeAB were calculated to be31.57 kJ mol−1,−119.97 J mol−1 K and34.27 kJ mol−1, respectively.

A composite with botryoidal texture prepared from nitrogen-doped carbon spheres and carbon nanotubes for voltammetric sensing of copper(II)

Mercury-based electrodes have been employed for the electrochemical determination trace level of heavy metals. However, due to the toxicity of mercury, mercury-free materials are encouraged to develop for on-site monitoring of heavy metals. In this work, N-doped carbon spheres/multi-walled carbon nanotubes (N-CSs/MWCNTs) hybrid materials were successfully fabricated with a low-cost convenient method. The synthesized N-CSs/MWCNTs composites were used to fabricate chemically modified electrode for selective and sensitive determination Cu(II) by differential pulse anodic stripping voltammetry (DPASV). Under the optimized experimental conditions, the proposed electrode displayed a good linear dynamic range of 0.5–200 μg L−1 with a correlation coefficient of 0.99. Its limit of detection (LOD) was estimated to be 0.092 μgL−1. Moreover, the repeatability, reproducibility, and stability of the modified electrode were also explored. Finally, the proposed electrode can be applied to quantify Cu(II) content in lake water and human saliva samples.

New electromagnetic shielding materials based on viscose‐carbon nanotubes composites

A convenient approach for the preparation of cellulose ‐ carbon nanotubes (CNT) hybrid materials owning electromagnetic shielding properties, based on viscose (V) and TEMPO‐oxidized viscose fibers (VO) is proposed. Viscose ‐ carbon nanotubes (V‐CNT) and TEMPO‐oxidized viscose ‐ carbon nanotubes (VO‐CNT) composites were prepared by embedding carbon nanotubes on the surface of two types of cellulose fibers, that is, viscose and its C6‐oxidized derivative. The chemical composition, morphology, and thermal stability of the prepared hybrid materials were thoroughly investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analyses. Moreover, electrical properties of the original and composite fibers were assessed. POLYM. ENG. SCI., 59:1499–1506 2019. © 2019 Society of Plastics Engineers

Fe3O4 Nanoparticles Supported on Arc‐synthesized Carbon Nanotubes as Advanced Electrocatalyst for Oxygen Reduction Reaction

AbstractOxygen reduction reaction (ORR) is an important half reaction in many renewable energy conversion and storage sources. The development of efficient, cost‐effective and durable non‐precious ORR catalysts with their catalytic efficiencies close to expensive Pt‐based catalysts is promising towards large‐scale practical applications of fuel cells and metal‐air batteries. Herein, we report a facile and scalable in‐situ synthesis of Fe3O4 nanoparticles supported on carbon nanotubes hybrid material using arc‐discharge method in low‐pressure air and use Fe3O4/CNTs hybrid as a highly efficient ORR electrocatalyst. The as‐synthesized Fe3O4/CNTs catalyst shows excellent ORR catalytic activity with its performance close to or even better than the commercial 20wt% Pt/C in alkaline media due to the synergistic effect between Fe3O4 and CNTs. This study provides a new insight into non‐precious metal ORR catalysts that are feasible in alkaline membrane fuel cells and metal‐air batteries.

Facile fabrication of WO3/MWCNT hybrid materials for gas sensing application

Hybrid materials of tungsten oxide (WO3) and multi-walled carbon nanotubes (MWCNTs) were fabricated by a facile method using acid precipitation route. Ammonium tungstate para-pentahydrate was supplied to a designated amount of MWCNTs to prepare a precipitate of tungsten compound hybridizing with MWCNT surface in prior to calcination with air in a temperature range of 300–600 °C. Morphology, crystalline, functional groups on surface, porosity and thermal stability of synthesized hybrid material were characterized by SEM, XRD, Fourier transform Raman spectroscopy, TGA and BET analyses. It could be confirmed that the prepared WO3/MWCNT hybrid materials possessed very high BET surface area and mesoporous characteristics with good thermal stability which would be beneficial to their application as thick-film sensors.

Dense monolithic MOF and carbon nanotube hybrid with enhanced volumetric and areal capacities for lithium–sulfur battery

Densely packed metal–organic framework (MOF) and carbon nanotube (CNT) hybrid materials with tailored hierarchical porous structures are prepared by in situ growth and room temperature drying/shrinking for high-performance compact energy storage systems.

Catalytic and Photocatalytic Nitrate Reduction Over Pd-Cu Loaded Over Hybrid Materials of Multi-Walled Carbon Nanotubes and TiO2.

TiO2 and carbon nanotube-TiO2 hybrid materials synthesized by sol-gel and loaded with 1%Pd−1%Cu (%wt.) were tested in the catalytic and photocatalytic reduction of nitrate in water in the presence of CO2 (buffer) and H2 (reducing agent). Characterization of the catalysts was performed by UV-Vis and fluorescence spectroscopy, X-ray diffraction, temperature programed reduction, N2 adsorption, and electron microscopy. The presence of light produced a positive effect in the kinetics of nitrate removal. Higher selectivity toward nitrogen formation was observed under dark condition, while the photo-activated reactions showed higher selectivity for the production of ammonium. The hybrid catalyst containing 20 %wt. of carbon nanotubes shows the best compromise between activity and selectivity. A mechanism for the photocatalytic abatement of nitrate in water in the presence of the hybrid materials was proposed, based in the action of carbon nanotubes as light harvesters, dispersing media for TiO2 particles and as charge carrier facilitators.

Compact and low loss electrochemical capacitors using a graphite / carbon nanotube hybrid material for miniaturized systems

With the establishment of the internet of things (IoT) and the rapid development of advanced microsystems, there is a growing demand to develop electrochemical capacitors (ECs) to replace bulky electrolytic capacitors on circuit boards for AC line filtering, and as a storage unit in energy autonomous systems. For this purpose, ECs must be capable of handling sufficiently high signal frequencies, display minimum energy loss through self-discharge and leakage current as well as maintaining an adequate capacitance. Here, we demonstrate ECs based on mechanically flexible, covalently bonded graphite/vertically aligned carbon nanotubes (graphite/VACNTs) hybrid materials. The ECs employing a KOH electrolyte exhibit a phase angle of −84.8°, an areal capacitance of 1.38 mF cm−2 and a volumetric capacitance (device level) of 345 mF cm−3 at 120 Hz, which is among the highest values for carbon based high frequency ECs. Additionally, the performance as a storage EC for miniaturized systems is evaluated. We demonstrate capacitive charging/discharging at μA current with a gel electrolyte, and sub-μA leakage current reached within 50 s, and 100 nA level equilibrium leakage within 100 s at 2.0 V floating with an ionic liquid electrolyte.

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.

Preparation of Multiwall Carbon Nanotubes with Zinc Phthalocyanine Hybrid Materials and Their Nonlinear Optical (NLO) Properties.

Hybrid material of multi walled carbon nanotubes (MWCNT)-zinc phthalocyanine (ZnPcs) (MWCNT-ZnPc) composites were synthesized and compared with ZnPc. Nonlinear optical properties of MWCNT-ZnPc and ZnPc were studied. The synthesized MWCNT-ZnPc characterized by UV-visible absorption spectroscopy, photoluminescence and TEM. Their nonlinear optical properties were measured through Z-scan technique with 800 nm, 110 fs, 1 kHz Ti:Sapphire laser and 532 nm, 30 ps and 10 Hz Nd:YAG laser. The results showed that phthalocyanines were anchored onto the surface of the multi walled carbon nanotubes by using TEM. Photoluminescence spectra had shown quenching in emission of MWCNT-ZnPcs hybrid material due to the energy transfer. Reverse saturable absorption in MWCNT-ZnPcs hybrid material was compared with pure phthalocyanine, which had shown an increase in nonlinear absorption coefficient with 532 nm and reduction with 800 nm. The results concluded that MWCNT and MWCNT-ZnPc can be used as effective optical limiters.