Synthesis Of Multi-walled Carbon Nanotubes Research Articles

The effect of TiO2 doped multi-walled carbon nanotubes synthesis on the thermophysical and heat transfer properties of transformer oil: A comprehensive experimental study

The study was performed on the impact of adding hydrophobic TiO2 doped on multi-walled carbon nanotubes (MWCNTs) on the heat transfer performance, breakdown voltage (BDV), and thermophysical properties (thermal conductivity coefficient, volumetric specific heat, resistivity, diffusivity, viscosity, and viscosity index (VI)) of transformer oil (TO). The novelty of this study is the use of TiO2 doped MWCNTs nanoparticles synthesized in TO and a comprehensive experimental investigation of the properties of nanofluids. Experiments were conducted in heat transfer systems with four nanofluids, comprising TiO2 doped MWCNTs/TO at concentrations of 0.05, 0.1, 0.15, and 0.2 wt % in four input powers of 50.5, 75.6, 100, and 124 (W) in two current regimes, free air flow and forced air flow (using two blowers). For these purposes, hybrid nanoparticles were synthesized and the nanoparticles were confirmed using analyses including FTIR, XRD, SEM, and EDX. The maximum enhancement in the VI of nanofluids at 0.2 wt% of hybrid nanoparticles was equal to 34.86%. The maximum improvement in natural and forced heat transfer coefficient of nanofluids (NCHT and FCHT), which increased by 23.08% and 24.68%, respectively. According to the results, nanofluid with 0.1 wt% had good performance compared to other concentrations of nanofluids.

Effect of Modifying Carbon Materials with Metal Phthalocynines and Palladium on Their Catalytic Activity in ORR

Bimetallic catalysts based on multi-walled carbon nanotubes (MWCNT), graphene oxide (GO) and ultradispersed diamonds (UDD) supports for the process of electroreduction of oxygen from alkaline electrolyte were obtained using high-temperature synthesis. The materials were characterized by low-temperature nitrogen adsorption, Raman spectroscopy, scanning electron microscopy and X-ray structure analysis. The synthesized bimetallic catalysts contain meso- and micropores. Based on the study by Raman spectroscopy, it is shown that high-temperature synthesis of MWCNT with metal phthalocyanines leads to doping of this material with nitrogen and the appearance of significant defects in the structure. Carbon nanotube-based catalysts showed enhanced activity compared to other carbon materials. Moreover, bimetallic catalysts based on cobalt phthalocyanine and palladium (MWCNT_CoPc_Pd) are characterized by higher activity on all carbon supports compared to materials contain on copper and palladium. The specific current density in the diffusion region of the MWCNT_CoPc_Pd catalyst is comparable to a commercial platinum electrode (Pt(20%)/C) and equals to 2.65 mA/cm2. The area of the electrochemically active surface of all the obtained catalysts was calculated from the CV data in a nitrogen atmosphere. The MWCNT_CoPc_Pd catalyst is characterized by high corrosivity: after 2500 revolutions, the current density in the diffusion region decreases by 7%, and, also, an increase in the values of E1/2 and Eonset is observed.

Examination of the Effect of RF Field on Fe-MWCNTs and Their Application in Medicine

Carbon nanotubes are a material with excellent properties, which result in a wide range of possible applications, from electronics to medicine. This paper presents the investigation of the possibility of Fe-MWCNTs’ application as heating agents for targeted thermal ablation of cancer cells, which could lead to the development of an innovative cancer treatment method. The article describes the process of synthesis of multi-walled carbon nanotubes filled with iron (Fe-MWCNTs) and provides an examination of their magnetic properties. Fe-MWCNTs were synthesized by catalytic chemical vapor deposition (CCVD). Relevant properties of the nanoparticles in terms of functionalization for biomedical applications were exploited and their magnetic properties were investigated to determine the heat generation efficiency induced by exposure of the particles to an external electromagnetic field. The reaction of the samples was measured for 40 min of exposure. The results showed an increase in sample temperature that was proportional to the concentration.

Synthesis of MWCNTs from xylenes for fabrication of highly electrically conductive and gas-sensitive polymer composites

For Multi-Walled Carbon Nanotubes (MWCNTs), high quality, purity, and low cost are very desirable. Therefore, in this reported research work, qualitative and pure MWCNTs were synthesized using a cheap and affordable carbon source-xylenes (a mixture of isomers) by the Aerosol Chemical Vapor Deposition Method (A-CVD). The high quality, purity, and homogeneity of the synthesized material have been verified by Raman spectroscopy, EDX, XRD, and SEM results. In the present study, Polystyrene/xMWCNT, Polyvinyl acetate/xMWCNT, and Polyvinyl alcohol/xMWCNT composites with different MWCNT contents of (x = 1, 2, 4, 8, and 16) wt% were prepared by an optimized technique for irreversible dispersion of MWCNTs inside polymers, which was developed by our research group. SEM analysis results revealed that the MWCNTs are well incorporated inside all three polymer matrices, and a highly dispersed distribution of MWCNTs has been obtained inside all three matrices due to this technique. Also, the electrical conductivity of the prepared composites was measured, and the prepared nanocomposites show high electrical conductivity for all concentrations of MWCNTs. Based on the maximum dispersion of MWCNTs inside the PS polymer matrix, the highest electrical conductivity is observed for this composite, which once more proves that the dispersion technique as well as the nature of the polymer play an important role in the preparation of highly electroconductive nanocomposites (1%-0.136 S/m; 2%-1.053 S/m; 4%-5.376 S/m; 8%-71.48 S/m; 16%-933.71 S/m). Comparison of electrical conductivity results of these composites with literature results demonstrates the advantages of this technique in substitution of the another dispersion methods. The nanocomposites prepared by our research group also show a sensor effect (change of resistivity) under different gases (methane, propane, carbon monoxide). It is interesting that, for analyzed gases, the resistivity of some nanocomposites increased, whereas for others it decreased. This effect can be explained by the different nature of the adsorption interaction between the analyzed gas and the polymer composite, and this depends on the chemical composition and properties of both gases and polymer matrices.

Directly Using Red Sandstone as a Catalyst to Synthesize Multi-Walled Carbon Nanotubes

Natural catalysts used in the synthesis of carbon nanotubes have significant cost advantages due to their huge reserves, but natural minerals often require complicated pretreatments to obtain satisfactory products. In this study, red sandstone was directly used as a catalyst for the synthesis of multi-carbon nanotubes by chemical vapor deposition without complicated pretreatment. The SEM, TEM, Raman and TG characterization of the products at different growth temperatures ([Formula: see text]C, [Formula: see text]C and [Formula: see text]C) showed that [Formula: see text]C is the optimal condition for the growth of multi-walled carbon nanotubes (MWCNTs) by red sandstone. High-quality multi-wall carbon nanotubes can be obtained with a relatively high yield, and the [Formula: see text] of the product reaches 1.78, which exceeds that of many commercial multi-wall carbon nanotubes. Compared with other natural materials as catalysts for the synthesis of MWCNTs, red sandstone has a huge cost advantage because it can catalyze the synthesis of high-quality MWCNTs at [Formula: see text]C without complicated pretreatment.

Multi-walled Carbon Nanotubes Synthesis from Ethanol and 2-Propanol by Chemical Vapor Deposition

Multi-walled Carbon Nanotubes Synthesis from Ethanol and 2-Propanol by Chemical Vapor Deposition

Biocompatible and Antimicrobial Cellulose Acetate-Collagen Films Containing MWCNTs Decorated with TiO2 Nanoparticles for Potential Biomedical Applications.

This research focuses on the synthesis of multi-walled carbon nanotubes (MWCNTs) decorated with TiO2 nanoparticles (NPs) and incorporated in cellulose acetate-collagen film in order to obtain a new biomaterial with potential biomedical applications and improved antimicrobial activity. The successful decoration of the MWCNTs with TiO2 NPs was confirmed by several structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction and transmission electron microscopy. The obtained nanocomposites were further incorporated into cellulose acetate-collagen films, at different concentrations and absorption kinetics, antimicrobial activity and in vitro biocompatibility of the obtained films was investigated. The antimicrobial tests sustained that the presence of the nanocomposites into the polymeric matrix is an important aspect in increasing and maintaining the antimicrobial activity of the polymeric wound dressings over time. The biocompatibility and cytotoxicity of the obtained films was evaluated using cellular viability/proliferation assay and fluorescent microscopy which revealed the ability of the obtained materials as potential wound dressing biomaterial.

Carbon Nanotubes: Synthesis via Flame Fragment Deposition (FFD) Method from Liquefied Petroleum Gas

The current study uses the flame fragment deposition (FFD) method to synthesize carbon nanotubes (CNTs) from Iraqi liquefied petroleum gas (LPG), which is used as a carbon source. To carry out the synthesis steps, a homemade reactor was used. To eliminate amorphous impurities, the CNTs were sonicated in a 30 percent hydrogen peroxide (H2O2) solution at ambient temperature. To remove the polycyclic aromatic hydrocarbons (PAHs) generated during LPG combustion, sonication in an acetone bath is used. The produced products were investigated and compared with standard Multi-walled carbon nanotube MWCNTs (95%), Sigma, Aldrich, using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), Raman spectroscopy, scanning electron spectroscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Transmission Electron Microscopy (TEM). Under the applied experimental circumstances, the obtained characterization data confirm the synthesis of multi-wall carbon nanotubes (MWCNTs) with portion from few wall carbon nanotubes (FWCNTs). The average diameter of synthesized Carbon nanotubes ranged from 31.26 to 78.00 nm, with a purity of more than 65 percent.

Multiwalled Carbon Nanotube Based Solid- Phase Extraction Cartridges and its Application in Waste Water Analysis

Isolation of different organic impurity from industrial waste water was carried out using solid phase extraction (SPE) cartridges and analyzed by reverse phase high performance liquid chromatography. Kalonji oil-a rich source of carbon, easily available in nature and cheap is used as a naturally occurring precursor for the synthesis of Multiwalled Carbon Nanotubes (MWCNTs) in laboratory by chemical oil vapor deposition technique (COVD) by direct pyrolysis at 800°C in an inert gas (Hydrogen) atmosphere. The obtained MWCNTs were purified by acid treatment and characterized by different analytical tools such as XRD (X-ray diffraction), SEM (Scanning Electron Microscope) and FTIR (Fourier Transform Infra-Red Spectroscopy), BET surface area analyser.These MWCNTs used directly to prepare solid phase extraction cartridges in laboratory and studied its application in isolation of organic impurities (Aniline and Phenol) from industrial waste water followed its identification by RP - HPLC (Reverse phase High performance liquid chromatography analysis).

Temperature-dependent synthesis of multi-walled carbon nanotubes and hydrogen from plastic waste over A-site-deficient perovskite La0.8Ni1-xCoxO3-δ

Thermochemical conversion of plastic wastes into carbon nanotubes (CNTs) and hydrogen is a promising management option to eliminate their hazardous effect. The yields and morphologies of CNTs strongly depend on the catalyst design and reaction conditions. To boost the efficiency, tuning of bimetallic nanoparticles as catalyst is an effective approach. For that reason, A-site-deficient perovskite La0·8Ni1-xCoxO3-δ (LN1-xCx, x = 0.15, 0.5, 0.85) was developed and used as a catalyst precursor to achieve in situ formation of bimetallic Ni–Co nanoparticles. At an optimized Ni-to-Co ratio, the LN0.5C0.5 exhibited the highest yields of multi-walled CNTs, namely 840 and 853 mg/gcatalyst from high density polyethylene and polypropylene, respectively. This could be attributed to the higher catalytic capability of LN0.5C0.5 catalyst for the decomposition of hydrocarbons into hydrogen and carbon. In both cases, multi-walled CNTs had regular shapes when the reaction temperature was 700 °C. At higher reaction temperatures, the morphological changes of carbon products were observed from multi-walled CNTs to carbon nano-onions. The Raman spectra showed that compared with the commercial multi-walled CNTs, the as-prepared multi-walled CNTs had a lower degree of defects.

Synthesis of multi-walled carbon nanotubes decorated with silver metallic nanoparticles as a catalytic degradable material via pulsed laser ablation in liquid media

Multi-walled carbon nanotube decorated with silver nanoparticles (MWCNTs/Ag nanocomposite) was prepared with clean, simple, and one-pot method as catalytic degradable material for nitro compounds and dyes. This method based on using Nd:YAG (1064 nm, 10 Hz, and 7 ns) for the ablation of silver plate immersed in functionalized MWCNTs solution. The prepared nanocomposite material was investigated by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and the thermal gravimetric analysis (TGA). The prepared sample was studied as a catalyst for the reduction of hazardous 4-nitrophenol, methyl orange, and methylene blue. This study represents that Ag-MWCNTs nanocomposite has a promising catalytic rate constant for the reduction of 4-NP, MO, and MB with values 0.0055 s −1 , 0.017 s −1 , and 0.0098 s −1 , respectively. This research is considered as a powerful, feasible, environmentally safe, and cost-effective route for the production of a powerful catalyst for the degradation of hazardous materials and dyes. • Ag-MWCNTs nanocomposite was synthesized by ablation of Ag plate in f -MWCNTs. • The as-prepared nanocomposite has a good catalytic activity. • The produced nanocomposite has high distribution without using any surfactant. • The nanocomposites were synthesized via simple one-pot green method. • The resulted nanocomposites were characterized by XRD, Raman, XPS, TEM, and TGA.

Multi-walled Carbon Nanotubes Synthesis by Arc Discharge Method in a Glass Chamber

Abstract. In the present paper, carbon nanotubes (CNTs) were synthesized by arc discharge method by vaporizing graphite rods in the presence of Ni and a Ni/Y mixture as catalysts for subsequent use in electrical energy storage and conversion devices. CNTs synthesis was carried out in a cylindrical glass reactor applying a controlled Argon flow of 1.43 cm3/min and a chamber pressure of 39 kPa. Carbon powder was collected from the reactor following chemical treatment with HCl solution at 1 M to remove the metallic impurities. Morphology obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed multi-walled nanotubes (MWCNTs) with amorphous carbon particles attached to their surface. Fourier transform infrared (FT-IR) spectra presented bands at 1550 and 1200 cm–1 corresponding to the C=C bond characteristic to the CNTs skeleton; these bands were not present in pristine graphite. Electromagnetic absorbance was observed using ultraviolet-visible spectroscopy (UV-Vis) showing peaks at 204 and 256 nm related to sp2 hybridization characteristic for MWCNTs.
 
 Resumen. En el presente trabajo se sintetizaron nanotubos de carbono (NTCs) por el método de descarga de arco mediante la vaporización de barras de grafito en presencia de Ni y una mezcla de Ni/Y como catalizadores para su posterior uso en dispositivos de almacenamiento y conversión de energía eléctrica. La síntesis de NTCs se realizó en un reactor cilíndrico de vidrio aplicando un flujo controlado de Argón de 1.43 cm3/min y una presión de cámara de 39 kPa. El polvo de carbón se recolectó del reactor y se trató químicamente con una solución de HCl a 1 M para eliminar las impurezas metálicas. La morfología obtenida por microscopía electrónica de barrido (MEB) y microscopía electrónica de transmisión (MET) mostró nanotubos de paredes múltiples (NTCPMs) con partículas de carbón amorfo adheridas a su superficie. Los espectros de infrarrojo transformada de Fourier (FT-IR) mostraron bandas en 1550 y 1200 cm–1 que corresponden al enlace C=C característico de los NTCs; estas bandas no estuvieron presentes en el grafito prístino. La absorbancia electromagnética se observó mediante espectroscopia ultravioleta-visible (UV-Vis) mostrando picos a 204 y 256 nm relacionadas con la hibridación sp2 característica de los NTCPMs.

Synthesis of Carbon Nanotubes (CNTs) from Poultry Litter for Removal of Chromium (Cr (VI)) from Wastewater.

Pakistan, an agricultural country, raises 146.5 million commercial and domestic poultry birds, which generate around 544,831 tons of waste per year. This waste finds its final disposal in agricultural land as soil fertilizer or disposal site amendment. The usage of poultry litter for this purpose is uncontrolled, which results in environmental degradation such as emission of greenhouse gases, e.g., methane. However, alternative options such as thermochemical conversion of poultry litter can offer better solutions where this waste can be used as a low-cost carbon source for the synthesis of Multiwalled Carbon Nanotubes (MWCNTs). In this study, efforts were made to utilize this cheap and plentiful carbon source for the synthesis of CNTs in the presence of Ni/Mo/MgO as a catalyst, through pyrolysis. For a better yield of carbon product, the optimum ratio for the catalysts (Ni/Mo/MgO) was found to be 4:0.2:1. Furthermore, the process parameters were also optimized for better carbon yield. A good yield of CNTs resulted from a pyrolysis time of 12 min, a temperature of 825 °C, and a catalyst weight of 100 mg. The structure and morphology of the produced nanotubes were confirmed through X-ray Diffractometer (X-RD) and Scanning Electron Microscopy (SEM). The environmental application of the nanotubes was tested in a synthetic chromium solution in the lab using a batch experiment. Different experimental conditions (pH, adsorbent dosage, and contact time) were optimized to improve the adsorption of Cr (VI) by carbon nanotubes and a UV-Visible spectrophotometer was used at 540 nm to measure the absorbance of Cr (VI). The results showed that up to 81.83% of Cr (VI) removal was achieved by using 8 mg of CNTs at pH 3 with 400 rpm at 180 min of contact time. Thus, it was concluded that poultry litter can be a useful source for the synthesis of MWCNTs and thereby removal of Cr (VI) from industrial tanneries’ wastewater.

Multiwalled carbon nanotubes synthesis from methane using a stainless steel foils as a catalyst

In this study, a thin stainless-steel foil was used as a catalyst for carbon nanotubes (CNTs) using methane as a carbon source via the chemical vapor deposition (CVD) method. Our results revealed that pre-treatment step of the catalyst plays an important role in CNT formation. In our experiments, a catalyst pre-treatment temperature of 850 oC have been found to facilitate the surface roughness and provide more active nucleation sites for CNTs formation. Multiwalled CNTs with 6 layers, their diameters of 10 – 20 nm and their length of app. 300 nm were grown. This finding might lead to a process for improving the quality of MWCNTs grown on steel foil as catalyst.

Global scale life cycle environmental impacts of single- and multi-walled carbon nanotube synthesis processes

Carbon nanotubes (CNTs) are well known for their mechanical resistance, durability and flexibility, which make them preferable for a wide variety of applications. The global production volume of CNTs is expected to reach 7,000 tons by 2025. This work performs cradle-to-gate life cycle assessments (LCAs) of industrially preferred single- and multi-walled CNTs synthesis processes. The aim is to evaluate global environmental impacts associated with raw materials acquisition and manufacturing and identify hotspots in CNTs production. Eight single-walled and seven multi-walled CNTs synthesis processes are evaluated using LCA. A mass based functional unit is selected as 1 kilogram of CNTs produced, and LCAs are conducted using SimaPro 8.5.2 Software with Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI 2.1) and Cumulative Energy Demand (CED) impact categories. It is expected that industrial scale production provides significant material and energy savings as well as reduces environmental impacts per unit mass of the product, due to the use of efficient equipment and recycling of reagents. Therefore, hypothetical scaling up scenarios are applied in order to estimate associated impacts. Lastly, industry-based impact projections are developed for industries where the majority of CNTs are used using the Laplace criterion. The results showed that chemical vapor deposition is the most impactful route for manufacturing single- and multi-walled CNTs. Whereas, high pressure carbon monoxide route for producing single-walled CNTs, and arc discharge route for manufacturing multi-walled CNTs are found to be the least environmentally impactful techniques among different processes considered. Results indicate that the preference of synthesis process dominates the overall environmental cost of the CNTs as well as CNTs-enabled products. Additionally, using different scaling up scenarios, it is projected that the environmental emissions associated with producing CNTs may be reduced up to 88% globally. As industries use particular routes to synthesize the CNTs to be embedded in their products, it is found that the sectoral environmental impacts are not proportional with the industrial shares. CNTs offer technological advances to conventional products (e.g. heated jacket). However, thinking from a global scale, manufacturing CNTs has significant environmental impacts. This study provides segmented impact projections for industries, which then may be used to inform sectoral cradle-to-grave environmental impacts as a function of manufacturing processes. Based on the desired characteristics of produced CNTs (e.g. diameter, surface area), manufacturing CNTs with environmentally responsible production routes may help decreasing global environmental impacts significantly.

Thermophysical properties of nanofluids MWCNT (multi-walled carbon nanotubes) in water for emergency coolant from nuclear reactors

To evaluate the synthesis and characterization of MWCNT (Multi-walled Carbon Nanotubes) with different degrees of functionalization in distilled water. The thermophysical properties (thermal conductivity and viscosity) of these nanofluids were measured at a temperature range (20-60°C) and concentrations (0.005-0.05%) by volume. Increases in thermal conductivity and viscosity were found 9.3% and 4.7%, respectively, at a volumetric concentration of 0.01% at a temperature of 30°C. The study of new fluids that improve the rate of removal of heat is fundamental to obtain greater efficiency of energy systems. Among the several factors that compromise the efficiency of the energy systems, we can highlight the thermophysical limitations of the conventional fluids, inhibiting in a very significant way some industrial applications. In this work we intend to improve the heat transfer characteristics of fluids commonly used by the addition of nanoparticles, made up of carbon nanotubes, in water which is the most used fluid for the cooling of nuclear reactors in operation today. It is intended to improve the heat transfer characteristics of fluids commonly used by the addition of nanoparticles, made of carbon nanotubes, through the addition of nanoparticles, made up of carbon nanotubes, in water which is the most used fluid for refrigeration of nuclear reactors currently in operation. In order to assess its benefits for the applicability and nuclear systems, ie primary coolant, safety systems, major accident mitigation strategies.

Low-cost synthesis of multi-walled carbon nanotubes using red soil as catalyst

Low-cost catalysts are of great significance for the batch synthesis of carbon nanotubes. In this study, the low-cost red soil was directly used as a natural catalyst to catalyze the growth of multi-walled carbon nanotubes (MWCNTs). The results of SEM, TEM, Raman, TG and carbon yields of the products consistently showed that 400 °C calcined red soil lead to high quality MWCNTs growth, the Raman IG/ID of the product is 1.66, which indicates that the product has exceeded the graphitization of many industrially synthesized MWCNTs. The high catalyzation efficiency may be attributed to the fact of composition characteristics that red soil lacks alkali metals and alkaline earth metals but is rich in iron and aluminum oxide, making the composition of red soil similar to the catalyst composition used in the synthesis of carbon nanotubes by common chemical vapor deposition method. Meanwhile the impurity content is less than other natural catalytic materials. The porous structure formed after proper calcination has also played a positive role to the catalytic growth of MWCNTs, which improved catalyst utilization by facilitating the gas phase diffusion. We explored a technique for synthesis of high-quality MWCNTs at low cost using soil as a catalyst.

A new approach to the economic synthesis of multi-walled carbon nanotubes using a Ni/MgO catalyst

The present paper describes the efficiency of the synthesis of multi-walled carbon nanotubes (MWCNTs), which is achieved through the implementation of a non-standard approach to the preparation of a Ni/MgO catalyst. The catalyst required for MWCNTs synthesis was obtained through chemical vapor deposition method. At the same time, the pre-catalyst was treated by electromagnetic field, ultrasound and microwave waves methods. It was proved that the treatment of the catalyst initial components solution with the electromagnetic field, ultrasound and microwaves contributes to an increase in the yield of the synthesized MWCNTs by 50, 30 and 70%. Besides, ultrasonic treatment may be used if MWCNTs of relatively low degree of a defect are required. The proposed approach is economically feasible since small additional energy costs lead to a more complete conversion of carbon-containing raw materials into the target product at the activation stage. The reported method may be used to prepare MWCNTs of different types economically; leading to its industrial application to produce different types of MWCNTs.

Preparation of diameter-controlled free-standing MWCNT membranes and their application for dye adsorption.

The synthesis of multi-walled carbon nanotubes (MWCNTs) was carried out over different Ni-loaded metallic oxide catalyst nanoparticles and under different reduction times to control the outside diameter of the nanotubes. Moreover, high-purity, free-standing membranes were fabricated by a simple filtration of the as-grown MWCNTs. Furthermore, the dye-adsorption properties of the nanotubes depended on the diameter of the carbon nanotubes (CNTs). The adsorption isotherms and kinetics of anionic dyes could be described by Freundlich and pseudo-second-order models, respectively. Thermodynamic studies suggested that the adsorption processes were spontaneous and exothermic. This work provides new insights into the synthesis and application of MWCNTs with the selective adsorption properties of carbon-based materials for the removal of organic dyes.

Effect of pyrolysis temperature on the synthesis of high-quality MWCNTs by CVD method

Production of high-quality Multi-Walled Carbon Nano-Tubes (MWCNTs) is essential in some field, especially in medical and mechanical applications. This work illustrates the synthesis of high-quality (MWCNTs) by Injection Chemical Vapor Deposition (Inj-CVD) method using Ferrocene / Toluene solution as a carbon precursor and a catalyst. The effect of synthesis pyrolysis temperature, which has a pivot impact on the synthesis process, was investigated. The structure defects, impurities, thermal stability and sample morphology, as well as the mean diameters of the MWCNTs, were analyzed using Raman spectroscopy, thermal gravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. The results revealed that a change in quality, mean diameter and purity were observed when the pyrolysis temperature varied between 700°C to 850°C. High-quality MWCNTs were observed by Raman spectroscopy at a pyrolysis temperature of 700°C with ID/IG = 0.2. While the outer and inner diameters were 25±6 nm and 7.8±1.5nm respectively, measured by Transmission Electron Microscope (TEM). The Inj-CVD shows an excellent control of the quality of the prepared MWCNTs by optimizing the synthesis temperature.