Mass Production Of Carbon Nanotubes Research Articles

The NH4Cl/Rice Husk Carbon as Promoters and Assisted Carbon Sources in Catalyzing Polypropylene into Carbon Nanotubes

AbstractContinuously increasing practical relevance required the mass production of carbon nanotubes (CNTs) through environmentally benign and sustainable routes. In the work, it is found that loading trace amounts of NH4Cl on rice husk carbon can effectively act as promoters and assisted carbon source inthe catalytic growth of CNTs from polypropylene byNi−Mo−Mg catalysts. The synthesized CNTs was characterized by Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffractometer (XRD), Raman spectroscopy, and Thermogravimetric analysis (TGA). Results show that the added rice husk carbon can take part in the formation of CNTs to a certain extent, and the trace of NH4Cl incorporated into rice husk carbon can significantly improve the conversion rate of polypropylene. The CNT products possess multiwalled structures and highgraphitization degrees. Finally, the prepared CNTs were investigated for the removal of methylene blue (MB) from water.

Electric field assisted mass production of carbon nanotubes on 303L stainless steel

To study the synthesis of carbon nanotubes, a premixed Propane/Air flame with inert co-flow was employed, along with a moderate direct current Electric Field to assess the effect on mass production and morphology of nanostructures yielded with electric bias. A supported bare plate of 303L stainless steel acted as substrate for the deposition of carbon nanostructures. Mass measurements were performed, and it was concluded that applying voltage to the substrate results in increase of mass produced. For the conditions tested, applying 30 V to the substrate proved to be the optimal situation regarding mass production improvements. It was observed that the average diameter decreases when voltage is applied to the substrate and that catalytic activity is enhanced. Temperature measurements and particle image velocimetry analysis lead to the conclusion that the presence of the electric field does not affect the mixture flow, improving the production via catalysis improvement. Moreover, the mechanism of mass growth rate revealed to be similar whether in the presence of voltage or not, and for the first time a monomolecular model was proposed for its description.

Analysis on the synthesis of vertically aligned carbon nanotubes: growth mechanism and techniques

This review article deals with orientation controlled growth of Carbon Nanotubes (CNTs). Vertically aligned CNTs (VACNTs) are considered as the best type of CNTs among all known forms. The present article covered various aspects required for the successful growth of orientation controlled CNTs especially vertically aligned form. We discussed in details about the important properties of VACNTs and the importance of VACNTs in materials science with relative applications. It included different types of CVD techniques which support the vertically aligned CNTs growth on the substrate and also supports its mass production with proper growth mechanism. We made a detailed discussion about catalyst engineering and different type of carbon sources. The catalyst lifetime is a key factor for growing long CNTs, so, the reason of catalyst poisoning and the protection of catalyst from poisoning is also a part of our article. We also explained in detail about the types of catalyst protector elements with their suitability on different temperature as well for different gases used for continuous growth of VACNTs, yarns of CNTs as well as bulk production of CNTs. We covered a broad study about the various catalysts, catalyst thickness and catalyst deposition techniques. The suitable supporting layers for different catalysts with their impacts on morphology as well as on the structure of as grown CNTs are also discussed. For reducing cost of VACNTs production, we included eco-friendly natural wastage materials for catalysts and as carbon precursor. It also included the process by which different designs and structures of VACNTs can be made specifically by bending of VACNTs during growth running time through the utilization of different catalyst reservoirs. The discussion made in present article on the growth of oriented CNTs will help to grow selective vertically aligned CNTs in the convenient way with economical rate and thereby helps in the mass production of CNTs.

Synthesis and comparison of different spinel ferrites and their catalytic activity during chemical vapor deposition of polymorphic nanocarbons

Chemical vapor deposition (CVD) is considered as a low-cost industrial technique for the mass production of carbon nanotubes (CNTs) which exhibit remarkable performance in various fields especially, in green technologies like, energy storage, green composites, solar cells etc. To optimize the yields, it is necessary to understand the role of different parameters affecting their production. In this research, the role of different spinel ferrites has been studied for the catalytic production of the CNTs with different morphologies (polymorphic nano carbons- PNCs) via CVD process. The characterization of the produced PNCs is done using X-ray diffraction, high-resolution Raman spectroscopy, field emission-scanning electron microscopy, and field emission-transmission electron microscopy. It is found that all the spinel ferrites behave differently during synthesis and produces different morphology of nanocarbons (tubes, fibers, beads etc.). Additionally, the thermal and magnetic properties of the produced PNCs are also compared through thermo-gravimetric analysis and vibrating sample magnetometer, respectively. It is found that all the samples show different thermal stability and weak ferromagnetic behavior.

Evaluation of Carbon Nanotubes Making Techniques

<p>After the initial discovery of Carbon Nanotubes in the Grime by electrical discharge, various methods have been developed to produce Carbon Nanotubes. In this study, four more conventional methods for producing Carbon Nanotubes have been evaluated. These include: Electrical arc discharge, Laser ablation, Sedimentation by chemical vapor and HIPco. The last method mentioned is highly regarded in the last few years and it have been produced the subject of many investigations in the field of Carbon Nanotubes. The results of this research show that HIPco production method has ability to supply mass production of Carbon Nanotubes in the future.</p>

Mapping differential cellular protein response of mouse alveolar epithelial cells to multi-walled carbon nanotubes as a function of atomic layer deposition coating

Carbon nanotubes (CNTs), a prototypical engineered nanomaterial, have been increasingly manufactured for a variety of novel applications over the past two decades. However, since CNTs possess fiber-like shape and cause pulmonary fibrosis in rodents, there is concern that mass production of CNTs will lead to occupational exposure and associated pulmonary diseases. The aim of this study was to use contemporary proteomics to investigate the mechanisms of cellular response in E10 mouse alveolar epithelial cells in vitro after exposure to multi-walled CNTs (MWCNTs) that were functionalized by atomic layer deposition (ALD). ALD is a method used to generate highly uniform and conformal nanoscale thin-film coatings of metals to enhance novel conductive properties of CNTs. We hypothesized that specific types of metal oxide coatings applied to the surface of MWCNTs by ALD would determine distinct proteomic profiles in mouse alveolar epithelial cells in vitro that could be used to predict oxidative stress and pulmonary inflammation. Uncoated (U)-MWCNTs were functionalized by ALD with zinc oxide (ZnO) to yield Z-MWCNTs or aluminum oxide (Al2O3) to yield A-MWCNTs. Significant differential protein expression was found in the following critical pathways: mTOR/eIF4/p70S6K signaling and Nrf-2 mediated oxidative stress response increased following exposure to Z-MWCNTs, interleukin-1 signaling increased following U-MWCNT exposure, and inhibition of angiogenesis by thrombospondin-1, oxidative phosphorylation, and mitochondrial dysfunction increased following A-MWCNT exposure. This study demonstrates that specific types of metal oxide thin film coatings applied by ALD produce distinct cellular and biochemical responses related to lung inflammation and fibrosis compared to uncoated MWCNT exposure in vitro.

Mass production of CNTs using CVD multi-quartz tubes

Carbon nanotubes (CNTs) have become the backbone of modern industries, including lightweight and heavy-duty industrial applications. Chemical vapor deposition (CVD) is considered as the most common method used to synthesize high yield CNTs. This work aims to develop the traditional CVD for the mass production of more economical CNTs, meeting the growing CNT demands among consumers by increasing the number of three particular reactors. All reactors housing is connected by small channels to provide the heat exchange possibility between the chambers, thereby decreasing synthesis time and reducing heat losses inside the ceramic body of the furnace. The novel design is simple and cheap with a lower reacting time and heat loss compared with the traditional CVD design. Methane, hydrogen, argon, and catalyzed iron nanoparticles were used as a carbon source and catalyst during the synthesis process. In addition, CNTs were produced using only a single quartz tube for comparison. The produced samples were examined using XRD, TEM, SEM, FTIR, and TGA. The results showed that the yield of CNTs increases by 287 % compared with those synthesized with a single quartz tube. Moreover, the total synthesis time of CNTs decreases by 37 % because of decreased heat leakage.

Simple and Precise Quantification of Iron Catalyst Content in Carbon Nanotubes Using UV/Visible Spectroscopy.

Iron catalysts have been used widely for the mass production of carbon nanotubes (CNTs) with high yield. In this study, UV/visible spectroscopy was used to determine the Fe catalyst content in CNTs using a colorimetric technique. Fe ions in solution form red–orange complexes with 1,10-phenanthroline, producing an absorption peak at λ=510 nm, the intensity of which is proportional to the solution Fe concentration. A series of standard Fe solutions were formulated to establish the relationship between optical absorbance and Fe concentration. Many Fe catalysts were microscopically observed to be encased by graphitic layers, thus preventing their extraction. Fe catalyst dissolution from CNTs was investigated with various single and mixed acids, and Fe concentration was found to be highest with CNTs being held at reflux in HClO4/HNO3 and H2SO4/HNO3 mixtures. This novel colorimetric method to measure Fe concentrations by UV/Vis spectroscopy was validated by inductively coupled plasma optical emission spectroscopy, indicating its reliability and applicability to asses Fe content in CNTs.

Mass Production of Carbon Nanotubes and its Future Applications: A Review

This paper reviews the mass production of carbon nanotubes via chemical vapor deposition method using conventional and bio-hydrocarbon precursors. Its applications in nanocomposite material and energy storage are also briefly reviewed.

Synthesis of Multi-walled Carbon Nanotubes from Glycine Max Oil and Their Potential Applications

The discovery of carbon nanotubes has created new era in the field of nanotechnology. Spectacular properties of these nanostructured materials, stimulating scientists to peep into this tiny tube with ever increasing curiosity. The immediate challenge is to produce desired structural and characteristic featured carbon nanotubes in large quantities. Chemical vapor deposition is the most popular method of producing carbon nanotubes and it is of low-cost and highly useful technique for mass production of carbon nanotubes. These efforts requires not only chosen technique but also based on the precursor and the catalytic support. Glycine max oil a botanical hydrocarbon, has been found to be effective precursor for the synthesis of multi-walled carbon nanotubes (MWNTs) by Spray Pyrolysis over well dispersed Fe /Mo catalyst supported on silica at 650 °C under Ar atmosphere. As-grown MWNTs were characterized by SEM, HRTEM, Raman spectroscopy and Nitrogen adsorption studies. Raman spectroscopy revels that MWNTs are well graphitized. Dynamic and equilibrium studies of adsorption of Basic brown-4 on MWNTs were also reported.

Continuous synthesis of carbon nanotubes using a metal-free catalyst by CVD

This study demonstrates the first example of the use of a metal-free catalyst for the continuous synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD). In this paper silica nanoparticles produced from the thermal decomposition of PSS-(2-(trans-3,4-Cyclohexanediol)ethyl)-Heptaisobutyl substituted (POSS) were used as catalyst and ethanol was served as both the solvent and the carbon source for nanotube growth. The POSS/ethanol solution was nebulized by an ultrasonic beam. The tiny mists were continuously introduced into the CVD reactor for the growth of CNTs. The morphology and structure of the CNTs have been investigated by scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The obtained CNTs have a multi-walled structure with diameters mainly in the size range from 13 to 16nm. Detailed investigations on the growth conditions indicate that the growth temperature and POSS concentration are important for achieving high-quality nanotubes, and that the existing of small amount of water in ethanol is effective to remove amorphous carbon species during the formation of CNTs. The mass production of CNTs without any metal contaminant will provide a chance for investing and understanding the intrinsic properties of CNTs and applications particularly in nanoelectronics and biomedicines.

Techno-economics of carbon nanotubes produced by open air arc discharge method

This paper describes a simplified arc discharge method for synthesis of multi-walled carbon nanotubes (MWNTs). In this method, a continuous and mass production of carbon nanotubes (CNTs) can be achieved with high purity and considerable yield. There is no need for costly setup of the synthesis of MWNTs and the multistep purification, which is needed to obtain high pure MWNTs. The morphology and structure of the CNTs produced were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X ray diffraction, Raman spectroscopy and Thermo gravimetric analysis (TGA). The cost analysis for the synthesis of MWNTs through this simplified method was done and compared with the existing commercial methods for CNT production. The production cost of the CNTs synthesized by this simplified method is $3/gm. On comparison, it is considered to be one of the most cost effective and commercially viable production methods for MWNTs. Keywords: Multi-walled Carbon nanotubes, X-ray diffraction, Scanning electron microscope, Transmission electron microscopy, Raman spectroscopy

Chemical Vapor Deposition of Carbon Nanotubes: A Review on Growth Mechanism and Mass Production

This review article deals with the growth mechanism and mass production of carbon nanotubes (CNTs) by chemical vapor deposition (CVD). Different aspects of CNT synthesis and growth mechanism are reviewed in the light of latest progresses and understandings in the field. Materials aspects such as the roles of hydrocarbon, catalyst and catalyst support are discussed. Many new catalysts and new carbon sources are described. Growth-control aspects such as the effects of temperature, vapor pressure and catalyst concentration on CNT diameter distribution and single- or multi-wall formation are explained. Latest reports of metal-catalyst-free CNT growth are considered. The mass-production aspect is discussed from the perspective of a sustainable CNT technology. Existing problems and challenges of the process are addressed with future directions.

Production of high quality carbon nanotubes for less than $1 per gram

AbstractIn this article, we report on the mass production of carbon nanotubes using a continuous production system based on a rotary tube furnace. At first, we have optimized the composition of the metallic nanoparticles. Bimetallic Fe2Ni and Fe2Co alloys exhibit higher catalytic activity than pure Fe, Co or Ni. Then, catalyst production process has been modified for the preparation of large quantity of catalyst with low aggregation suitable for large scale synthesis of CNTs. A production rate of about 1.2 kg per day has been achieved. This is yielding to a cost production of less than $1 per gram. Finally, we show that the CNTs growth can also be obtained on naturally occurring calcite support for further cost reduction of the synthesis. Quality of the CNTs produced has been established by measuring their mechanical properties using AFM. Young's modulus of the CNTs can be as high as the ideal value of 1 TPa. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

CVD Growth of Carbon Nanotubes and Nanofibers: Big Length and Constant Diameter

AbstractSummary: We report mass production of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) with relatively high length and aspect ratio. We synthesized carbon nanomaterials by chemical vapor deposition (CVD) of methane as the feeding gas on Fe/Mo nanoparticles that use alumina‐aerogel support. Alumina‐aerogel‐supported Fe/Mo catalyst was prepared using sol‐gel. Drying step performed using rotary evaporation and freeze‐drying. CVD was performed using a quartz tube furnace. Samples were analyzed using scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy.

Flame-synthesis limits and self-catalytic behavior of carbon nanotubes using a double-faced wall stagnation flow burner

Flame-synthesis limits of carbon nanotubes (CNTs) are measured using a double-faced wall stagnation flow (DWSF) burner that shows potential in mass production of CNTs. With nitrogen-diluted premixed ethylene–air flames established on the nickel-coated stainless steel double-faced plate wall, the limits of CNT formation are determined using field-emission scanning and transmission electron microscopies and Raman spectroscopy. Also, self-catalytic behavior of the synthesized CNTs is evaluated using the DWSF burner with a CNT-deposited stainless steel double-faced plate wall. Results show narrow fuel–equivalence ratio limits of multi-walled CNT (MWCNT)-synthesis at high flame stretch rates and substantially extended limits at low flame stretch rates. This implies that the synthesis limits are very sensitive to the fuel–equivalence ratio variation for the high stretch rate conditions, yielding a lot of impurities and soot rather than MWCNTs. The enhanced ratio of tube inner diameter to wall thickness of the MWCNTs synthesized using a CNT self-catalytic flame-synthesis process is observed, indicating that the quality of metal-catalytic, flame-synthesized MWCNTs can be much improved via the process. Thus, using a DWSF burner with the CNT self-catalytic process has potential in mass production of MWCNTs with improved quality.

An attempt to prepare carbon nanotubes by carbonizing polyphosphazene nanotubes with high carbon content

Polyphosphazene nanotubes with about 20 nm in inner diameter and 100–200 nm in outer diameter were fabricated easily and then carbonized at 800 °C in a nitrogen atmosphere. Scanning electron microscopy and transmission electron microscope results showed that the bulk morphology of polyphosphazene nanotubes was retained after carbonization. The carbon content of the carbonized samples reached 93.28%. X-ray diffraction and Raman spectrum showed that the carbonized samples had low graphitization state. The present method can be used for a mass production of carbon nanotubes.

The mass production of carbon nanotubes using a nano-agglomerate fluidized bed reactor: A multiscale space–time analysis

The scaled-up mass production of carbon nanotubes (CNTs) was reviewed by a multiscale analysis from the delicate catalyst control needed at the atomic level, CNT agglomerate formation at the mesoscopic scale, to the continuous mass production process on the macroscopic scale. A four level analysis that considered CNT assembly, agglomerate structure, reactor hydrodynamics and coupled processing was used. Atomic scale catalyst design concepts were used to modulate the CNT structure. On the reactor scale, the design consideration was on getting suitable CNT and catalyst agglomerates with good fluidization behavior and transport properties. A pilot plant with high yield (15 kg/h) and purity (> 99.9%) was demonstrated, which made a great stride for extensive applications of CNTs. Other nano-agglomerate structures can also be considered using the multiscale time and space analysis, which will benefit mass production and applications of nanomaterials in future.

Quality classification via Raman identification and SEM analysis of carbon nanotubebundles using artificial neural networks

One of the major obstacles for successful mass production of carbon nanotubes (CNTs) isperforming quick and precise characterization of the properties of a given batch ofnanotubes. In this paper, we have identified a set of intermediate steps that will lead to acomprehensive, scalable set of procedures for analyzing nanotubes. The proposedmethodology was originated with data processing of Raman spectra of multi-wall carbonnanotubes (MWCNT) turfs and image enhancement of SEM micrographs. Image analysistechniques of SEM images were employed and stereological relations were determinedfor SEM images of CNT structures; these results were utilized to estimate themorphology of the turf (i.e. CNTs alignment and curvature) using an artificialneural networks (ANN) classifier. This model was also used to investigate the linkbetween Raman spectra of CNTs and the quality of the turf morphology. Thisnovel methodology will improve our capability to control the quality of the grownnanotubes through the use of this system in a supervised growth environment.

Engineered carbon nanoparticles alter macrophage immune function and initiate airway hyper-responsiveness in the BALB/c mouse model

With the mass production of fullerenes currently underway, and the mass production of carbon nanotubes soon to follow, only a few studies have examined the biological consequences of manmade nanoparticle exposure in the mammalian system. This study examines carbon nanoparticle (CNP) exposure in both in vitro (murine BALB/c alveolar macrophages) and in vivo (murine BALB/c intranasal instillations) systems. Three types of CNP were examined (single-walled nanotubes, multi-walled nanotubes, and C60 fullerenes). In vitro macrophage experiments included measurements of morphology changes, apoptosis, viability, and antigen-presenting cell function in response to CNP exposure. In vivo mouse experiments determined the inflammatory potential of CNP exposure in the lung using a BUXCO™ apparatus along with cell differentials and cell morphology. This study presents evidence that CNP, accumulated in the plasma membranes of cells (disrupting lipid rafts), increased alveolar macrophage function with regard to antigen-presentation, significantly exacerbated airway hyper-responsiveness, and caused an influx of macrophages into the lung by posited mechanisms that involve the unique molecular and physical properties of CNP.