Formation Of Carbon Nanostructures Research Articles

Sustainable Modification of Naturally Available Resources for Metal-Ion Storage Applications

The adoption of naturally abundant resources for energy storage applications represents a pivotal strategy in advancing large-scale sustainable green energy solutions across diverse sectors. This presentation provides an overview of E2MC's approaches to the green modification of naturally occurring materials at a low cost, focusing on their metal-ion energy storage capabilities. Key natural materials discussed include molybdenum disulfides (MoS2), ilmenite and natural graphite minerals, as well as corn waste. (a) The thermal oxidation of MoS2 is explored as a straightforward and effective method to produce layer-structured molybdenum trioxide (α-MoO3) with crystalline defects, showing enhanced Li-ion storage kinetics. The molten salt treatment of MoS2 produces sodium dimolybdate with improved Li-ion and Na-ion storage performances. Additionally, a hybrid nanostructure comprising metastable monoclinic molybdenum trioxide (β-MoO3), hexagonal MoS2 secondary crystals and graphene nanosheets is produced through mechanochemical-molten salt treatment. This hybrid structure exhibits an interesting Li-ion storage performance. (b) Carbonization of largely available corn lignocellulosic waste in the presence of molten salt is discussed as a facile approach for the preparation of biocarbons with appropriate specific surface area, pore volume, and elemental carbon purity. The partial dissolution of biomass impurities into the molten salt enhances the Li-ion and Na-ion storage performance of the biocarbon. Additionally, the treatment of corn-derived silica with Fe2O3 and graphite-derived graphene nanosheets, leads to the preparation of a nanostructure in which ferric oxide particles are coated with iron silicate, and these hybrid nanostructures are integrated with graphene nanosheets, showcasing an interesting Li-ion storage performance. (c) Efficient exfoliation of naturally available graphite minerals in molten salt is introduced leading to the formation of carbon nanostructures with promising applications in both Li-ion and Na-ion storage. The economic and strategic advantages associated with utilizing such naturally available resources for energy storage applications are also discussed. References W. Zhu, A.R. Kamali*, J. Alloy Compd. 932 (2023) 167724W. Zhu, A.R. Kamali*, J Alloy Compd. 968 (2023) 171823A.R. Kamali*, H. Zhao, J. Alloy Compd. 949 (2023) 169819W. Zhu, A.R. Kamali*, J. Alloy Compd. 831(2020) 154781H. Zhao, A. Rezaei, A.R. Kamali*, J. Electrochem. Soc. 169 (2022) 054512A.R. Kamali*, J. Ye, Miner. Eng. 172 (2021) 107175S. Li, A.R. Kamali*, Chem. Eng. Sci. 265 (2023) 118222S. Li, A.R. Kamali*, Gels 9 (2023) 701S. Li, A.R. Kamali*, Colloids Surf. A 656 (2023) 130275H. Fu, A.R. Kamali* et al, Chem. Eng. J. (2023) 146936W. Zhu, A.R. Kamali*, J. Electrochem. Soc. 168 (2021) 046517

Spark-Discharge-Activated 3D-Printed Electrochemical Sensors.

3D printing technology is a tremendously powerful technology to fabricate electrochemical sensing devices. However, current conductive filaments are not aimed at electrochemical applications and therefore require intense activation protocols to unleash a suitable electrochemical performance. Current activation methods based on (electro)chemical activation (using strong alkaline solutions and organic solvents and/or electrochemical treatments) or combined approaches are time-consuming and require hazardous chemicals and dedicated operator intervention. Here, pioneering spark-discharge-activated 3D-printed electrodes were developed and characterized, and it was demonstrated that their electrochemical performance was greatly improved by the effective removal of the thermoplastic support polylactic acid (PLA) as well as the formation of sponge-like and low-dimensional carbon nanostructures. This reagent-free approach consists of a direct, fast, and automatized spark discharge between the 3D-electrode and the respective graphite pencil electrode tip using a high-voltage power supply. Activated electrodes were challenged toward the simultaneous voltammetric determination of dopamine (DP) and serotonin (5-HT) in cell culture media. Spark discharge has been demonstrated as a promising approach for conductive filament activation as it is a fast, green (0.94 GREEnness Metric Approach), and automatized procedure that can be integrated into the 3D printing pipeline.

Carbon nanostructures synthesis by catalyst-free atmospheric pressure plasma jet

In this study, carbon nanostructures were synthesized utilizing a warm plasma jet at atmospheric pressure in a continuous and catalyst-free process. The procedure and apparatus were designed and constructed in our laboratory. Plasma was generated with 600 W of electrical energy, using a high-voltage, high-frequency alternating current power source. The working gas utilized was a propane/butane mixture, with a concentration ratio of 60:40, respectively. A production rate of 300 mg min−1 of powdered material was achieved, with a particle size between 20 and 100 nm. The product was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. Results show the formation of multilayer carbon nanostructures with a low content of functional groups; the obtained material presented structural defects and amorphous carbon. This work demonstrates that, with adequate control, warm plasma jet discharges can be employed for the synthesis of carbon nanostructures. The process is scalable and can be utilized for hydrocarbon reforming and hydrogen production. However, further studies are needed to improve the quality of the nanostructures and process efficiency. The synthesized material can potentially be used in gas adsorption or in the manufacture of polymeric nanocomposites with enhanced thermal, electrical, and mechanical properties.

CARBON NANOSTRUCTURES OBTAINING FROM POLYMER MATERIALS

As part of the expansion of raw material base used in the development of technological and productive methods for the synthesis of carbon nanostructures (CNS) and solving the problem of environmentally friendly and economical polymer recycling, the results of investigation of microwave (MW) catalytic pyrolysis of macromolecular compounds from the range of polystyrene, polypropylene, polyethylene terephthalate, polyvinyl alcohol are presented. The information about existing approaches to solving these problems is briefly considered, and the prospects for MW processing of polymers are shown. The process was carried out by microwave treatment of a mixture of polymer raw materials acting as a carbon donor and substances-precursors of metal catalysts – cobalt and nickel compounds, their mixtures, as well as metal iron and nickel. Graphite and carbon fiber were used as temperature regulator. Experiments have demonstrated that effective conversion of the studied compounds occurs only in the presence of MW energy absorbers-converters, regardless of the nature of metal catalyst precursor. According to electron microscopy data, the resulting materials are a mixture of carbon nanostructures of disordered morphology with the predominant content of carbon nanotubes (CNTs) in the reaction products for experiments with polystyrene, polypropylene and polyethylene terephthalate. The use of polypropylene and polyvinyl alcohol leads to the production of carbon nanostructures containing only a small amount of CNTs. X-ray phase analysis data confirm the formation of multi-walled carbon nanotubes as the main structural component of the obtained carbon nanomaterials. It has been suggested that transformation pathways of the investigated hydrocarbons are similar, despite the difference in pyrolysis temperatures, which may be related to the simultaneous processes of polymer cracking, carbonization of decomposition products and CNS synthesis due to the rapid growth of reaction mass temperature during microwave treatment. The efficiency of different precursors of catalytic systems based on transition metals in the processes examined is substantiated. It has been shown that the high carbon content in feedstock promotes the formation of carbon nanostructures, but is not decisive for carbon nanotubes obtaining. For citation: Zaritovskii A.N., Kotenko E.N., Grishchuk S.V. Carbon nanostructures obtaining from polymer materials. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 99-106. DOI: 10.6060/ivkkt.20246705.6957.

Microarchitectured and nanoscale hierarchical structures of carbon in ancient archaeological carburisation slags

The famed Wootz steels are hypothesized to contain carbon nanotubes. However, the primary context of such nanostructures in Wootz steels is not known. In this letter, we present the microarchitectured and nanoscale hierarchical carbon structures in ancient archaeological carburization slags from 400 BCE to 16th century CE. We show that carbon microrods at the micro-scale are composed of finer carbon microrods, which are arranged in a co-axial manner. Carbon microrods are composed of twisted carbon nanotubes at the nanoscale. Such carbon nanostructure formation in the crucible process provides the possible source of carbon nanostructures in crucible steels of antiquity.

Fabrication Method of Carbon-based Materials in CH4/N2 Plasma by RF-PECVD and Annealing Treatment for Laser Diodes

The present research addresses the synthesis of carbon materials thin films by RF-PECVD in N2/CH4 gas mixture. Carbon materials film was formed at 40/48 sccm of CH4/N2 of the total gas flow rate ratio CH4/CH4+N2 = 0.45 and 200/100 W HF/LF power at a deposition temperature of 350 oC and 1000 mTorr pressure. Then, post-annealing of carbon materials film took place at 400 oC by means of RTA under N2 flow. The formation of carbon nanostructures was investigated by scanning electron microscopy, energy dispersive X-ray, Raman spectroscopy, and atomic force microscopy, respectively. AFM shows that the films consisted of nanocrystalline grains. The surface morphology and structural characteristics of materials were studied as a gas flow function and substrate temperature. EDX results indicated the carbon presence, and Raman spectroscopy analysis revealed two broad bands: D-band 1381.64 cm−1 and G-band 1589.42 cm−1. The temperature-dependent post-annealing of carbon materials plays a key role in the graphite crystallites growth at high substrate temperatures. Our results indicate carbon materials incorporation for laser diode applications.

Modeling and characterization of the nucleation and growth of carbon nanostructures in physical synthesis

Carbon nanostructures formed through physical synthesis come in a variety of sizes and shapes. With the end goal of rationalizing synthetic pathways of carbon nanostructures as a function of tunable parameters in the synthesis, we investigate how the initial density and quench rate influence the morphology of carbon nanostructures obtained from the cooling of a gas of atomic carbon by molecular dynamics simulations. For the structural analysis, we combine classical order parameters with a data-driven approach based on local density descriptors and kernel similarity measurements. Aided by this complementary set of tools, we describe in detail the formation of carbon nanostructures from the gas phase. Their formation proceeds through the nucleation of small liquid carbon nanoclusters followed by growth into unique objects. We find that ordered structures can only be obtained at certain quenching rates and that among those, fullerene-like particles are favored at intermediate densities while nanotubes-like structures require higher initial densities. © XXXX CEA. Elsevier

Carbon nanofiber growth from methane over carbon-supported NiCu catalysts: Two temperature regimes

An alternative route towards COx-free production of hydrogen is the thermal catalytic decomposition of methane. In addition to hydrogen, valuable carbon nanomaterials can be formed. Carbon nanofiber formation from methane decomposition over carbon supported NiCu catalysts was studied in-situ using a Thermogravimetric analyzer. We especially investigated how the carbon yield is influenced by reaction parameters. Based on experiments with varying temperature (450–600 °C), two distinct temperature regimes were identified. Different kinetic parameters were derived for the two regimes. Activation energies of 86 and 45 kJ/mol, and reaction orders in methane of close to 1 and 1.5, were found in the low and high temperature regimes, respectively. We postulate that at lower temperature the methane dissociation is rate limiting, while at higher temperature the carbon formation plays a more critical role. At low temperatures mostly full fishbone fibers are formed, whereas at higher temperatures mainly hollow fibers are formed. The maximum carbon yield is obtained at the transition between the two regimes, when the carbon supply and carbon nanostructure formation are balanced.

Влияние предварительной термической обработки на морфологию углеродного слоя, формирующегося на поверхности хлорированного поливинилхлорида при воздействии мощного ионного пучка

The effect of preliminary heat treatment on the morphology of carbon layer formed on the surface of chlorinated polyvinyl chloride with the addition of ferrocene (10 % of polymer weight) under the impact of a high-power nanosecond-durable ion beam has been studied. Preliminary exposure of samples in an oven at different temperatures for 1 hour leads to partial dehydrochlorination of the surface layer of the polymer film and interchain crosslinking, creating centers for the start of the carbonization reaction, and thus affects the formation of carbon nanostructures during subsequent irradiation with a high-power ion beam. The possible mechanism of carbon nanostructures formation from chlorinated polyvinyl chloride under the impact of a high-power ion beam and the mechanism of the influence of preliminary heat treatment on it are considered. It has been established that different heat treatment temperatures lead to different morphologies of the resulting carbon nanostructures. On the control sample and the sample subjected to heating to 100 °C, only nanofibers are formed, preheating to 150 °C leads to the formation of a porous structure with nanosized pores under the nanofibers, and preheating to 200 °C leads to a significant decrease in the porosity and concentration of nanofibers.

Experimental and theoretical study of the conditions for the formation of carbon nanostructures in an arc discharge in helium, argon and nitrogen

Experimental measurements and numerical simulation of plasma parameters of an electric arc discharge in helium, argon, and nitrogen media at pressures of 25 Torr were carried out. On the basis of a theoretical model and experimental data on the interelectrode distance and the rate of sputtering of the anode, the radial distribution of the gas temperature is calculated. The obtained distribution is consistent with measurements carried out using a probe with a thermocouple, and the residence times of the sputtered material in different temperature ranges are determined. The properties and morphology of soot synthesized on the chamber walls were investigated by HRTEM, XRD and TGA methods. It is shown that during an arc discharge in nitrogen, the maximum number of graphite structures arises as a result of a longer residence of the sputtered carbon particles arising in the process at temperatures of about 700 –1700°C.

Spontaneous formation of uniform 1D/2D amorphous carbon nanostructures upon fracture of CNT-concentrated ceramics

Uniform 1D/2D amorphous carbon nanostructures were discovered to spontaneously form on the fracture surfaces of carbon nanotube-concentrated ceramic composites upon their static fracture. The factors potentially responsible for the formation, thickness and detectability of such nanosized amorphous carbon structures are discussed. Ultimately, a mechanism for their formation upon fracture is proposed. The present discovery could help to avoid misinterpretation of the carbon/matrix interfacial strength, reactions and the composites reinforcing mechanism especially in carbon-concentrated composite systems. Furthermore, this is the first report on the formation of amorphous carbon nanostructures upon fracture of a carbon-based composite material.

Perspectives of the Formation of Carbon Nanostructures from Biomass Gasification Tar Compounds─A Mini-Review

Perspectives of the Formation of Carbon Nanostructures from Biomass Gasification Tar Compounds─A Mini-Review

Shock processing of amorphous carbon nanodust

Our understanding on the role of amorphous carbon in the interstellar medium to form complex structures, such as carbon nanotube/graphene/fullerene, is limited to date. We have investigated how shocks may induce physico-chemical transformation in amorphous carbon by subjecting samples of carbon nanopowder to high-temperature shocks, ∼7300 K, in a hydrogen-free environment for about 2 ms using a shock tube. The shock conditions achieved in the laboratory mimics low velocity interstellar shocks. Post shock samples were analyzed using Raman Spectroscopy and High Resolution – Transmission Electron Microscopy. We have found compelling evidence for the formation of carbon nanotube, graphene, and various other carbon nanostructures induced by the shock. Our results show that shocks in the interstellar medium can provide important chemical pathways to the formation of fullerenes and suggests that other carbonaceous structures may be present as well.

Nanodiamonds from Fuel

In this paper, we present the results of the synthesis of nanodiamonds from carbon nanostructures and diamondoids in an arc discharge. The electrodes used in the experiments were a molybdenum cathode and a copper anode coated with carbon nanostructures such as carbon nanotubes and diamondoids. The formation of carbon nanostructures on the surface of a copper electrode was carried out in an electric arc sunk into fuel oil. At the next stage, these carbon nanostructures served as a source of atomic carbon and diamondoids from the surface of the arc discharge anode. The use of fuel oil as a feedstock for creating the electrode material probably led to the retention of diamondoids contained in fuel oil during two vaporizations. It was found that, in addition to carbon nanotubes, nanodiamonds also formed on the cathode surface.

Scaling up the Process of Catalytic Decomposition of Chlorinated Hydrocarbons with the Formation of Carbon Nanostructures

Catalytic processing of organochlorine wastes is considered an eco-friendly technology. Moreover, it allows us to obtain a value-added product—nanostructured carbon materials. However, the realization of this process is complicated by the aggressiveness of the reaction medium due to the presence of active chlorine species. The present research is focused on the characteristics of the carbon product obtained over the Ni-Pd catalyst containing 5 wt% of palladium in various quartz reactors: from a lab-scale reactor equipped with McBain balance to scaled-up reactors producing hundreds of grams. 1,2-dichloroethane was used as a model chlorine-substituted organic compound. The characterization of the materials was performed using scanning and transmission electron microscopies, Raman spectroscopy, and low-temperature nitrogen adsorption. Depending on the reactor type, the carbon yield varied from 14.0 to 24.2 g/g(cat). The resulting carbon nanofibers possess a segmented structure with disordered packaging of the graphene layers. It is shown that the carbon deposits are also different in density, structure, and morphology, depending on the type of reactor. Thus, the specific surface area changed from 405 to 262 and 286 m2/g for the products from reactor #1, #2, and #3, correspondingly. The main condition providing the growth of a fluffy carbon product is found to be its ability to grow in any direction. If the reactor walls limit the carbon growing process, the carbon product is represented by very dense fibers that can finally crack the reactor.

Numerical modelling of non-premixed biogas and LPG combustion to study carbon nanostructures formation in flame

This work presents the numerical simulation of biogas and LPG fuelled diffusion flames in an axisymmetric chamber to study in-depth, the formation mechanism of soot and carbon nanostructures in these flames. The simulation is formulated on the set of transport equations that involve the equations for conservation of mass (the continuity equation), momentum (Navier-Stokes equation), energy, and chemical species. The governing equations are solved using ANSYS FLUENT, which is centered on the finite volume method. To predict the soot formation, one step soot model has been incorporated. The solution of these equations permits the estimation of temperature field and species concentrations inside the flame. Simulation is conducted at fixed fuel flow rate and varied oxygen flow rates. The results reveal that the formation of soot and carbon nanostructures is strongly dependent on peak flame temperature and concentration of precursor species formed in the flame. Since two fuels produce an exclusive chemical environment in the flame, the flame temperature and CO concentration that is conducive to the growth of carbon nanostructures is higher for LPG fuel as compared to that for biogas. Hence, the nucleation process of carbon nanostructures is faster for LPG than biogas. Moreover, the reactions taking place inside the flame at different locations can also be predicted from flame temperature and species concentration at that location. Pyrolysis of fuel occur near the burner exit, followed by the nucleation and surface growth of carbon nanostructures in the nearby region and oxidation of formed carbon nanostructures near the flame tip.

Formation of carbon nanostructures on nickel acetate alcogel by CVD method and its OER electrocatalytic study in alkaline media

Formation of carbon nanostructures on nickel acetate alcogel by CVD method and its OER electrocatalytic study in alkaline media

Carbon Nanostructures Derived through Hypergolic Reaction of Conductive Polymers with Fuming Nitric Acid at Ambient Conditions.

Hypergolic systems rely on organic fuel and a powerful oxidizer that spontaneously ignites upon contact without any external ignition source. Although their main utilization pertains to rocket fuels and propellants, it is only recently that hypergolics has been established from our group as a new general method for the synthesis of different morphologies of carbon nanostructures depending on the hypergolic pair (organic fuel-oxidizer). In search of new pairs, the hypergolic mixture described here contains polyaniline as the organic source of carbon and fuming nitric acid as strong oxidizer. Specifically, the two reagents react rapidly and spontaneously upon contact at ambient conditions to afford carbon nanosheets. Further liquid-phase exfoliation of the nanosheets in dimethylformamide results in dispersed single layers exhibiting strong Tyndall effect. The method can be extended to other conductive polymers, such as polythiophene and polypyrrole, leading to the formation of different type carbon nanostructures (e.g., photolumincent carbon dots). Apart from being a new synthesis pathway towards carbon nanomaterials and a new type of reaction for conductive polymers, the present hypergolic pairs also provide a novel set of rocket bipropellants based on conductive polymers.

Fullerene production management system used for creation of hydrated solutions

The use of hydrated solutions of fullerene C60 in the food industry is considered. The features of the synthesis of fullerenes C60 by the method of plasma evaporation of graphite raw materials are presented. The structure of a complex mathematical model is proposed which allows one to relate the process of the formation of carbon nanostructures (CNS) in a plasma with the synthesis conditions, which allows one to determine the process conducting conditions with the maximum yield of the final product. An automated information management system (AIMS) for the production of fullerenes has been developed, which allows, based by numerical calculations using a complex mathematical model, to determine rational technological parameters for the graphite raw materials used and the synthesis method. The architecture of an automated information system for managingthe synthesis of carbon nanostructures is presented. The description of the interaction modules and subsystems of the control system is given. The scheme of interaction of elements of an automatedinformation management system in the process of collecting and processing information is presented. The developed automated information management system allows you to control the process of synthesis of carbon nanostructures in automatic or manual mode, monitor technological parameters in real time, calculate control actions and stabilize parameters, process the received data and present it to the user in the form of tabular or graphical information.

Формирование металл-углеродных нанокомпозитов на основе наночастиц сплава Cu-Fe и карбонизированного полиакрилонитрила

A method for the synthesis of nanoparticles of the Cu-Fe bimetallic system with limited mutual solubility of the components is proposed. The synthesis method consists of a one-stage process of IR pyrolysis of precursors in the form of films obtained from a joint solution of polyacrylonitrile and hydrates-nitrates of iron and copper. The effect of the synthesis temperature on the structure formation of the nanocomposites and the phase composition of bimetallic Cu-Fe nanoparticles dispersed in the carbon matrix was studied. The analysis showed a simultaneous presence of Fe and Cu phases in nanocomposites, presumably with a low solubility of the components. The average particle size is 14-17 nm and changes insignificantly with an increase in the synthesis temperature from 400 to 700°C. An increase in the synthesis temperature to 800°C led to a broadening of the particle size distribution and the increase in the average size. The formation of complex carbon nanostructures on Cu-Fe nanoparticles is found.