Carbon Nano-onions Research Articles

Ferromagnetically filled carbon nano-onions: the key role of sulfur in dimensional, structural and electric control.

A key challenge in the fabrication of ferromagnetically filled carbon nano-onions (CNOs) is the control of their thickness, dimensions and electric properties. Up to now literature works have mainly focused on the encapsulation of different types of ferromagnetic materials including α-Fe, Fe3C, Co, FeCo, FePd3 and others within CNOs. However, no report has yet shown a suitable method for controlling both the number of shells, diameter and electric properties of the produced CNOs. Here, we demonstrate an advanced chemical vapour deposition approach in which the use of small quantities of sulfur during the pyrolysis of ferrocene allows for the control of (i) the diameter of the CNOs, (ii) the number of shells and (iii) the electric properties. We demonstrate the morphological, structural, electric and magnetic properties of these new types of CNOs by using SEM, XRD, TEM, HRTEM, EIS and VSM techniques.

Performance Evaluation of Cutting Fluids with Carbon Nano-Onions as Lubricant Additives

In machining of high precision automotive parts, the dimensional variation of the cutting process is very critical. The demand for high quality and fully automated production places a lot of emphasis on the cutting process, which has a major contribution to part quality. Cutting fluid has been a key factor to machining performance and a key contributor to increase the effectiveness of machining systems. In this way, cutting fluids play an important role in minimizing production time, cost, and energy in different machining operations. Maintaining and operating the cutting fluid supplies is a huge cost driver and an environmental challenge. Carbon onion nanoparticles have been successfully developed with high tribology performance and mixed in metalworking fluids (MWF) to improve the performance of the fluids. Even though the trend has been to use less MWF, which is dry or MQL whenever possible, MWF are still utilized in large volumes. The literature has reported several cases of very successful use of nanofluids in machining operations for various tough-to-machine materials. To enhance the coolant, nanoparticles such as carbon nano-onions are mixed in the oil and water-based MWF. The paper presents the results from several tests performed during the evaluation of the above nanoparticles in oil and water based cutting fluids in machining processes.

Hybridization Effects of Nitrogen-Doped Graphene–Carbon Nanotubes and Nano-Onion Carbons on the Electrocatalytic Activity of the Oxygen Reduction Reaction

Nitrogen-doped graphene–carbon nanotubes (NG-NCNTs) were prepared from multi-walled carbon nanotubes (MWCNTs) and then hybridized with nitrogen-doped nano-onions (NNOs) to fabricate a highly effective carbon-based electrocatalytic material for the oxygen reduction reaction (ORR). The graphene oxide attached on the oxidized MWCNTs (GO-OCNTs), which was formed from the MWCNTs by an oxidation reaction with a strong acid, underwent nitrogen doping with urea to produce the NG-NCNTs. The content of oxygen of the GO-OCNTs was controlled by varying the oxidation time to produce NG-NCNTs with an optimal ORR activity. The NG-NCNTs prepared from GO-OCNTs and oxidized for 6 h showed the best ORR activity. The NG-NCNTs were hybridized with NNOs to further improve their ORR activity. The NNO aggregates were well dispersed among the NG-NCNTs by mixing, and significantly increased the specific surface area of the NG-NCNT/NNO hybrid. As a result, the NG-NCNT/NNO hybrid exhibited a better ORR activity than the NNOs and NG-NCNTs. The current density of the NG-NCNT/NNO hybrid was comparable to that of the platinum-based catalyst (Pt/C). A carbon-based catalyst with a high ORR activity and long-term stability could be produced by hybridizing NG-NCNTs and NNOs.

F-Doped carbon nano-onion films as scaffold for highly efficient and stable Li metal anodes: a novel laser direct-write process.

Li metal is the most promising choice for anode in high-energy rechargeable batteries, but the dendrite growth upon cycling leads to safety concerns and poor cycle life. Herein, we demonstrate a novel and scalable approach for direct writing of a thin layer of carbon nano-onions on copper substrate to stabilize the Li metal anode and prevent the dendrite growth. The F-doped carbon nano-onion film (F-CNOF) scaffold enables reversible electroplating for over 1500 hours (300 cycles) with a coulombic efficiency of ∼100%. The F-CNOF is capable of depositing Li equivalent to a capacity of 10 mA h cm-2 (gravimetric capacity 3218 mA h g-1) at 1 mA cm-2, operating at a high current density of 6 mA cm-2. More importantly, these features of long-term cyclic stability and excellent rate capability are attributed to the very high curvature due to nano dimension (∼108 m-1) of the nano-onions that develop a very uniform Li flux due to the negative surface charge, thus preventing the dendrite formation. We have also shown via first-principles DFT calculations that the high curvature achieved herein can significantly enhance the binding energy of Li to the carbon surface, which helps to improve lithiophilicity. A full cell fabricated using Li4Ti5O12 as the positive electrode showed cyclic stability of 450 cycles.

On the morphological, structural and electrochemical properties of entangled Cu-filled carbon nano-onions.

In this work we demonstrate an advanced chemical vapour synthesis approach in which the synthesis of Cu-filled carbon nano-onions (CNOs) is achieved by direct sublimation and pyrolysis of a not previously used precursor, namely chloro(1,5-cyclooctadiene)copper(i) dimer. The cross-sectional morphology and filling-ratio of the as grown CNOs were characterized by detailed transmission electron microscopy (TEM), high resolution TEM analyses, Fourier transform and lattice profile analyses. The structural graphitic arrangement and electronic properties of the CNOs were then investigated by means of X-ray diffraction and absorption spectroscopy. The electrochemical impedance spectroscopy and cyclic voltammetry of presented structures were also investigated and reveal a high electrical resistance. Finally the electrochemical performances of this type of CNOs were compared with those of another type of CNOs filled with different metal-carbide materials.

UV absorption investigation of ferromagnetically filled ultra-thick carbon onions, carriers of the 217.5 nm Interstellar Absorption Feature

Carbon nano-onions (CNOs) are fullerene-like structures which consist of quasi-spherical closed carbon shells. These structures have become a subject of great interest thanks to their characteristic absorption feature of interstellar origin (at 217.5 nm, 4.6 μm−1). An additional extinction peak at 3.8 μm−1 has also been reported and attributed to absorption by graphitic residues between the as-grown CNOs. Here, we report the ultraviolet absorption properties of ultra-thick CNOs filled with FePt3 crystals, which also exhibit two main absorption peaks—features located at 4.58 μm−1 and 3.44 μm−1. The presence of this additional feature is surprising and is attributed to nonmagnetic graphite flakes produced as a by-product in the pyrolysis experiment (as confirmed by magnetic separation methods). Instead, the feature at 4.58 μm−1 is associated with the π-plasmonic resonance of the CNOs structures. The FePt3 filled CNOs were fabricated in situ by an advanced one-step fast process consisting in the direct sublimation and pyrolysis of two molecular precursors, namely, ferrocene and dichloro-cyclooctadiene-platinum in a chemical vapour deposition system. The morphological, structural, and magnetic properties of the as-grown filled CNOs were characterized by a means of scanning and transmission electron microscopy, X-ray diffraction, and magnetometry.

Revealing the formation mechanism of ultrahard nanotwinned diamond from onion carbon

Controlled nanotwinning is an effective way to enhance the mechanical properties of materials. Recent discovery of nanotwinned diamond converted from carbon nano-onions with high-density defects reveals that the presence of nanotwinned structures can increase the hardness of the product to exceed that of natural diamond by a surprisingly large margin. To understand the mechanism of nanotwinning, the microscopic transformation pathway from carbon nano-onions to nanotwinned diamond was investigated in the present study. We carried out a direct high-pressure high-temperature synthesis of nanotwinned diamond from onion carbon without high-density defects. The obtained nanotwinned diamond possesses an exceptionally high Vickers hardness of 215 GPa at 4.9 N. The transformation path was analyzed using aberration-corrected transmission electron microscopy (TEM) which suggests a martensitic process strongly influenced by the pressure-temperature conditions. Specifically, the appearance of {111} nanotwinned structure and stacking faults was determined by the characteristics of the onion shells, while the accumulation of the stress due to the sliding of the shells cause the crystal to re-align along the shear direction. These findings not only clarify the direct transformation mechanism from onion-like precursors to nanotwinned diamond, but also have broad implications for further exploration of new materials with exceptional properties.

Toxicity Assessment of Carbon Nanomaterials in Zebrafish during Development.

Carbon nanomaterials (CNMs) are increasingly employed in nanomedicine as carriers for intracellular transport of drugs, imaging probes, and therapeutics agents, thanks to their unique optical and physicochemical properties. However, a better understanding about the effects of CNMs on a vertebrate model at the whole animal level is required. In this study, we compare the toxicity of oxidized carbon nano-onions (oxi-CNOs), oxidized carbon nano-horns (oxi-CNHs) and graphene oxide (GO) in zebrafish (Danio rerio). We evaluate the possible effects of these nanomaterials on zebrafish development by assessing different end-points and exposure periods.

Single‐Walled Carbon Nanotubes Shock‐Compressed to 0.5 Mbar (Phys. Status Solidi B 11/2017)

Single-walled carbon nanotubes (SWCNTs) have been dynamically (shock) compressed to 0.5 Mbar, above the limit of their structural integrity. Two distinct types of material are identified by high-resolution transmission electron microscopy (HRTEM) and multi-wavelength Raman spectroscopy in the sample recovered after shock: multi-layer graphene (MLG) and a two-phase material composed of nano-clustered graphene and amorphous carbon whereas no diamond-like carbon or carbon nano-onions are found. Peak decomposition of the Raman spectra was used to estimate the coherent scatterers (clusters) size in MLG at 36 nm from the D- to G-band intensity ratio dependence on the photon excitation energy. Botella et al. (article no. 1700315) propose the peak fitting model for decomposition of the Raman spectra of highly disordered carbon material containing graphene nano-clusters and stress the importance of accounting for heptagonal- and pentagonal-ring defects in graphene layers for the analysis of such spectra. The cover image shows HRTEM images and the correspondent Raman spectra of the two types of material along with peak decomposition of the two-phase material with the peaks assigned to heptagons (a) and pentagons (b). Particulars of the SWCNTs transformation to other structural forms of carbon at high pressure/temperature are discussed.

PEGylated Carbon Nano-onions Composite as a Carrier of Polyphenolic Compounds: A Promising System for Medical Applications and Biological Sensors

Natural polyphenols and their composites display a wide range of biological activities. Therefore, they are extensively studied in terms of biological and medical applications. An example is 1,2,3,4,6-penta-β-O-galloyl-d-glucopyranose (β-PGG), a glycoside that is known to exert numerous protective effects on mammalian cells. Moreover, it is a strong antibacterial compound. Herein, we analysed the potential application of a composite composed of carbon nano-onions (CNOs) and polyethylene glycole (PEG 400) as a carrier of β-PGG. Bioaccessibility of the glycoside and gallic acid (GA) was assessed with surface plasmon resonance spectroscopy (SPR) to study the interaction of β-PGG and GA with a synthetic triple helical collagen-like peptide.

Membrane-assisted assembly strategy of flexible electrodes for multifunctional supercapacitors

Developing flexible electrode is essential for new generation wearable electronics and energy devices. Combining with membrane-assisted vacuum filtration, highly flexible and stable hybridized electrodes, containing of S-doped graphene, carbon nano-onion (OLC) and Ni3S2 composite (GCNi3S2) are obtained. X-ray absorption characterizations reveal the transfer of electrons from C to Ni atoms due to the tight interface between Ni3S2 and GO/OLC, indicating the synergistic effect on fast redox reaction and ultrashort ion diffusion pathway among the hybrid electrodes. The assembled flexible symmetrical all-solid-state supercapacitor exhibits high volumetric capacitance of 55.3 F cm−3, along with an outstanding energy density of 3.63 Wh cm−3 and excellent stability of 5000 cycles with 97.2% capacitance remaining. The bending tests further confirm outstanding flexible performance in the capacitor device. Moreover, the assembled micro supercapacitor with GCNi3S2 electrode indicates the advantage of this membrane-assisted assembled strategy for easily realizing various flexible films as multitype supercapacitor's electrode which is otherwise difficult for powder-like materials.

Importance of microstructure and interface in designing metal oxide nanocomposites for supercapacitor electrodes

In this work, we demonstrate that designing metal oxide nanocomposite with an optimized nanocarbon to metal oxide ratio is required to realize the best electrochemical performance. Using carbon nano-onion (CNO) and TiO2 composite as a model system, it is evidenced that the formation of interfacial structure and the existence of electrical percolation networks are essential to enhance electrical performance of the composite. When the aforementioned conditions are satisfied, CNO/TiO2 hybrid nanocomposites (CTHNs) with only 11wt% TiO2 loading exhibits excellent electrochemical performance. The maximum specific capacitance obtained for this composite electrode is 386Fg−1 at a scan rate of 5mVs−1, which is the highest reported value till date in a TiO2 composite electrode measured in a two electrode cell configuration. At this composition, excellent electrochemical stability is obtained with only 5% capacitance degradation over 2000cycles. As the TiO2 loading increases the electrochemical performance decreases.

Carbon nano-onions as fluorescent on/off modulated nanoprobes for diagnostics.

Multishell fullerenes, known as carbon nano-onions (CNOs), have emerged as a platform for bioimaging because of their cell-penetration properties and minimal systemic toxicity. Here, we describe the covalent functionalization of CNOs with a π-extended distyryl-substituted boron dipyrromethene (BODIPY) dye with on/off modulated fluorescence emission activated by an acidic environment. The switching properties are linked to the photoinduced electron transfer (PET) characteristics of the dimethylamino functionalities attached to the BODIPY core. The on/off emission of the fluorescent CNOs is fast and reversible both in solution and in vitro, making this nanomaterial suitable as pH-dependent probes for diagnostic applications.

Fundamental Trends in Electrochemical and Physico-Mechanical Properties of Prospective Electrode Materials for Electrical Energy Storage with Plasmon Energy

Plasmons are the major quantized collective longitudinal excitations of valence electrons generated by fast electrons in solids in the low-loss range (0 to 50 eV). The energy of plasmons is related to the valence electron density n as, Ep = ħωp ≅ [(ħωp f ) + Eg 2 ] 1/2 , where ωp f = [ne2 /(ε0m)] 1/2 is the free electron plasma frequency (1016 to 1017 Hz), e is the electron charge, ε0 is the permittivity of vacuum, m is the electron mass and Eg is the bandgap energy (usually Eg 2<<Ep 2 ). Due to ability to probe electronic structures of materials for electrical energy storage (EES) with high spatial and spectral resolution, valence electron energy-loss spectroscopy (VEELS) in a scanning/ transmission electron microscope (S/TEM) enable obtaining copious information on the band structure, intra- and interband transitions, bandgaps, densities of states, phase and chemical compositions, bonding, dielectric and optical response. Since valence electron states are primarily responsible for the charge transfer, capacities, energy densities and many other intrinsic solid-state parameters governing electrochemical performance, plasmons externally induced by electron beams can be employed to probe related physical properties in multiphase EES systems potentially with a sub-nm lateral resolution. The fundamental origins of correlations between elastic constants, cohesive energy and Ep (n) for nanophase electrode materials will be discussed. Materials with preferentially covalent and metallic bonding, which constitute the number of EES systems, obey the universal binding-energy relation (UBER) describing relationships between the cohesive energy Ecoh , the bulk modulus Bm , and the volume plasmon energy Ep :1 Bm = (1/12 p)rws -3 Ecohη 2 = (m/4e2 ħ 2 Nve )Ecohη2 (Ep 2-Eg 2 ). Here rws is the Wigner-Seitz (WS) atomic radius, η is the anharmonicity parameter, Nve is the number of valence electrons per atom and Vwse is the WS volume. The universality and scaling reflect the nature of electron - atom nuclei (ion) interactions and an essentially exponential decay of the electron density with interatomic distance, thus indicating that Ep is an invaluable parameter to characterize physical properties of engineering EES materials. First principle calculations of elastic properties for Li, Si and Li-Si alloys 2 as well as experimental and theoretical analyses of VEEL spectra of Li-Si phases 3 indicate strong correlations between Ep , n, Li content and elastic moduli (Fig. 1a). For monitoring physico-chemical changes during cycling of Si anodes with VEELS/STEM spectroscopic imaging, one can therefore use these correlations to determine and map both elastic properties and compositions of the Li-Si phases. Nanophase carbons (soot particles (fullerenes), nanotubes, graphene, mesoporous carbons) are widely used as a conductive structure-holding matrix for electrodes, current collectors and separators in various types of batteries and supercapacitors. 4 Due to mixed sp2/sp3 bonding and subsequently different short-range and long-range atomic ordering, carbons exhibit a broad variety of physico-mechanical properties regarding hardness and elasticity. Assuming each carbon atom supplies 4 valence electrons to the solid, the mass density, r, is related to n and Ep as ρ = nMC /4NA = ε o m*MCEp 2/4NAħ2e2 = (m*/m) Ep 2 /276.79, where MC is the carbon atomic weight, NA is the Avogadro number, m* is the renormalized electron mass, and the ratio m*/m = 0.87. Several forms of carbons (diamond, graphite, diamond-like, hydrogenated and amorphous films) exhibit strong correlations between the energy of the mixed σ+π volume plasmon peak, Epmax , ρ, amount of sp2/sp3 bonding ratio and Hm. (Fig. 1b). The estimated microhardness of individual 20-60 nm carbon nanoonions, Hm (C65) = 1286 kgmm-2 is typical for carbon soot (800-1760 kgmm-2). 1 The value reported for elemental sulfur, H m(S8 ) = 25-32 kgmm-2, can be assigned to weak intermolecular bonding in the solid as compared to intramolecular covalent bonding within molecular S8 units. 5 The large modulus mismatch and poor cohesion between hard carbons and soft sulfur microparticles may explain the propensity for cracking along sulfur-carbon interfaces, which often occurs upon drying of S 8-carbon cathodes. The variations in H m between the components in poly(S-random-1,3-diisopropenylbenzene) copolymer-carbon cathodes appear to be significantly less, hence the enhanced fracture toughness leads to a crack-free morphology. 4 Utilizing Ep - elastic moduli (Hm ) – composition (density) correlations, one can employ VEELS-S/TEM to determine quantitatively and image physico-mechanical properties of nanophase electrode materials in situ providing further insights into the structure - property relations in prospective EES systems and design of intentionally modified high-performance electrode materials. [1] V.P. Oleshko, J. Nanosci. Nanotechnol. 12 (2012), 8580. [2] V.B. Shenoy, et al., J. Power Sources 195 (2010) 6825. [3] J. Danet, et al., Phys. Chem. Chem. Phys., 12 (2010) 220. [4] V.P. Oleshko, et al., Microsc. Microanal. 22 (2016) 1198. [5] H. Li, Y.H. Han, R.C. Bradt, J. Mater. Sci . 29 (1994) 5641. Figure 1

Hydrogen storage properties of multi-walled carbon nanotubes and carbon nano-onions grown on single and bi-catalysts including Fe, Mo, Co and Ni supported by MgO

The effects of various catalysts including Fe, Mo, Ni, Co and their dual compounds supported by MgO, on production yield, diameter, quality and hydrogen storage properties of carbon nanostructures (CNSs) containing multi-walled carbon nanotubes and carbon nano-onions are studied. It is shown that the production yield of CNSs depends on applied catalyst. The production yields of CNSs are in descending order by using the following catalyst as: Co/Mo, Fe/Mo, Ni/Mo, Mo, Fe/Co, Fe/Ni, Fe, Ni, Co and Ni/Co. Moreover, the CNSs grown on Fe/Co@MgO catalyst have the highest quality, and those grown on Mo@MgO catalyst have the highest surface area, micro-pore distribution and dangling bands, compared to the others. The results of Raman spectroscopy and N2 adsorption confirm the relation between D′ peak area and pores volume less than 10 nm. The hydrogen storage capacities of CNSs grown on the catalysts with production yield more than 45% are in the ascending order as: Mo, Ni/Mo, Fe/Mo, Co/Mo and Fe/Co. It inferred that the CNSs grown on catalysts including Mo are more suitable for hydrogen storage applications, due to high micro-pores (vacancy-like defects) and likely presence of molybdenum carbide structures for enhancing hydrogen uptake. The findings elucidate that specific surface area, micro and meso-pore (certainly less than 10 nm), and vacancy-like defects of the CNSs affect hydrogen uptake and desorption temperature of the stored hydrogen.

Ionic liquid-derived Co3O4/carbon nano-onions composite and its enhanced performance as anode for lithium-ion batteries

In this work, a novel composite of Co3O4 nanoparticle and carbon nano-onions (CNOs) is synthesized by using ionic liquid as carbon and nitrogen source through a facile carbothermic reduction followed by low-temperature oxidation method. The SEM and HRTEM images reveal that the Co3O4 particles are homogenously embedded in the CNOs. Due to the unique nano-structure, the electrolyte contacts well with the active materials, leading to a better transfer of lithium ions. Moreover, the unique nano-structure not only buffers the volume changes but also facilitates the shuttling of electrons during the cycling process. As a result, the electrode made up of Co3O4/CNOs composite delivers favorable cycling performance (676 mAh g−1 after 200 cycles) and rate capability (557 mAh g−1 at the current of 1 C), showing a promising prospect for lithium-ion batteries as anode materials.

Improvement of the Structural and Chemical Properties of Carbon Nano‐onions for Electrocatalysis

AbstractHeteroatom doping of carbon nanostructures is a convenient tool to control their physicochemical properties and to make them suitable for various applications. Carbon nano‐onions (CNOs) doped with nitrogen (N‐CNOs) have been prepared by annealing aminated‐nanodiamond particles (AM‐NDs) at different temperatures (1150, 1450 and 1650 °C) in an inert He atmosphere. Their physicochemical properties were compared with those of pristine CNOs obtained from non‐functionalized NDs under the same experimental conditions. The carbon nanostructures were characterized using transmission (TEM) and scanning (SEM) electron microscopy, X‐ray powder diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, porosimetry, and differential‐thermogravimetric analyses (TGA‐DTG). Their physicochemical properties are systematically discussed for undoped and for the nitrogen‐doped CNO samples. The results reveal that the surface morphology and the structure of undoped and nitrogen‐doped CNOs vary with the annealing temperature. All of these materials were electrochemically tested as electrode materials for enzyme‐free catalysis of hydrogen peroxide. The nitrogen‐doped carbon nanostructures have a higher catalytic activity than undoped nanostructures obtained under the same experimental conditions.

Carbon Nano-Onions as a Functional Dopant to Modify Hole Transporting Layers for Improving Stability and Performance of Planar Perovskite Solar Cells

Poly (3,4-ethylenedioxythiophene) polystyrene sulphonate (PEDOT:PSS) is the most widely used hole transporting layer (HTL) in planar perovskite solar cells, which shows excellent optical, electrical properties and good compatibility with low temperature, solution and flexible processing. Nevertheless, the acidic and hygroscopic property of PEDOT:PSS restricts its film conductivity and leads to the degradation of device stability. Herein, for the first time, we introduce the unprecedentedly zero-dimensional dopant of carbon nano-onions (CNOs) and the functionalized oxidized carbon nano-onions (ox-CNOs) to modify the PEDOT:PSS HTL. Besides the merits of high conductivity and suitable energy level, the CNOs and ox-CNOs modified PEDOT:PSS HTLs could provide a superior perovskite crystalline film with large-scale grains and orderly grain boundaries exhibiting a high surface tension with the hydrophobic property, resulting in a significant enhancement of PCE from 11.07% to 15.26%. Moreover, by suppressing the corrosion effect of PEDOT:PSS on ITO electrode, a dramatic improvement in the device stability has also been obtained.

Curvature-Induced Metal–Support Interaction of an Islands-by-Islands Composite of Platinum Catalyst and Carbon Nano-onion for Durable Oxygen Reduction

Geometry of carbon supports significantly affected electrochemical durability of Pt/C (platinum electrocatalyst supported by carbon) for oxygen reduction reaction (ORR). Carbon nano-onion (CNO) was used as the support, which is characterized by its nanosize (similar to Pt size) and high curvature. Superior ORR durability was guaranteed by Pt/CNO due to (1) its islands-by-islands configuration to isolate each Pt nanoparticle from its neighbors by CNO particles; (2) highly tortuous void structure of the configuration to suppress Ostwald ripening; and (3) the curvature-induced strong interaction between CNO and Pt. The finding that highly curved carbon surface encourages electron donation to catalysts was first reported.

The synthesis of carbon nanostructures from tea plant wastes

ABSTRACTTea wastes are rich in carbon, nitrogen and potassium but poor in phosphorus, which signifies that they can also be used to reduce metal oxides after they are carbonised. The tea wastes were carbonised at the first stage. The sample, which was put into a ladle with screw cap, was carbonised in a muffle furnace at 400, 500, 600, 700 and 800°C for 30, 60, 90, 120, 240, 360, 720 and 1440 min. It was determined that carbon and sulphur contents of the sample carbonised at 800°C for 1440 min were 94.68 and 0.05%, respectively. Calorific value of the same sample was 8652 cal g−1. It was found that with increasing temperature, carbon ratio of the carbonised samples increased and their sulphur ratio decreased from 0.39 to 0.05%. The carbonised structure was subjected to the milling process as the second stage. In the milling process, particle size of the carbon-rich sample was brought into nano size and the structure acquired the energy, required for the third stage. The amorphous carbon structure obtained after the milling process was subjected to annealing process at 1400°C as the third stage. As a result of these processes, carbon nanotubes (CNTs), carbon nano-onion structures and amorphous carbon structures were determined in the structure.