Synthesis Of Carbon Nanoparticles Research Articles

Facile synthesis of carbon nanoparticles from sodium alginate via ultrasonic-assisted nano-precipitation and thermal acid dehydration for ferric ion sensing

Carbon nanoparticles have emerged as a promising alternative to the well-known quantum dots in many biological applications due to their excellent optical properties and biocompatibility. It has received considerable attentions from researchers especially in the aspects of producing these carbon nanomaterials via easier and cheaper synthetic routes. On this motivation, we hereby report an economical and facile synthesis of carbon nanoparticles from alginate via a simple two-step procedure; nano-precipitation through ultrasonication followed by thermal acid carbonisation. Nano-precipitation was first performed on the alginate stock solution to produce nanoparticles with controlled morphology. Precipitation was performed in acidic solution that has coagulated the alginate chains into nanoparticles. Ultrasonic treatment was found crucial to assist the formation of nanoparticles that were more homogenous in the size distribution at around 100nm. The shape was also more spherical as compared to those without ultrasonic treatment. In the carbonisation step, thermal dehydration was employed using concentrated sulphuric acid that has successfully converted the preformed alginate nanoparticles into carbon nanoparticles. The carbon nanoparticles isolated showed high fluorescence even without further surface passivation. The fluorescence of these carbon nanoparticles were utilised for sensitive and selective sensing of ferric ions and it was evaluated to have a linear analytical dynamic range up to 25μM with a limit of detection (LOD) as low as 1.06μM. The system was successfully employed to detect ferric ions in real water sample.

Large-scale solvothermal synthesis of fluorescent carbon nanoparticles

The large-scale production of high-quality carbon nanomaterials is highly desirable for a variety of applications. We demonstrate a novel synthetic route to the production of fluorescent carbon nanoparticles (CNPs) in large quantities via a single-step reaction. The simple heating of a mixture of benzaldehyde, ethanol and graphite oxide (GO) with residual sulfuric acid in an autoclave produced 7 g of CNPs with a quantum yield of 20%. The CNPs can be dispersed in various organic solvents; hence, they are easily incorporated into polymer composites in forms such as nanofibers and thin films. Additionally, we observed that the GO present during the CNP synthesis was reduced. The reduced GO (RGO) was sufficiently conductive (σ ≈ 282 S m−1) such that it could be used as an electrode material in a supercapacitor; in addition, it can provide excellent capacitive behavior and high-rate capability. This work will contribute greatly to the development of efficient synthetic routes to diverse carbon nanomaterials, including CNPs and RGO, that are suitable for a wide range of applications.

Synthesis and characterization of carbon nanoparticles and their modified carbon paste electrode for the determination of dopamine

In this paper, a green and facile approach is presented for the synthesis of carbon nanoparticles (CNPs) by a soot based method using the natural precursor castor oil. The synthesized carbon nanoparticles were used in the detection and electrochemistry of dopamine (DA), ascorbic acid (AA) and uric acid (UA). The synthesized product is characterized by Powdered X-ray diffraction (PXRD), UV–visible absorption spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray spectrum (EDS) and Infrared spectroscopy (IR). CNPs modified carbon paste electrodes provided a detection limit for DA 1.2×10−7M. The cyclic voltammetric response of DA at a carbon nanoparticles modified carbon paste electrode was excellent when compared to a bare carbon paste electrode. The effect of scan rate, concentration, and pH effects on the voltammogram of DA were studied as well as the effects of the surfactants sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100).

Facile hydrothermal synthesis of carbon nanoparticles and possible application as white light phosphors and catalysts for the reduction of nitrophenol

We report a simple hydrothermal synthesis of highly reproducible carbon nanoparticles in a size range between 2 and 7 nm from a single precursor sucrose without either surface passivating agents or acids and bases. The carbon nanoparticles can be used as white light phosphors, especially for ultraviolet light emitting diodes and metal-free catalyst for the reduction of nitrophenol.

Controlled Synthesis of Carbon Nanoparticles in a Supercritical Carbon Disulfide System.

Carbon nanoparticles with large surface areas were produced by the reduction of carbon disulfide with metallic lithium at 500 °C. The carbon nanoparticles account for about 80% of the carbon product. The carbon nanoparticles were characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy and N2 physisorption. The results showed that carbon nanoparticles predominate in the product. The influence of experimental conditions was investigated, which indicated that temperature plays a crucial role in the formation of carbon nanoparticles. The possible formation mechanism of the carbon nanoparticles was discussed. This method provides a simple and efficient route to the synthesis of carbon nanoparticles.

Rapid synthesis of carbon nanoparticles with an optimized combination of specific surface area and crystallinity by a plasma-assisted single-step process

This paper reports controlled synthesis of carbon nanoparticles by an expanded thermal plasma jet assisted technique through a single-step, high-throughput process. The plasma discharge zone in the experimental reactor remained isolated from the particle nucleation/growth chamber through a supersonic nozzle, which allowed using the sample collection chamber pressure as an efficient control parameter to synthesize carbon nanostructures with tailored combination of some important properties. Low chamber pressure conditions produced samples with both good specific surface area and crystallinity, which may be ideal for use as an efficient catalyst support material as well as in batteries and super capacitors. This dominantly mesoporous sample was also found to have good hydrogen absorption properties. Another significant observation was that the average number of carbon nano-sheets stacked together inside the crumpled paper like layers increased with pressure in the sample collection chamber. Optical emission spectroscopic techniques were used to measure the effective cooling rates responsible for the particle nucleation process under different experimental conditions, which also indicated that C2 dimer molecules are the basic precursors behind the formation of these carbon nanostructures.

Synthesis of Small Carbon Nanoparticles in a Microwave Plasma Flow Reactor

Abstract Unusually small carbon nanoparticles were synthesized in a microwave plasma flow-reactor by pyrolysis of 0.3–1.2% CH4, C2H4, and C2H2 with 0.3–3.6% addition of molecular hydrogen in argon. Final particle sizes were analyzed by in-line particle-mass spectrometry (PMS) and by transmission electron microscopy (TEM). TEM measurements of primary particle sizes were found to be in a good agreement with PMS data. The carbon particles formed in the plasma generated by a 2.45 GHz magnetron with an applied power of 180 W and a total pressure of 13 mbar have diameters of 4–6 nm. The type of hydrocarbon precursor and 0.3–3.6% of hydrogen addition did not noticeably influence the final particle sizes. The formation of such small particles is attributed to the low pressure and the comparably low operation power. This method of small carbon nanoparticles synthesis could be useful for the production of carbon black material, where large surface area is important.

Synthesis of Carbon Nanoparticles from Kerosene and their Characterization by SEM⁄EDX, XRD and FTIR

Carbon nanoparticles (CNPs) were synthesized by a simple way of incomplete combustion of kerosene. Synthesized nanoparticles were characterized by Scanning electron microscope (SEM), Energy dispersive x-ray (EDX), Powder x-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). The SEM particle sizes of prepared CNPs were found to be non-uniform. The average size of particles is in the range of 20-100 nm. EDX analysis predicts the presence of pure carbon without any contamination. X-ray powder diffractometric analysis of prepared CNPs indicates the presence of large amounts of amorphous carbon material in association with hexagonal graphite lattice. FTIR spectroscopic analysis shows that the prepared CNPs are a mixture of elemental carbon and a trace amount of hydrocarbons.

Numerical simulation of carbon arc discharge for nanoparticle synthesis

Arc discharge with catalyst-filled carbon anode in helium background was used for the synthesis of carbon nanoparticles. In this paper, we present the results of numerical simulation of carbon arc discharges with arc current varying from 10 A to 100 A in a background gas pressure of 68 kPa. Anode sublimation rate and current voltage characteristics are compared with experiments. Distribution of temperature and species density, which is important for the estimation of the growth of nanoparticles, is obtained. The probable location of nanoparticle growth region is identified based on the temperature range for the formation of catalyst clusters.

Fe-inserted and shell-shaped carbon nanoparticles by cluster-mediated laser pyrolysis

We report here the high-yield continuous synthesis of carbon nanoparticles with and without Fe content by laser pyrolysis technique. The laser beam decomposes (via C2H4 sensitizer) the Fe(CO)5 as Fe clusters which absorb themselves the laser radiation. They trigger the fast carbon particles formation by exothermic dehydrogenation/polymerization of the surrounded C2H2 molecules. This combination between Fe clusters and C2H2 generates nanoparticles with unusual structure. Depending on the gas pressure in the reaction chamber, two kinds of nanoparticles were obtained: at lower pressure, 30–40nm diameter particles with a defective structure, part of them crowded with Fe clusters (3–6nm) and two types of nanoparticles (around 50–60nm) at the highest pressure. Some of them have a shell-shape structure, presenting a distinct envelope, other with a turbostratic arrangement, and few containing one or several smaller (3–20nm) Fe nanoparticles trapped inside. We consider that these particular structures of our nanoparticles may be useful in applications such as MRI applications, drug delivery or catalysts.

Arc plasma synthesis of carbon nanostructures: where is the frontier?

In this perspective paper, we critically analyse the state-of-the-art of arc discharge technique of carbon nanoparticle synthesis. We discuss improving controllability of the arc discharge synthesis of carbon nanotubes, synthesis of graphene as well as general understanding of the synthesis process. Fundamental issues related to relationship between plasma parameters and carbon nanostructure characteristics are considered. Effects of electrical and magnetic fields applied during single-wall carbon nanotube synthesis in arc plasma are explored. Finally our personal opinion on what future trends will be in arc discharge synthesis is offered.

Hg(II) sensing based on functionalized carbon dots obtained by direct laser ablation

The synthesis of carbon nanoparticles obtained by direct laser ablation [UV pulsed laser irradiation (248 nm, KrF)] of carbon targets immersed in water is described. Laser ablation features were optimized to produce carbon nanoparticles with dimensions up to about 100 nm. After functionalization with NH 2–polyethylene-glycol (PEG 200) and N-acetyl- l-cysteine (NAC) the carbon nanoparticles become fluorescent with excitation and emission wavelengths at 340 and 450 nm, respectively. The fluorescence decay time was complex and a three-component decay time model originated a good fit ( χ = 1.09) with the following lifetimes: τ 1 = 0.35 ns; τ 2 = 1.8 ns; and τ 3 = 4.39 ns. The fluorescence of the carbon dots is sensitive to pH with an apparent p K a = 4.2. The carbon dots were characterized by 1H NMR and HSQC and the results show an interaction between PEG 200 and the carbon surface as well as a dependence of the chemical shift with the reaction time. The fluorescence intensity of the nanoparticles is quenched by the presence of Hg(II) and Cu(II) ions with a Stern–Volmer constant (pH = 6.8) of 1.3 × 10 5 and 5.6 × 10 4 M −1, respectively. As such the synthesis and application of a novel biocompatible nanosensor for measuring Hg(II) is presented.

Naphthalene as an alternative carbon source for pyrolytic synthesis of carbon nanostructures

The utilization of naphthalene as an alternative carbon source for synthesis of carbon nanoparticles by pyrolyzing with ferrocene in a quartz tube reactor was experimentally investigated. Carbon nanoparticles including carbon nanotubes (CNTs) and carbon nanocapsules (CNCs), which contained Fe particles in their carbon shells, were simultaneously fabricated. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses revealed that morphology and size of the carbon nanostructure strongly depended on the pyrolysis temperature. At a higher temperature, formation of CNCs would become more enhanced. Particle size distribution and yield of the synthesized products were also significantly influenced by the pyrolysis temperature.

Indene Formation from Alkylated Aromatics: Kinetics and Products of the Fulvenallene + Acetylene Reaction

A novel reaction is described for formation of the polyaromatic hydrocarbon (PAH) indene in aromatic flames, via the reaction of fulvenallene with acetylene (C2H2). Fulvenallene has been recently identified as the major decomposition product of the benzyl radical, the dominant intermediate in the oxidation of alkylated aromatic hydrocarbons, yet it is not presently included in kinetic models for aromatic oxidation or PAH/soot formation. Ab initio calculations with the G3B3 theoretical method show that acetylene adds to fulvenallene with a barrier of around 27 kcal mol(-1). This forms an activated C9H8 adduct that can rearrange to indene and dissociate to 1-indenyl + H with energy barriers below that of the entrance channel. Master equation simulations across a range of temperature and pressure conditions demonstrate that for temperatures relevant to combustion indene is the dominant product at high pressures while 1-indenyl + H dominate at lower pressures. At low to moderate temperatures, the production of collision stabilized cyclopentadiene-fulvene intermediates is also significant. The results presented in this study provide a new pathway to cyclopenta-fused PAHs in aromatic combustion and are expected to improve modeling of PAH and soot formation. The formation of cyclopenta-fused C5-C6 structures is required to describe the flame synthesis of carbon nanoparticles like fullerenes and buckybowls (corannulene). Improved rate expressions are also reported for the 1-indenyl + H --> indene association reaction, and for the reverse dissociation, from variational transition state theory calculations. The new rate constants are significantly different than current estimates, primarily due to a re-evaluation of the indene C-H bond dissociation energy.

A non-thermal plasma process for the gas phase synthesis of carbon nanoparticles

Plasma processes, mostly involving so-called “thermal” plasmas, have been exploited in many instances for the gas phase synthesis of carbon nanoparticles such as carbon black, fullerenes or carbon nanotubes. A non-thermal plasma process, based on low current–high voltage discharges, has been developed for the gas phase synthesis of carbon nanoparticles at atmospheric pressure. This process can produce a broad range of products such as furnace-type carbon blacks, acetylene-type carbon blacks, and nanoparticles with a peculiar morphology that we call “crumpled paper sheets”. The products were characterized by scanning and transmission electron microscopy, X-ray diffraction and BET measurements. Some correlations between the operating conditions and the characteristics of carbon nanostructures highlight temperature as a key parameter for controlling the growth, formation, and type of the nanoparticles obtained.

Enhancing effect of monoolein surfactant on carbon nanoparticle synthesis by arc discharge in liquid

Effect of monoolein surfactant which promotes n-hexane to dissolve in water was investigated to enhance the carbon nanoparticle (CNP) synthesis by arc discharge in liquid. The production rate of CNPs consisting of multi-shelled fullerenes and multi-walled carbon nanotubes was increased by the addition of the n-hexane to water with support of monoolein surfactant. An optimal amount of monoolein led to the maximal production rate of CNPs which was ca. two-fold higher than that obtained from a pure water system. This effect is ascribed to the role of n-hexane and monoolein to provide carbon clusters to the arc reactive zone. The hydrodynamic particle sizes of CNPs and their crystallinity were also enhanced by the addition of these organic compounds. As the vapor pressure of the organic component is significantly suppressed, the proposed method is much safer than that using pure organic liquid.

Low-temperature solution synthesis of carbon nanoparticles, onions and nanoropes by the assembly of aromatic molecules

Graphitic carbon nanostructures were prepared in solution by two methods: solvothermal synthesis and hot injection. Small carbon nanoparticles with uniform diameters of 3–6 nm, carbon onion particles with larger diameters of 30–80 nm, and carbon nanoropes with a length of hundreds of nm and a width of 3–20 nm, were formed using commercial mesophase pitches as a carbon precursor through solution-phase synthesis below 200 °C. In the solvothermal synthesis, organic–organic assemblies of aromatic molecules from the pitches could be constrained into different stacking arrangements directed by varying the concentration of the block copolymer P123 template in toluene solution at 200 °C. In the hot injection method, when oleic acid was used as a solvent at 180 °C, the assemblies of the aromatic building blocks were controlled by varying the reaction time (5–30 min) or the concentration of H 2SO 4 catalyst (0.015–0.061 mol L −1) in the nucleation and growth process.

Low‐Pressure PECVD of Nanoparticles in Carbon Thin Films from Ar/H2/C2H2 Plasmas: Synthesis of Films and Analysis of the Electron Energy Distribution Function

AbstractA study of the synthesis of carbon nanoparticles embedded in carbon thin films deposited by radiofrequency (RF) (13.56 MHz) Ar/H2 (4 %)/C2H2 plasmas is presented. The carbon nanospheres exhibit an amorphous structure that is clearly observed at 300 W, under 0.1 Torr, and grows in size with increasing C2H2 between 1 % and 20 %. Above a C2H2 concentration threshold (20 % in this case) carbon nanoparticles are no longer formed. In order to study possible changes in the plasma kinetics, optical emission spectroscopy (OES) is used to evaluate the electron temperature while changing the C2H2 concentration. In addition, an analysis of the temporal evolution of the electron energy distribution function (EEDF) is carried out for various C2H2 concentrations considering the effects produced by electron‐vibrational superelastic collisions and relative concentration of excited Ar atoms. Finally, the morphological and tribological features of the deposited films are characterized.

Solid - Phase Synthesis of Carbon Nanoparticles and their Application to Direct Methanol Fuel Cell

Carbon nanoparticles were prepared by simple method. TEM image shows that the particle size is several nanometers. Furthermore, the specific surface area of the material is reached for 425.8 m2/g. It is much larger than that of carbonVulcan-XC72, which they is widely used as catalyst supports for DMFC electrodes. Carbon nanoparticles is a kind of promising material used for catalyst support in DMFC.

Plasma pyrolytic synthesis of carbon nanostructures in a mixture of nitrogen and propane-butane

The results of experimental investigation of the parameters of gaseous-phase synthesis of carbon nanoparticles in atmospheric-pressure arc reactors operating with mixtures of nitrogen and hydrocarbon gases have been given. It has been revealed that, under the conditions studied, arc plasma synthesis makes it possible to synthesize highly dispersed carbon products with a content of fullerene phases of up to 15 wt.% and nanotubes to 3–5 wt.%.