Onion-like Carbon Nanoparticles Research Articles

The Fluid Interface Reactions, Structures and Transport (FIRST) Energy Frontier Research Center

The overarching goal of the FIRST Center, which is in its sixth year of operation, is to develop fundamental understanding and validated, predictive models of the unique nanoscale environment at fluid-solid interfaces, that will enable transformative advances in electrical energy storage and electrocatalysis. The Center is primarily based at Oak Ridge National Laboratory, and includes research at Argonne National Lab, Drexel, Penn State, Vanderbilt, and the Universities of California at Davis and Riverside, Delaware and Minnesota. In order to achieve our goal, we integrate novel substrate and electrolyte synthesis and characterization, advanced electron (TEM) and scanning probe microscopies (SPM), neutron and X-ray scattering, and multiscale computational modeling ranging from quantum Monte Carlo to classical density functional theory approaches. Electrolytes investigated include aqueous, polar organic and room temperature ionic liquids (RTILs), representing increasing cost and electrochemical stability, and decreasing viscosity, competing factors in device performance, where charge/discharge rates are affected by viscosity, while stored energy in electrochemical capacitors increases with the square of the applied potential. Organic solvents have the added problem of high volatility and flammability. We investigate the interactions of these fluids with a wide range of carbon materials and recently an entirely new class of 2D transition metal carbonitrides, known as MXenes. Like graphenic materials, MXenes can be conductive, but they can also be strongly hydrophyllic and well-suited for multivalent ion adsorption and intercalation. Our recent efforts have focused on predicting the functionality of interfacial systems for capacitive and pseudocapacitive electrical energy storage in microdevice to grid scale applications. The structures, dynamics and transport properties of RTILS at planar, curved and enclosed (nanopore) surfaces is intensely investigated, and we have begun investigating the role of imidazolium RTIL cations in co-catalyzing the highly efficient and selective electrocatalytic conversion of CO2 to CO at negatively charged, post-transition-metal electrode surfaces as a first step in Fischer-Tropsch-type processes for converting CO2 to liquid fuels and chemical feedstocks. Unique contributions of the FIRST Center include the development of 1.) Electrochemical Strain Microscopy, an SPM method that probes the expansion and contraction of both battery and nanoporous electrochemical capacitor electrodes during charging/discharging with nanometer spatial resolution; 2.) in situ, operando electrochemical flow cells S/TEM studies of ion transport and interfacial reactivity with subnanometer resolution; 3.) unique applications of neutron scattering to probe the structures and transport properties of fluids within hierarchical pore systems; 4.) onion-like carbon nanoparticles with sphereical external surfaces and graphite-like conductivity and inertness; 5.) defect-driven and selective transport of protons across large, pristine single-layer graphene sheets via a Grotthus mechanism; 6.) Electrochemical Flow Capacitor systems for grid scale applications; 7) coarse-grained models like classical density functional theory and reactive classical MD force fields to achieve fundamental and predictive understanding of interfacial system functionality at larger time and length scales; and 8.) efficient lower temperature and/or less toxic synthesis routes for a wide array of ultrahigh surface area carbon and MXene materials.

Properties of carbon nanomaterials produced from gaseous raw materials using high-frequency electrodischarge processing

The properties of carbon nanomaterials, produced with the help of the method for the high-frequency electrodischarge processing of hydrocarbon gases, based on the creation of non-equilibrium plasma under variation of frequency and treated gas, have been studied. It is shown that the synthesis of onion-like structures and globular carbon nanoparticles with turbostratic structure is possible, depending on the type of gas.

Gram scale synthesis of green fluorescent water-soluble onion-like carbon nanoparticles from camphor and polystyrene foam

Herein, we report a cost effective and simple method for gram scale synthesis of water-soluble onion-like carbon nanoparticles (wsOCNPs) using common carbonaceous sources like camphor and polystyrene foam. The synthetic methodology involves ambient burning of these carbon rich materials under an insufficient oxygenic atmosphere. Furthermore, the oxidative treatment of carbon soot (CS) imposes dense carboxylic group functionalization over the surface of wsOCNPs. The high degree of surface functionalization imposes a self-passivated fluorescence effect along with photostability, which makes the material a potential candidate for bio-imaging purposes. Surprisingly, these wsOCNPs show exceptional excitation wavelength independent fluorescence emission properties over a wide region of the visible spectrum.

Features of the transformation of detonation nanodiamonds into onion-like carbon nanoparticles

On the basis of the results of investigations carried out by differential scanning calorimetry, X-ray diffraction, nuclear magnetic resonance, high-resolution transmission electron microscopy, and Raman spectroscopy, a scheme for the transformation of detonation nanodiamonds (which are agglomerates of smaller particles) into onion-like carbon nanoparticles during vacuum annealing is verified. At high temperatures, the transition of an individual nanodiamond occurs in a short period of time and may proceed via an amorphous state.

In situ formation of onion-like carbon from the evaporation of ultra-dispersed nanodiamonds

We report the in situ formation of onion-like carbon (OLC) by evaporation from a nanodiamond source under ultra-high vacuum conditions. The OLC is characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) and is found to be highly defective but completely separated. The absence of any signature in XPS, Raman spectra and TEM associated with nanodiamond in the film suggests that the OLC is formed from carbon vapor or by the direct evaporation of only the smallest particles resulting from nanodiamond graphitization. The method thus provides a route to the formation of individually separated OLC nanoparticles.

The production of onion-like carbon nanoparticles by heating carbon in a liquid alcohol

A simple method to fabricate carbon nanoparticles (CNPs) by passing an electric current through a carbon filament (CF) in liquid alcohol is reported. A large amount of gas bubbles (containing CO, H2, CO2, methane, ethane, acetylene and ethene) have been generated in the reaction between carbon and ethanol alcohol at a high temperature of about 2600 K. Scanning and transmission electron microscopy (TEM) images confirm the presence of carbon onion-like particles with diameters of about 20–50 nm. TEM images show that the spherical, disordered carbon onion-like particles seem to be in the majority. The carbon nanotubes are not formed under these conditions, which indicates that the nanoparticles are produced by thermal pyrolysis of alcohol vapors in the gas bubbles. Importantly, this carbonaceous production suggests that the carbon source in this method is mainly alcohol.

Onion-like carbon nanoparticles generated by multiple laser irradiations on laser-ablated particles

A one-step process to synthesize onion-like carbon nanoparticles at room temperature under atmospheric pressure was developed. Periodic pulsed laser irradiation of carbon nanoparticles confined in the cavity of a carbon target rod induces drastic changes to their structure, changing them from amorphous to ordered concentric graphitic shells. The size distribution of gas-borne nanoparticles measured by a scanning mobility particle sizer showed the mean mobility diameter decreased from 83 nm to 18 nm as a result of restructuring of carbon agglomerates. Polyhedral and unagglomerated nanoparticles with shell structures composed of multiple graphene sheets were observed by a transmission electron microscopy.

Catalytic Graphitization of Phenolic Resin

The catalytic graphitization of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate (FN) was studied in detail. The morphologies and structural features of the products including onion-like carbon nanoparticles and bamboo-shaped carbon nanotubes were investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction and Raman spectroscopy measurements. It was found that with the changes of loading content of FN and residence time at 1000°C, the products exhibited various morphologies. The TEM images showed that bamboo-shaped carbon nanotube consisted of tens of bamboo sticks and onion-like carbon nanoparticle was made up of quasi-spherically concentrically closed carbon nanocages.

Synthesis of carbon-encapsulated iron carbide/iron nanoparticles from phenolic-formaldehyde resin and ferric nitrate

Carbon-encapsulated iron carbide/iron nanoparticles have been synthesized on a large scale by the heat treatment of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate. The effects of heating temperature on the morphologies and structures of carbonized products were investigated using transmission electron microscope, high-resolution transmission electron microscope and X-ray diffraction measurements. The products with diameter distribution of 20–100 nm consisted mainly of spheroidal nanoparticles separated by hollow onion-like carbon nanoparticles.

Catalyst-free synthesis of onion-like carbon nanoparticles

Catalyst-free synthesis of onion-like carbon nanoparticles

Catalyst-free synthesis of onion-like carbon nanoparticles

A one-step process for the synthesis of onion-like carbon nanoparticles is described. The process is based on a thermolysis of a NaN 3-C 6Cl 6 mixture. The effect of buffer gas (Ar or air) on the yield, morphology, and structure of the carbon products was investigated by electron microscopy, X-ray diffraction, and Raman spectroscopy. The products contained carbon-onions, amorphous carbon nanoparticles, and NaCl. The byproducts were completely removed using a simple purification process. The formation of onion-like nanoparticles is likely caused by a shock wave, a rapid increase of pressure, during thermolysis, which induced the coalescence of phenyl radicals.

A sensible route to covalent functionalization of carbon nanoparticles with aromatic compounds

We report the functionalization of onion-like carbon (OLC) nanoparticles with anthracene by direct covalent binding. The new chemical route is based on the bromine/lithium exchange, commonly used for aliphatic compounds, but applied here to aromatic carbon. Our results provide a new procedure for the chemical functionalization of the OLC nanoparticles, which could be also a new route to functionalization of other species in the carbon nanoparticle family. X-ray photoelectron spectroscopy and infrared spectroscopy were used to monitor the functionalization. The data obtained account for the nature of the ligands at the surface of the OLC and also for the degree of functionalization. We discuss the differences observed between the shifts in the vibrational bands of the anthracene chemisorbed and physisorbed by the OLC. Polycyclic aromatic hydrocarbons (PAHs) and carbon nanoparticles are produced simultaneously in certain regions of space, but also in our atmospheric environment due to the incomplete combustion of hydrocarbons; therefore the spectroscopic changes in the vibrational spectrum of PAHs upon adsorption by carbon nanoparticles can be worthy of multidisciplinary attention. The new functionalization route provides a tool for the manipulation of a highly promising type of carbon nanoparticles with potential applications in nanoelectronics and nanomedicine.

Photoinduced transparency of a suspension of onion-like carbon nanoparticles

We have observed the phenomenon of photoinduced transparency in a suspension of onion-like carbon (OLC) nanoparticles in N,N-dimethylformamide (DMF) under the action of high-power laser radiation (λ = 1064 nm). The OLC particles were prepared from detonation nanodiamonds (NDs) by means of high-temperature annealing in vacuum and then ultrasonically dispersed in DMF. Upon exposure to laser radiation, the optical density of the suspension significantly decreases in the visible and near-infrared range, but increases in the range of wavelengths below 400 nm.

Potential of 129Xe NMR spectroscopy of adsorbed xenon for testing the chemical state of the surface of mesoporous carbon materials illustrated by the example of aggregates of diamond and onion-like carbon nanoparticles

The chemical shift in the 129Xe NMR spectrum of adsorbed xenon is very sensitive to the presence of oxygen-containing functional groups on the surface of mesoporous carbon materials. Well-characterized, structurally similar nanodiamond and onion-like carbon samples are considered here as model objects.

Spectral Properties of Gas‐phase Condensed Fullerene‐like Carbon Nanoparticles from Far‐ultraviolet to Infrared Wavelengths

Carbon solids are ubiquitous material in the interstellar space. However, the formation pathway of carbonaceous matter in astrophysical environments as well as in terrestrial gas-phase condensation reactions is not yet understood. Laser ablation of graphite in different quenching gas atmospheres such as pure He, He/H$_2$, and He/H$_2$O at varying pressures is used to synthesize very small, fullerene-like carbon nanoparticles. The particles are characterized by very small diameters between 1 and 4 nm and a disturbed onion-like structure. The soot particles extracted from the condensation zone obviously represent a very early stage of particle condensation. The spectral properties have been measured from the far-ultraviolet (FUV) ($\lambda$=120 nm) to the mid-infrared (MIR) ($\lambda$=15 ~$\mu$m). The seed-like soot particles show strong absorption bands in the 3.4 ~$\mu$m range. The profile and the intensity pattern of the 3.4 ~$\mu$m band of the diffuse interstellar medium can be well reproduced by the measured 3.4 ~$\mu$m profile of the condensed particles, however, all the carbon which is left to form solids is needed to fit the intensity of the interstellar bands. In contrast to the assumption that onion-like soot particles could be the carrier of the interstellar ultraviolet (UV) bump, our very small onion-like carbon nanoparticles do not show distinct UV bands due to ($\pi-\pi$*) transitions.

The transformation of acetylene black into onion-like hollow carbon nanoparticles at 1000 °C using an iron catalyst

Acetylene carbon blacks were heat treated at 1000 °C in the presence of ferric nitrate. The morphologies and structural features of original carbon blacks and the carbonized product were investigated using TEM, HRTEM, XRD and nitrogen sorption measurements. It was found that, with the increase of ferric nitrate loading from 4:1, 8:1, 12:1 to 16:1 (the weight ratio of ferric nitrate to acetylene carbon black), the yield of carbonized product decreased from 64.6%, 61.8%, 46.2% to 28.6%. Onion-like hollow carbon nanoparticles with diameter of 40 to 100 nm were generated, implying that the discontinuous short fragments of carbon black were reconstructed and transformed into turbostratic concentric graphitic layers by the iron-based catalytic graphitization. The mechanism was discussed briefly.

Large-scale synthesis of onion-like carbon nanoparticles by carbonization of phenolic resin

Onion-like carbon nanoparticles have been synthesized on a large scale by carbonization of phenolic-formaldehyde resin at 1000 °C with the aid of ferric nitrate (FN). The effects of FN loading content on the yield, morphology and structure of carbonized products were investigated using transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction. It was found that the onion-like carbon nanoparticles, which had a narrow size distribution ranging from 30 to 50 nm, were composed mainly of quasi-spherically concentric shells of well-aligned graphene layers with interlayer spacing of 0.336 nm. Based on the results of the investigation, the formation mechanism of onion-like carbon nanoparticles was also discussed.

Individual Multiwall Carbon Nanotubes Spectroscopy by Scanning Transmission X-ray Microscopy

Scanning transmission X-ray microscopy (STXM) has been used to probe the electronic structure of individual multiwall carbon nanotubes by chemical mapping at the nanoscale. Carbon 1s near-edge X-ray absorption fine structure (NEXAFS) spectra of individual structures are shown to be able to differentiate carbon nanotubes from onionlike carbon nanoparticles and to differentiate nanotubes synthesized by different growth methods. Imaging of the very same region by both STXM and transmission electron microscopy is shown to be a very useful and complementary approach.

Analysis of the mechanism of the critical transition in irradiated acetylene that leads to generation of shell-shaped carbon nanoparticles

We have recently reported that onion-like shell-shaped carbon nanoparticles of high crystallinity could be generated through critical transition in the acetylene flow irradiated by a cw infrared CO 2 laser [Choi et al. Advanced Materials 2004;16:1721–25]. This transition appeared as the temperature jump above a threshold value of the laser irradiance. The present paper explains the origin of this recent discovery. The heat balance on the surface of the growing particle is shown to allow the existence of two stable particle temperatures. Then, the temperature jump observed in our recent study is a transition from the low temperature regime to the high temperature regime. Implications of the finding for the processes of the carbon nanoparticle formation from hydrocarbons are also discussed.

Change of surface morphology and field emission property of carbon nanotube films treated using a hydrogen plasma

Large-scaled homogeneous multi-wall carbon nanotube (MWNT) films have been obtained at room temperature by a transfer technique. The surface morphology and microstructure features of the films before and after hydrogen plasma (HP) treatment were investigated by scanning electron microscopy, high-resolution transmission electron microscopy, and micro-Raman spectra. The electrical resistance in the temperature range 5–296 K and field emission in diode structure for the MWNT films were examined. Electron microscopy results demonstrated that the surface of treated nanotubes had become open palpus-like graphite layers or were covered by the onion-like carbon nanoparticles. The temperature dependence on electric resistance for MWNT films, which was fitted by three-dimensional variable range hopping conduction, was observed; and the slope and scope of the temperature dependence for the treated film were larger than that of the untreated one. The field emission tests indicated that the turn-on field (at 0.1 μA/cm 2) decreases from 3.9 to 1.5 V/μm after the sample is treated with hydrogen plasma for 30 min. High emission spot density of about 1.5×10 4 cm −2 is achieved at an applied electric field 5.2 V/μm. The conversion mechanism of the treated carbon nanotubes(CNTs) microstructure and the reason for the change of electronic properties and field emission of MWNT films were discussed.