Onion-like Carbon Nanoparticles Research Articles

Molten Salt Preparation of Carbon Nanostructures for Metal-Ion Storage Applications

Efficient electrical energy storage relies on the preparation of low-cost yet high-quality carbon nanostructures. This presentation introduces innovative molten salt approaches for generating such carbon materials, leveraging diverse carbon sources such as natural or synthetic graphite, biomass waste, and plastic materials. Electrochemical exfoliation of various graphite materials in molten salt is demonstrated to yield electrolytic carbon nanostructures, including graphene nanosheets, carbon nanotubes, and onion-like carbon nanoparticles. The distinctive morphology, structure, and electrical conductivity of these carbon materials are investigated, and their impact on Na-ion and Li-ion storage performances is thoroughly discussed. Furthermore, the presentation explores the molten salt-assisted carbonization of corn lignocellulosic waste, resulting in carbon materials with tailored morphological and compositional characteristics conducive to efficient Li-ion and Na-ion storage performance. Additionally, insights are provided into the transformation of waste plastic materials into graphene-based nanostructures through molten salt techniques, with a focus on their electrical and electrochemical performances. This comprehensive exploration not only underscores the versatility of molten salt methodologies in synthesizing diverse carbon nanostructures but also sheds light on their potential applications in advancing energy storage technologies. References A.R. Kamali*, H. Zhao, J. Alloy. Compd. 949 (2023) 169819H. Zhao, A. Rezaei, A.R. Kamali*, J. Electrochem. Soc. 169 (2022) 054512R. Li, A.R. Kamali*, Chem. Eng. Sci. 265 (2023) 118222A.R. Kamali*, S. Li, Appl. Energy 334 (2023) 120692A.R. Kamali*, J. Yang, Polym. Degrad. Stab. 177 (2020) 109184A. Rezaei, B. Kamali, A.R. Kamali*, Measurement 150 (2020) 107087A.R. Kamali* et al., J. Mater. Chem. A 5 (2017) 19126-19135A.R. Kamali*, Carbon 123 (2017) 205-215

Fabrication of Garlic Oil-Functionalized Onion-Like Carbon Nanoparticles as Effective Nanoadditives for Improved Lubricating Performance

Fabrication of Garlic Oil-Functionalized Onion-Like Carbon Nanoparticles as Effective Nanoadditives for Improved Lubricating Performance

Dynamic tracking of onion-like carbon nanoparticles in cancer cells using limited-angle holographic tomography with self-supervised learning

This research presents a novel approach for the dynamic monitoring of onion-like carbon nanoparticles inside colorectal cancer cells. Onion-like carbon nanoparticles are widely used in photothermal cancer therapy, and precise 3D tracking of their distribution is crucial. We proposed a limited-angle digital holographic tomography technique with unsupervised learning to achieve rapid and accurate monitoring. A key innovation is our internal learning neural network. This network addresses the information limitations of limited-angle measurements by directly mapping coordinates to measured data and reconstructing phase information at unmeasured angles without external training data. We validated the network using standard SiO2 microspheres. Subsequently, we reconstructed the 3D refractive index of onion-like carbon nanoparticles within cancer cells at various time points. Morphological parameters of the nanoparticles were quantitatively analyzed to understand their temporal evolution, offering initial insights into the underlying mechanisms. This methodology provides a new perspective for efficiently tracking nanoparticles within cancer cells.

Wear pressure induced structural changes of OLC nanoparticles and their regulated lubrication performances by mixing with NDs and GO

Here we report the tribological properties of nanosized onion-like carbon (OLC), OLC-nanodiamond (ND), and OLC-graphene oxide (GO) as additives in lubricant oil tested under different wear pressure. Under the wear pressure of 588 N of the four-ball testing, the 0.125 wt% addition OLC reduced the wear volume and the wear scar diameter by 36.29 % and 82.42 %. TEM characterization revealed structural changes in contour of the OLC particles after the wear testing. Pressure-induced agglomeration was seen for the OLC nanospheres, and the squeezed lattice changes resulted in formation of sp3 diamond structure inside the spheres. These structural changes are directly related to the loading force. However, addition of the sp3 NDs and sp2 GO deteriorated the lubricating performances of the OLC-added lubricant oil.

Open-source electrochemical cell for in situ X-ray absorption spectroscopy in transmission and fluorescence modes.

X-ray spectroscopy is a valuable technique for the study of many materials systems. Characterizing reactions in situ and operando can reveal complex reaction kinetics, which is crucial to understanding active site composition and reaction mechanisms. In this project, the design, fabrication and testing of an open-source and easy-to-fabricate electrochemical cell for in situ electrochemistry compatible with X-ray absorption spectroscopy in both transmission and fluorescence modes are accomplished via windows with large opening angles on both the upstream and downstream sides of the cell. Using a hobbyist computer numerical control machine and free 3D CAD software, anyone can make a reliable electrochemical cell using this design. Onion-like carbon nanoparticles, with a 1:3 iron-to-cobalt ratio, were drop-coated onto carbon paper for testing in situ X-ray absorption spectroscopy. Cyclic voltammetry of the carbon paper showed the expected behavior, with no increased ohmic drop, even in sandwiched cells. Chronoamperometry was used to apply 0.4 V versus reversible hydrogen electrode, with and without 15 min of oxygen purging to ensure that the electrochemical cell does not provide any artefacts due to gas purging. The XANES and EXAFS spectra showed no differences with and without oxygen, as expected at 0.4 V, without any artefacts due to gas purging. The development of this open-source electrochemical cell design allows for improved collection of in situ X-ray absorption spectroscopy data and enables researchers to perform both transmission and fluorescence simultaneously. It additionally addresses key practical considerations including gas purging, reduced ionic resistance and leak prevention.

Onion-like carbon nanoparticles as additives in lubricant oil deform inelastically during the wear testing for improved lubrication performances

Nano-carbon has been extensively investigated as an additive to lubricant oil for improved performance. It is still far from a final verdict as to how the physicochemical features of the carbon nanomaterials affect their lubrication efficacy. Here we report the use of onion-like carbon (OLC) particles with the size of 5–10 nm as additives to lubricant oil, and their role in regulating the lubrication is elucidated through characterizing the wear-induced changes to their physiochemistry. Multiple loads are chosen for the wear testing using the four-ball friction tester. Stable dispersion of the OLC particles in lubricant oil was attained by pre-coating the particles with oleic acid molecules. Results showed that the oil with the treated OLC particles of 0.125 wt% reduced the wear scar by 30 % in diameter and the wear volume by 77 %. It was surprisingly noted that incorporation of the OLC nanoparticles particularly alleviated the heavy loading wear by remarkably reducing the friction coefficient. Raman spectroscopy characterization suggested intact chemistry of the particles after the wear testing. However, curvature changes of the particles were seen as revealed by high resolution transmission electron microscopy after the wear testing, indicating inelastic deformation of the particles triggered by the wear-squeezing.

Fabrication of Zwitterionic Polymer-Functionalized Onion-like Carbon Nanoparticles as Aqueous Lubricant Additives.

Onion-like carbon (OLC) is a kind of carbon material with a graphene-like structure and large interlayer spacing, favorable to a good lubricating performance. Herein, a facile method is presented for the preparation of functionalized OLC nanoparticles from candle soot with surface modification. The OLC nanoparticles are collected from combustion soot with candle burning via a simple heat treatment, and then the zwitterionic polymer (polyethylenimine-quaternized derivative, PEIS) can self-assemble onto the OLC surface with epigallocatechin gallate via Michael addition and Schiff-base reaction, thus obtaining PEIS-functionalized OLC nanoparticles (PEIS@OLC). The grafting zwitterionic polymer PEIS endows the OLC nanoparticles with good hydrophilic performance, so the as-obtained PEIS@OLC exhibits outstanding dispersion and lubricating property as a water-based lubricant additive. Compared to pure water, the average coefficient of friction decreases to 0.110 from 0.512, and the corresponding wear volume is reduced by 61.02% with 1.5 wt % addition. The improved lubricating property is mainly due to the synergetic effect of the protective film induced by the tribochemical reaction and the hydration film of zwitterionic polymer PEIS. Besides, the OLC nanoparticles could also display the nanoscale rolling and repairing effects at the friction contact interface, resulting in reduction of friction and wear.

Visible-light promoted hydrogen production by diesel soot derived onion like carbon nanoparticles

Visible-light-driven photocatalytic water splitting has always been considered a promising approach to hydrogen generation. The onion-like carbon nano particles (OCNPs) isolated from diesel engine exhaust soot have shown their strong capability towards the visible-light promoted hydrogen evolution via water splitting. Under visible light irradiation, the hydrogen evolution rate of OCNPs is ∼1075 μM h−1 g−1 which is quite comparable with the available literature without using any dopant materials or co-catalyst. The evolution of hydrogen using the OCNPs is due to the presence of numerous optically active centers and a high sp3/sp2 interface on the surface of OCNPs, which promoted the process of visible-light assisted photocatalytic water splitting. These waste derived OCNPs can serve as high-performance photocatalytic materials for the visible light-to-hydrogen production and could contribute towards the goal to achieve clean energy.

Electrochemical conversion of natural graphite minerals into carbon nanostructures incorporated with Fe3Si for Li-ion storage application

Natural graphite mineral (NGM) is an abundant and low-cost carbon source with the potential of being employed as the precursor for producing high-quality carbon nanostructures for energy storage applications. In this article, one-pot electrochemical conversion of NGM into graphitic carbon nanostructures incorporated with Fe3Si nanocrystals with enhanced bulk electrical conductivity and Li-ion storage performance is reported. To this end, electrodes made of NGM are negatively polarized in molten LiCl-NaCl at 740 °C under various cathode current densities. At 1 A cm−2, the high-yield conversion of the mineral into carbon nanotubes (CNTs), nanofibers and onion-like carbon nanoparticles is realized. The product exhibits a specific electrical conductivity of 9.83 S m2 g−1, and the Li+ transfer resistance of 24 Ω. The Li-ion storage capacity of the material is evaluated to be high at 382 mAh g−1 after 220 Li-ion insertion and extraction cycles under the current density of 200 mA g−1, making the material an attractive low-cost candidate for the anode of lithium ion batteries. The ferromagnetic behavior of the nanostructured Fe3Si incorporated carbon is characterized by the saturation magnetization of 11.1 emu g−1, potentially promoting the recyclability of spent anode material. This article reports on the green and low-cost conversion of NGMs into nanostructured carbon materials with enhanced Li-ion storage performance.

Poly(tannic acid)-functionalized onion-like carbon nanoparticles derived from candle soot serving as potent lubricant additives

Spheroidal onion-like carbon (OLC) nanoparticles exhibit heliocentric graphitic layers are known to possess excellent lubricating properties. Herein, tannic acid (TA) was assembled in-situ onto the onion-like carbon material with Tris (2-aminoethyl) amine (TAEA) to form poly(tannic acid)-functionalized onion-like carbon nanoparticles (P(TA-TAEA)@OLC) via Schiff-base reaction and/or Michael addition. Subsequently, the commercial lubricating additive dialkyl dithiophosphate (DDP) was introduced via Michael addition to bond with the poly(tannic acid) of P(TA-TAEA)@OLC nanoparticles in Tris aqueous solution, to obtain DDP-functionalized onion-like carbon (DDP@OLC) nanoparticles. The as-obtained DDP@OLC nanospheres in the role of lubricating additives demonstrated remarkable friction reduction and wear resistance. With addition of 1 wt % DDP@OLC nanoparticles, the coefficient of friction reduced from 0.17 to 0.10, while the corresponding wear volume loss decreased by 96 %, and the loading capacity reached 600 N from 100 N. The outstanding tribological performance of these as-obtained nanoparticles can be attributable to the formation of a graphitic layer exfoliated from OLC nanoparticles under a high load, and the protective film derived from tribochemical reactions via N, P and S elements of DDP@OLC. Meanwhile, the DDP@OLC nanoparticles can also act as spacers and ball bearings between sliding surfaces, facilitating the enhancement of anti-wear and friction reduction properties.

Onion-Like Carbon Nanoparticles as Additives in Lubricant Oil Deform Inelastically During the Wear Testing for Improved Lubrication Performances

Onion-Like Carbon Nanoparticles as Additives in Lubricant Oil Deform Inelastically During the Wear Testing for Improved Lubrication Performances

Onion-like Carbon (OLC), Iron, Cobalt and Nitrogen X-Ray Absorption Spectroscopy (XAS) Data Analysis

This project was about analyzing the data of the X-Ray Absorption Spectroscopy (XAS) of several synthesis of modified Onion-like Carbon (OLC) nanoparticles with nitrogen conductive polymers to study different catalysts for the Oxygen Reduction Reaction (ORR). Also, observing differences in the oxidation state, geometry, iron and cobalt bonds, and structures between the samples at different potentials were some of the objectives in this investigation. The PyMca program was used to normalized the samples and transferred the scan’s data. In Athena for the X-Ray Absorption Near Edge Structure (XANES) region, the scans were merged for every sample individually by adjusting the pre-edge, post-edge, spline range in “k”, and the normalization order parameters. Subsequently, Artemis for the Extended X-Ray Absorption Fine Structure (EXAFS) region was used to fit the first and second shell of the samples used in Athena. Here we used a FEFF calculations file from a Cobalt Oxide and Iron Oxide compounds that have similar elements to the ones in our samples. As results, we have been able to fit the N-OLC/FeCo (1:3)-Co and N-OLC/FeCo(1:3)-Fe. In both cases the fits from the first shell were from Co-O and Fe-O bonding interactions and the fits from the second shell were from Co-Co and Fe-Fe bonding interactions between the atoms.

Electrochemical Conversion of Natural Graphite into Carbon Nanostructures for Energy Storage Applications

Natural graphite minerals with global reserves greater than 320 million tones can be considered as low-cost and highly available precursors for the preparation of high-quality carbon nanostructures with potential applications in energy devices and related areas. Here, the electrochemical conversion of natural graphite minerals into carbon nanostructures, comprising onion-like carbon nanoparticles and multiwall carbon nanotubes (MWCNTs) in high-temperature molten salts are studied. The galvanostatic polarization of electrodes made of such minerals is conducted in molten LiCl and LiCl-NaCl at various current densities, leading to the exfoliation of the minerals into carbon nanostructures. The influence of non-carbon impurities present in the natural graphite mineral, and the current density applied on the characteristics of the resultant nanocarbons are investigated. Moreover, the structural and microstructural properties of the nanocarbons fabricated using natural graphite minerals are compared with those produced using commercially pure graphite electrodes. It is found that the electrochemical nanostructuring of the mineral in molten salt not only increases the surface area of the material, but also increases its electrical conductivity. The high-yield conversion of the mineral into carbon nanostructures is realized at the cathode current density of around 1 A cm-2. The Li- and Na- ion storage performances of this sample are evaluated. The Li-ion storage capacity of the sample is found to be remarkable at around 460 mAh g-1 after 500 charge/discharge cycles at the current density of 200 mA g-1. The green molten salt preparation and the electrochemical performance of nanocarbons is discussed here.

Polyacrylonitrile-Coated Onion-like Carbon Nanoparticles for Carbon Nanofibers with Enhanced Strength and Toughness

Polyacrylonitrile-Coated Onion-like Carbon Nanoparticles for Carbon Nanofibers with Enhanced Strength and Toughness

Facile synthesis and excellent microwave absorption performance of ultra-small ZnO-doped onion-like carbon nanoparticles

Ultra-small ZnO-doped onion-like carbon (ZnO-OLC) nanoparticles (NPs) were synthesized by metal organic chemical vapour deposition, and OLC NPs were subsequently obtained by HCl treatment of the as-synthesized ZnO-OLC NPs. For the ZnO-OLC NPs, an optimal reflection loss of −58.7 dB and a wide effective bandwidth of 7.0 GHz were achieved at a very low filler weight loading ratio of 5%; superior to those of OLC NPs. Experimental results and theoretical analyzes indicated that the ZnO dopant could degrade the permittivity and polarization loss of the OLC NPs due to interaction between Zn, O and C atoms, and thus improve their impedance matching and microwave absorption performance. This work provides a new insight into how the ZnO doping affects the microwave absorption performance of OLC NPs from a theoretical point of view, and is expected to be a useful reference for the future design of related microwave absorbers.

Electrolytic Conversion of Natural Graphite into Carbon Nanostructures with Enhanced Electrical Conductivity and Na-ion Storage Performance

This article reports on the electrochemical exfoliation of natural graphite into electrolytic carbon nanostructure (ECN) containing three dimensional clusters of onion-like carbon nanoparticles and carbon nanotubes. The exfoliation process is conducted in molten LiCl-NaCl at 740 °C. The morphological and structural characteristics of ECN are correlated to its electrical and electrochemical performances. Due to the presence of highly graphitized nanotubes, the bulk electrical conductivity of ECN is found to be remarkable at 9.7 S cm−1. Also, an enlarged d002 interlayer spacing is recorded on onion-like carbon nanoparticles present in ECN, enhancing the Na-ion storage performance of the material, with the reversible capacity of 175 mAh g−1 recorded after 385 Na-ion insertion and extraction cycles at the current density of 200 mA g−1. This article discusses the molten salt conversion of natural graphite minerals into nanostructured carbon with enhanced electrical conductivity and Na-ion storage performance.

The local electric field effect of onion-like carbon nanoparticles for improved laser desorption/ionization efficiency of saccharides

It is still a challenge to improve ionization efficiency of saccharides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Herein, the highly curved onion-like carbon nanoparticles (OCS) were synthesized from the low-price candle raw via a facile strategy. The unique nanostructure of OCS showed large surface area with plentiful mesoporous architecture, highly curved sp2 carbon with regulating electronic effect, and good hydrophilicity, which could be beneficial to facilitate the desorption and ionization efficiency in MS process. The prepared OCS material as MALDI matrix exhibited the superior performance for the detection of xylose, glucose, maltose monohydrate, and raffinose pentahydrate in positive-ion mode with low background noise, enhanced ion intensities, uniform distribution, excellent reproducibility, good salt-tolerance, and high sensitivity compared to control candle soot (CS) and traditional α-cyano-4-hydroxycinnamic acid (CHCA) matrices. This highly effective LDI of OCS matrix was attributed to its enhancing local electric field effect, strong UV absorption ability, and high photo-thermal conversion performance. Furthermore, the OCS-assisted LDI MS approach was employed to quantitatively detect glucose in rat serum. This LDI MS platform may have valuable for the analysis of metabolites in clinical research.

Assessment of Potential Toxicity of Onion-like Carbon Nanoparticles from Grilled Turbot Scophthalmus maximus L.

Although the presence of foodborne nanoparticles was confirmed in grilled fish in a previous study, the evaluation of potential health risks of these NPs was insufficient. In the present study, the potential toxicity of onion-like carbon nanoparticles (OCNPs) separated from grilled turbot Scophthalmus maximus L. was evaluated using mouse osteoblasts cells model and zebrafish (Danio rerio) model. Cytotoxicity evaluation revealed that the OCNPs penetrated into the MC3T3-E1 cells without arousing cell morphology changes. No evident apoptosis or damage of cells was observed with increasing OCNPs’ concentration to 20 mg/mL. In the hemolysis test, OCNPs did not show an obvious hemolysis effect on red blood cells. In the acute toxicity test, the LC50 value (212.431 mg/L) of OCNPs to zebrafish showed a weak acute toxicity. In subacute toxicity test, after exposure to OCNPs (30 mg/L, 40 mg/L) for 10 days, a significant increase of reactive oxygen species level of zebrafish was observed. Meanwhile, redundant ROS content caused inhibition to several antioxidant enzymes and induced lipid and protein peroxidation damages according to the upregulation of malondialdehyde and protein carbonyl levels. The chronic toxicity test results indicated that oxidative stress was only observed in the high concentration group of OCNPs-treated zebrafish.

Noise and Electrical Characteristics of Composites Filled with Onion-like Carbon Nanoparticles.

Polymer matrix composites filled with carbon nanoparticles are promising materials for many applications, but their properties strongly depend on the particle features, concentration and distribution within the matrix. Here we present a study of the electrical resistivity and the low-frequency voltage fluctuation of composites based on epoxy resin filled with onion-like carbon (OLC) of different sizes (40–250 nm) above the percolation threshold, which should clarify the electrical transport characteristics in these materials. Electrical measurements were performed in the temperature range of 78 to 380 K, and voltage noise analysis was carried out from 10 Hz to 20 kHz. At low temperatures (below 250 K), thermally activated tunneling, variable-range hopping and generation–recombination of charge carriers take place. Above 250 K, the rapid expansion of the matrix with the temperature increases the resistivity, but above ~330 K, the conductivity of the matrix becomes significant. Quasi one-dimensional electrical transport is observed in composites with the smallest particles (40 nm), while in composites with the largest particles (220–250 nm), the dimensionality of the electrical transport is higher. The temperature dependence of the electrical conductivity of composites with smaller particles is more sensitive to matrix expansion.

Upgrading of diesel engine exhaust waste into onion-like carbon nanoparticles for integrated degradation sensing in nano-biocomposites

Onion-like carbon nano particles are separated from diesel engine exhaust “pollutant soot” and used in the structural health monitoring of a biocomposite.