Carbon Nano-onions Research Articles

Sonochemical Synthesis of Potassium-Intercalated Carbon Allotropes: Bulk Formation at Ambient Room Temperature.

Intercalation can be used to alter the electronic properties of graphitic materials. Intercalation is, however, a notoriously brute-force process typically carried out at a high temperature in an inert environment for an extended period. As an exception to this, a simple sonication-assisted intercalation of potassium into graphite at ambient room temperature (RT) has been reported. Here we extend this approach to intercalation of potassium into other carbon allotropes, including planar graphene nanoplatelets (GNPs) and curved graphitic tubes and shells, such as multiwalled carbon nanotubes (MWCNTs) and nanodiamond-derived carbon nano-onions (NCNOs). We report the rapid room-temperature sonication-assisted potassium metal intercalation of GNPs, MWCNTs, and NCNOs. Powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and electron dispersive X-ray spectroscopy (EDS) were used to visualize the location of potassium in the intercalated products.

Sustainable rubber nanocomposites for hydrogen sealings: Impact of carbon nano-onions and bio-based plasticizer

Additives play a crucial role in modifying and enhancing the properties of rubbers, improving mechanical strength, thermal stability, and chemical resistance to make them more suitable for various applications. The rubber industry faces challenges related to high resource consumption and toxic emissions, which are further impacted by the use of performance-enhancing additives. In hydrogen storage systems, tailored additives are required for rubbers to withstand elevated temperatures and high pressures, preventing hydrogen-induced swelling, a major cause of sealing failure. Herein, a novel form of carbonaceous material, carbon nano-onions (CNOs), and the bio-based plasticizer additive epoxidized soybean oil (ESO) are utilized in conventional silica-filled nitrile butadiene rubber (NBR) nanocomposites to develop low-carbon manufacturing high pressure hydrogen resistant O-rings for sealing applications. The results reveal that the incorporation of CNOs increases the crosslinking density (vc), assisted by ESO, in silica-filled NBR nanocomposites. While the conventional adipate-based plasticizer and ESO were found to be susceptible to high pressure hydrogen exposures, ESO demonstrated sustained compressive sealing properties with increase in von-Mises stress and in elevated thermo-oxidative conditions over time. The results of the life cycle assessment (LCA) recommend ESO for low-carbon manufacturing in rubber processing over conventional plasticizer.

Stacking Fault Nucleation in Films of Vertically Oriented Multiwall Carbon Nanotubes by Pyrolysis of Ferrocene and Dimethyl Ferrocene at a Low Vapor Flow Rate

Recent observations of superconductivity in low-dimensional systems composed of twisted, untwisted, or rhombohedral graphene have attracted significant attention. One-dimensional moiré superlattices and flat bands have interestingly been identified in collapsed chiral carbon nanotubes (CNTs), opening up new avenues for the tunability of the electronic properties in these systems. The nucleation of hexagonal moiré superlattices and other types of stacking faults has also been demonstrated in partially collapsed and uncollapsed carbon nano-onions (CNOs). Here, we report a novel investigation on the dynamics of stacking fault nucleation within the multilayered lattices of micrometer-scale vertically oriented films of multiwall CNTs (MWCNTs), resulting from the pyrolysis of molecular precursors consisting of ferrocene or dimethyl ferrocene, at low vapor flow rates of ~5–20 mL/min. Interestingly, local nucleation of moiré-like superlattices (as stacking faults) was found when employing dimethyl ferrocene as the pyrolysis precursor. The morphological and structural properties of these systems were investigated with the aid of scanning and transmission electron microscopies, namely SEM, TEM, and HRTEM, as well as X-ray diffraction (XRD) and Raman point/mapping spectroscopy. Deconvolution analyses of the Raman spectra also demonstrated a local surface oxidation, possibly occurring on defect-rich interfaces, frequently identified within or in proximity of bamboo-like graphitic caps. By employing high-temperature Raman spectroscopy, we demonstrate a post-growth re-graphitization, which may also be visualized as an alternative way of depleting the oxygen content within the MWCNTs’ interfaces through recrystallization.

Elastic Wave Propagation in 2D Carbon Nano‐Onion Lattices

AbstractThis study presents a simple analytical model to investigate wave propagation in 2D carbon nano‐onions (CNOs) and nitrogen‐doped carbon nano‐onions (N‐CNOs) lattices. Furthermore, the dispersion relationships of the waves and bandgaps in these lattices are derived based on Bloch's theorem. The CNOs and N‐CNOs lattices are modeled as infinite 2D mass‐in‐mass structures accurately assembled using linear springs. The Lennard–Jones potential energy is employed to obtain equivalent spring constants. A key finding of this research is the identification of bandgaps within all lattice structures, signifying regions where wave propagation is prohibited. The existence of these bandgaps offers potential for the advancement of adjustable nano‐scale metamaterials.

Portable multimodal platform with carbon nano-onions as colorimetric and fluorescent signal output for trypsin detection

Multimodal biosensors with independent signaling pathways can self-calibrate and improve the reliability of disease biomarker detection. Herein, a colorimetric-fluorescent dual-mode paper-based biosensor with PAN/Fe(III)–CNOs (FPCs) as core components has been developed, which information is recognized by smartphone and naked eye. Using 1-(2-pyridylazo)-2-naphthol (PAN) as a mediator, Fe(III) is enriched on the surface of carbon nano-onions (CNOs), endowing FPCs with excellent mimetic enzyme activity and photothermal conversion ability, which allows it to output amplified colorimetric signals under laser irradiation. In addition, the complexation of PAN with Fe(III) broadens its absorption spectrum, which makes FPCs more suitable to be energy acceptors to quench fluorescence of polymer dots (Pdots), resulting in the changes of output fluorescent signal. Based on the above design, a portable colorimetric-fluorescent dual-mode biosensor is proposed for trypsin detection with Pdots as fluorescence sources and FPCs as fluorescence quenchers and nanoenzymes. This work provides a convenient way for constructing portable visual multimodal biosensors, which is expected to applied in various disease diagnosis.

Room-temperature synthesis of carbon nano-onions by B4C sonication in water

Room-temperature synthesis of carbon nano-onions by B4C sonication in water

Room-temperature synthesis of carbon nano-onions by B<sub>4</sub>C sonication in water

Room-temperature synthesis of carbon nano-onions by B<sub>4</sub>C sonication in water

Facile chemical vapor deposition (CVD) method for synthesis of high purity carbon nano-onions

Multi-layered fullerenes, known as “carbon nano-onions,” are attractive for various applications due to their shape, size, and surface area. A standard method usually uses powder catalysts, which require an additional step to separate and purify nano-onions after their synthesis. In this work, a simple method based on chemical vapor deposition and a copper foil as a catalyst has been developed. The effect of growth time on the structural, chemical, and morphological properties of nano-onions was investigated. The results indicate that carbon nano-onions with different degrees of graphitization, diameters, and thermal stability are obtained independently of the growth time.

Evaluation of chitosan composites with functionalized carbon nano-onions for supercapacitor applications

The growing need for devices boasting substantial energy and power storage capabilities, like capacitors, is driving extensive research and development efforts toward novel materials endowed with superior electrochemical properties. An example of a promising material in this field is found in carbon nanoonions (CNOs). These carbon-based nanostructures boast remarkable properties such as high conductivity, surface area, and stability. Unfortunately, their low energy density and capacitance act as a hindrance to their potential electrochemical application. To bypass this issue, chemical treatment is often employed as a means to improve the sorption processes and, thus, optimize the charge/discharge dynamics. Herein, three types of materials were prepared using commercially available chitosan (Chit) and unfunctionalized carbon nano-onions (p-CNOs), as well as functionalized CNOs with carboxylic fragments (ox-CNOs) and benzoic groups (benz-CNOs). The capacitance of each material was evaluated through cyclic voltammetry using different electrolytes (1.0 M), obtaining values of 34.1, 23.7, 14.1, 43.0, 59.3, and 36.2 Fg-1 for p-CNOs, benz-CNOs, ox-CNOs, p-CNOs/Chit 2:1, benz-CNOs/Chit 2:1, and ox-CNOs 3:1, respectively in Na2SO4, and for the composite p-CNOs/Chit 2:1 in MgSO4, with a specific capacitance of 43.0 Fg-1. We also used electrochemical impedance spectroscopy (EIS) to study the charge/discharge process at the electrodes, concluding that the fragments of the electron-withdrawing groups in the materials improved their electrochemical properties without compromising other intrinsical properties.

Sr and Fe-Substituted LaMnO3 Perovskite for High-Rate Asymmetric Hybrid Supercapacitors

Perovskite has been getting significant attention in solar cells, photocatalysts, and hybrid supercapacitors. The symmetry or structural stability of ABO3-type perovskite oxides depends mainly on the size of ‘A’ and ‘B’ cations, which determines the material properties. The partial substitution of these cations may be used to tune these properties. The ionic sizes and valence states of the cations play an important role in improving the properties of perovskite. In this study, the substitution of La3+ with Sr2+ with a larger ionic radius and Mn3+ with Fe3+ with a similar ionic radius favored both the crystal symmetry and the mixed ionic-electronic conductivity of the perovskite. Electrodes based on La0.7Sr0.3Mn0.5Fe0.5O3 (LSMFO55) exhibited a faradaic behavior with a specific capacity of 330 C g-1 (92 mAh g-1) at a 12C rate, while this electrode maintained a capacity of 259 C g-1 at 240C (charge or discharge in 15s). Additionally, exohedral carbon nano-onions (CNO) were introduced as a negative electrode to design an asymmetric hybrid supercapacitor (AHS) with a widened cell voltage. The use of CNO as a negative electrode in the AHS improved the rate capability drastically compared to rGO. This device maintained a good energy density even at an extra-high charging rate (600C), owing to its outstanding rate capability. The high-rate performance of the LSMFO55//CNO AHS can be elucidated by successful fabrication with a mixed ionic-electronic conductive positive electrode and a CNO negative electrode. Tuning the electronic and ionic conductivities by cationic substitution and introducing CNO negative electrodes can provide a practical high-rate hybrid device using various perovskites.

Electrochemical sensor based on mesoporous g-C3N4/N-CNO/gold nanoparticles for measuring oxycodone

Oxycodone, often used as an analgesic, is a potent opioid. While its effectiveness has been proven in the control of moderate to acute pain, excessive use of oxycodone imposes heart failure, heart palpitations, reduction of red blood cells, bone pain, and even death. Therefore, monitoring the oxycodone concentration in blood is vital for emergency care. For this purpose, a novel electrochemical sensor was designed based on a glassy carbon electrode modified with mesoporous g-C3N4 (M-C3N4), carbon nano-onions doped with nitrogen (N-CNO), and gold nanoparticles. At first, the SEM and XRD techniques were employed to characterize prepared M-C3N4 and N-CNO samples. The electro-oxidation behavior of the oxycodone was evaluated by cyclic and differential pulse voltammetric methods. Based on the influence of the potential scanning rate and solution pH on the voltammetric response of oxycodone oxidation, a redox mechanism was proposed. A 16 nM detection limit was acquired for the oxycodone analysis with a linear response in the 0.05–150 µM range. This sensor showed a remarkable ability for oxycodone detection in plasma samples. The long-term stability, superior selectivity, and reproducibility of this sensor prove its ability to measure oxycodone accurately and precisely in authentic spices.

Waste-Derived Carbon Nano-Onions for the Removal of Organic Dye from Wastewater and Phytotoxicity Studies.

Dyes are extensively employed in industries, namely, textiles, cosmetics, paper, pharmaceuticals, tanning, etc. The effluent released from these industries contains various kinds of harmful dyes that adversely impact living beings and the environment due to their recalcitrant and toxic nature. In this study, an effort has been made to eliminate the methylene blue (MB) from wastewater using carbon nano-onions (CNOs) produced from waste frying oil (WFO) using an economical and eco-friendly wick pyrolysis method. The impact of process variables, namely, pH, temperature, process time, MB dye concentration, and adsorbent, was examined for optimum dye removal. The dye removal efficiency (RE) of 99.78% was obtained in 20 min under optimum conditions. The pseudo-second-order model demonstrated a better kinetic fitting with the experimental data. The Langmuir model represented the maximum adsorption capacity (q max) of 43.11 ± 2.56 mg g-1. The regeneration studies demonstrated that the CNOs achieved ∼99.6% MB dye removal over three cycles. Brassica nigra seeds irrigated in treated wastewater showed better growth (3.29 cm) than untreated dye wastewater, which confirms the environmental sustainability of the overall process.

New Zein Protein Composites with High Performance in Phosphate Removal, Intrinsic Antibacterial, and Drug Delivery Capabilities.

Herein, poly(N-(4-aminophenyl)methacrylamide)-carbon nano-onions [abbreviated as PAPMA-CNOs (f-CNOs)] integrated gallic acid cross-linked zein composite fibers (ZG/f-CNOs) were developed for the removal/recovery of phosphate from wastewater along with controlled drug delivery and intrinsic antibacterial characteristics. The composite fibers were produced by Forcespinning followed by a heat-pressure technique. The obtained ZG/f-CNOs composite fibers presented several favorable characteristics of nanoadsorbents and drug carriers. The composite fibers exhibited excellent adsorption capabilities for phosphate ions. The adsorption assessment demonstrated that composite fibers process highly selective sequestration of phosphate ions from polluted water, even in the presence of competing anions. The ZG/f-CNOs composite fibers presented a maximum phosphate adsorption capacity (qmax) of 2500 mg/g at pH 7.0. This represents the most efficient phosphate adsorption system among all of the reported nanocomposites to date. The isotherm studies and adsorption kinetics of the adsorbent showed that the adsorption experiments followed the pseudo-second-order and Langmuir isotherm model (R2 = 0.9999). After 13 adsorption/desorption cycles, the adsorbent could still maintain its adsorption efficiency of 96-98% at pH 7.0 while maintaining stability under thermal and chemical conditions. The results mark significant progress in the design of composite fibers for removing phosphates from wastewater, potentially aiding in alleviating eutrophication effects. Owing to the f-CNOs incorporation, ZG/f-CNOs composite fibers exhibited controlled drug delivery. An antibiotic azithromycin drug-encapsulated composite fibers presented a pH-mediated drug release in a controlled manner over 18 days. Furthermore, the composite fibers displayed excellent antibacterial efficiency against Gram-positive and Gram-negative bacteria without causing resistance. In addition, zein composite fibers showed augmented mechanical properties due to the presence of f-CNOs within the zein matrix. Nonetheless, the robust zein composite fibers with inherent stimuli-responsive drug delivery, antibacterial properties, and phosphate adsorption properties can be considered promising multifunctional composites for biomedical applications and environmental remediation.

Easy functionalization of carbon nano-onions with disulfides and their use as recyclable heterogeneous organocatalysts

A facile functionalization of carbon nano-onions (CNO), through an atom economical one-step process, with a series of different generation (2.0, 2.5, and 3.0G) poly(amidoamine) (PAMAM) dendrimers with a cystamine core and endowed with either methyl ester or amino groups in the periphery has been reported. The radical addition reaction onto CNO surface, after the homolytic rupture of the S–S bond of cystamine, afforded CNO-PAMAM hybrids, which were extensively characterized using various analytical and spectroscopic techniques such as thermogravimetric analysis (TGA), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, solid state 13C NMR, Raman, X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and zeta potential (ZP). Morphological and textural properties were also investigated by high-resolution transmission electron microscopy (HRTEM) analysis and N2 adsorption/desorption isotherms. Furthermore, the presence and availability of –NH2 groups has been demonstrated by applying the functionalized CNO with PAMAM 2.0G and 3.0G as heterogeneous and recyclable organocatalysts in the one-pot three-component synthesis of 2-amino-4H-chromene derivatives.

Studies on the Catalytic Properties of Palladium–Niobium Electrocatalysts Supported on Carbon Nano-onions toward Isopropanol and Ethanol Electro-oxidation in an Alkaline Medium

Studies on the Catalytic Properties of Palladium–Niobium Electrocatalysts Supported on Carbon Nano-onions toward Isopropanol and Ethanol Electro-oxidation in an Alkaline Medium

Carbon nanomaterials: Pioneering innovations in bioimaging and biosensing technologies

Carbon-based nanomaterials, including carbon nanotubes, graphene, carbon dots, carbon nano onions, and carbon nano horns, exhibit exceptional properties such as high electrical and thermal conductivity, mechanical strength, and biocompatibility. These characteristics make them attractive for various biomedical applications, particularly in bioimaging and biosensing. In bioimaging, carbon-based nanomaterials offer several advantages. Their unique properties enable precise imaging of biological events in cells, tissues, and organs, with minimal interference in living processes. By leveraging these properties, researchers can achieve high-resolution imaging for accurate diagnosis and therapy. Similarly, carbon-based nanomaterials are crucial in biosensing applications. They provide a platform for developing highly sensitive biosensors due to their distinctive electrical properties and surface characteristics. Functionalizing these nanomaterials with specific biomolecules or receptors allows for the detection and extraction of target molecules with exceptional precision and sensitivity, inspired by principles found in living systems. A review article focusing on the applications of carbon-based nanomaterials in bioimaging and biosensing would provide insights into their potential in advancing biotechnology. This article discusses a variety of carbon-based nanomaterials, including carbon nanotubes, graphene, carbon dots, carbon nano onions, and carbon nano horns, emphasizing their unique properties and applications in bioimaging and sensing. The review emphasizes the importance of detection accuracy and sensitivity in biomedical applications and investigates how carbon-based nanomaterials help to advance biotechnology. This exploration will allow researchers to explore and create novel diagnostic and therapeutic methods.

Strategic Way of Synthesizing Heteroatom-Doped Carbon Nano-onions Using Waste Chicken Fat Oil for Energy Storage Devices.

An easy way of synthesizing low-cost carbon nanomaterials without the need for high-temperature processing approach is critical for energy storage applications because the demand has increased for affordable, long-term, and environmentally friendly synthesized carbon-based materials. Herein, we synthesized multilayered graphitic carbon nano-onions (CNOs) using an oil-wick flame pyrolysis approach, employing biowaste (chicken fat) oil as a cost-effective precursor. The prepared CNOs can provide enhanced ion movement and less resistance for electron transport by interconnecting CNO particles with one another. Furthermore, heteroatom (S,N)-doped CNOs (h-CNOs) were synthesized to optimize the hydrophilic and conductive properties of carbon materials, which eventually exalted the capacitive charge transfer kinetics. The h-CNOs demonstrated superior, highest specific capacitance of 261 F/g, while the undoped CNOs showed a capacitance of 180.6 F/g at a current density of 1 A/g. In addition to capacitance, the h-CNOs also demonstrated a rate capability of 69% and a good cycling stability of 97.5% under high current densities. An asymmetric supercapacitor was fabricated using the h-CNOs as the negative and MnCo2S4 (MCS) as the positive electrode. The device showed high energy and power performance of 32.8 Wh/kg and 7350 W/kg, respectively, with a capacitance retention of 97% over 5000 cycles. Considering the facile strategic way to produce novel carbonaceous materials derived from biowaste oil (chicken fat oil), this could be considered a potential advantage for commercial energy storage devices and may open the door to producing inexpensive, industrially revolutionizing energy storage devices.

Superior performance of N-doped carbon Nanoonions/Nafion based microfluidic electrochemical Cd2+ sensor when compared to Screen-Printed Carbon-Based electrode devices

The sensing of cadmium is important due to its highly toxic effects on various organs of humans and animals. Commonly employed are screen-printed carbon-based electrodes (SPCE) as suitable low-cost sensing platform. Microfluidic electrochemical sensor (μCS) can also be portable, highly sensitive, and low-cost but are up to now only seldom studied and applied. Here we demonstrate the superior performance of μCS over SPCE arrangements for sensing ultra-trace of Cd2+. Additionally, N-doped carbon nanoonions (N-CNOs) are introduced as sustainable non-metallic modifier and employed for both sensing arrangements. The study depicted that employing the modifier the electrochemically active surface area and the electron transfer rate in both arrangements is improved together with improve sensitivity. Both arrangements were compared using cyclic voltammetry and electrochemical impedance spectroscopy in [Fe(CN)6]3−/4−, and also square-wave anodic stripping voltammetry (SWASV) for Cd2+ sensing. The µCS arrangement clearly outperforms the SPCE arrangement in signal strength. For the final device (μCS modified with N-CNOs) a linear concentration range from 1.0 to 100 μg L−1 was achieved. The limit of detection and sensitivity resulted to 0.25 μg L−1 and 1.02 μA µg−1 L cm−2, respectively. Besides this excellent sensitivity combines with high stability, which was tested for 8 repetitive measurements with a single device resulting in high reproducibility. Additionally, this procedure was favorably employed for measurements of Cd2+ in different real samples, which demonstrated the excellent applicability of the device for the adsorption and detection of heavy metal ions.

Enhanced electrochemical energy storage devices utilizing a one-dimensional (1D) α-MnO2 nanocomposite encased in onion-like carbon

AbstractThis work describes the fabrication of a novel one-dimensional (1D) α-MnO2 nanorods encased in onion-like carbon (or) carbon nano-onions (OLC) via microwave irradiation techniques employing electrolytic manganese dioxide (EMD), which is especially beneficial for rapid ion and electron transfer, and great structural stability. The composite of α-MnO2 and OLC demonstrates exceptional performance as an electrode across various electrochemical energy storage systems, including zinc-ion batteries (ZIB), sodium-ion batteries (SIB), and supercapacitors (SC) than the pristine α-MnO2. In SIB systems, the composite exhibits a specific capacity of 266 mAh g−1 at initial cycle with 50% capacity retention over 500 cycles, whereas the pristine electrode delivers only 39% capacity retention. The rapid yet controlled charge transfer kinetics facilitated by OLC addition in the α-MnO2 matrix outperforms as the ZIB cathode with an excellent specific capacity of 476 mAh g−1 with 100% capacity retention, while the pristine sample exhibits 77.5% capacity retention. As a SC electrode, the α-MnO2/OLC composite exhibits better electrochemical properties such as rectangular behavior, increased specific capacitance (792 F g−1), excellent capacity retention at high current densities, and others. The higher surface area that could be offered by the OLC to the α-MnO2 matrix facilitates the improved electrochemistry in the pristine sample and this kind of modification can be a viable solution to overcome the limitations of α-MnO2 for electrochemical energy storage applications. It is important to note that the performance outputs of α-MnO2/OLC composite are far better than the regular carbon (graphite, graphene) in α-MnO2 electrodes. Further, OLC provided with high surface area and ordered morphology can play the role of conductivity booster, structural stabilizer, and electrochemical active material in all the energy storage applications which may give a significant research attention in near future.

Biodegradability of Carbon Nano‐Onions by Human Myeloperoxidase and Photo‐Fenton Process

The biodegradability of carbon nanomaterials (CNMs) in the environment and organisms needs to be understood, and it is highly essential to estimate their in vivo fate, especially for clinical applications. It is also important to investigate their metabolites formation to fully understand their biocompatibility. Herein, we explored the biodegradability of multilayer fullerenes, better known as carbon nano‐onions (CNOs), by treating them with human myeloperoxidase (hMPO) isolated from the neutrophils, plant enzyme horseradish peroxidase (HRP) and the photo‐Fenton (PF) reaction. High‐resolution electron microscopy (HRTEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and mass spectrometry (MS) results confirmed that CNOs are not bio‐persistent. Moreover, these results indicate that the oxidized (functionalized) CNOs can undergo faster biodegradation than the pristine CNOs. The possible by‐products of biodegradation of CNOs were characterized using mass spectrometry. An understanding of the biodegradation properties of CNOs and their metabolites is fundamental for future biomedical applications.