Tiny Carbon Research Articles

Integration of Carbon-Based Nanomaterials for Hybrid Energy Storage in Lithium-Ion Batteries

Hybrid energy storage systems benefit significantly from incorporating nanoparticles containing metallic oxides, potassium phosphate, chemical compounds, and sulfides. The current technological problem is to increase the device’s electrical capacity without decreasing its energy capacity. The energy storage capacity of lithium-ion cells has been greatly improved by the use of tiny carbon particles owing to their conductive qualities, extensive specific surface area, customizable form, and intrinsic resilience. Further biologically active layouts, thinner ion-diffusion dimensions, and increased aboard carrier-/charge-transport motion are all made possible by incorporating effective bi-dimensional nanomaterials into future-oriented battery packs. For applications like lithium-ion batteries and electrochemical capacitors, this research presents carbon-based energy storage (CES) using a support vector machine (SVM) incorporating Particle Swarm Optimization (CES-SVM) to investigate the long-term stability of nanoparticle alloy forms of a specific shape and chemical makeup. This paper provides a potential improvement to the intermittent particle swarm optimization technique and its accompanying algorithmic architecture. Hybrid nanocomposites have been successfully synthesized, allowing the easy synthetic pathway and unique growth of nanostructuring technology to be used for electrodes with outstanding electrochemical effectiveness in conventional lithium-ion batteries. This paper shows how the cell’s conductivity, the electrode/electrolyte contact, and ion diffusion all affect impedance performance. Carbonaceous electrodes for lithium-ion battery systems, electrochemical storage units, and related combination devices are examined as a final area.

Simple synthesis of water-soluble ruthenium carry CDs as admirable probe for improved environment and biological applications

Metal-doped carbon dots (M-CDs) are brand-new 0-D nanomaterial that affords multiple guaranteed properties because of metals in between tiny carbon matrices. However, preparing M-CDs without aggregation of metals is very challenging. Here, we proposed a new tactic method to prepare highly water-soluble ruthenium Ru(Ⅱ)-holding CDs (Ru@CDs) through a one-step microwave-assisted approach with quantum yield of 19.21% using ruthenium chloride and ethylene diamine without any solvents. The optical, surface, structural, and morphological features were deeply evaluated with the support of UV–vis, photoluminescence, Fourier-transform infrared, Raman, X-ray diffraction, transmission electron microscope, and X-ray photoelectron spectroscopy techniques. The excellent photoluminescent and water-soluble properties of Ru@CDs were employed to individually detection of dual carcinogenic environmental toxic metal ions through the photoluminescence technique. They detected the lower limit of 0.128 μM as Cr6+ and 0.328 μM as Hg2+ in the aqueous environment, which was very low compared to CDs. Followed by Ru@CDs, embedded cost-efficient filter paper was fabricated for real-time visual recognition of Cr6+ and Hg2+ ions in water. Significantly, Ru@CDs show good cytotoxicity and effective growth inhibition against cancer cells compared to CDs. So, the Ru@CDs were employed as an effective bioimaging agent selectively. To conclude, facile synthesized Ru@CDs explore its multifunctional quality as a better environmental pollutant detector and bioimaging agent.

Testing New Materials to Deliver Medicine to Sick Bones

Bones are the building blocks of our skeletons—they give our bodies structure and allow us to walk, dance, and pick things up. Healthy bones are strong, lightweight, hard, and even able to fix themselves when they get worn out or damaged. But if bones get sick, they can no longer repair themselves and they start to break down. One disease that makes bones sick is called osteoporosis and it can be very painful. Currently, doctors cannot cure osteoporosis. While there are medications to slow bone loss, there are no safe treatments to repair bone that is already damaged. Therefore, doctors and scientists are working together to find ways to prevent and even cure diseases like osteoporosis. One important challenge that needs to be addressed is: how can medicine be delivered to sick bones? In this article, we discuss how tiny carbon nanoparticles could help doctors deliver medicine to sick bones to repair them.

Surface relaxation determine the band bending and special optical properties of carbon nanodots

Carbon nanodots (CDots) are frequently adopted to modify composite photocatalysts, due to their unique optical properties and adjustable band structure. Here, an ab initio approach based on extend Hückel theory is used to study in detail the dependent relationship between the optical properties of carbon nanodots and surface relaxation. In order to imitate the surface structure of carbon nanodots, a number of two-layer tiny carbon domains are used. The energy level distribution shows a clear band gap, demonstrating the features of semiconductor. The band structure is somewhat bent as a result of surface relaxation's dramatic effect on the highest occupied molecular orbital (HOMO). The ultraviolet and visible absorption spectra of carbon nanodots are successfully predicted in theory, by considering the oscillator strength in every possibility transition, and the transition from the valence band maximum (VBM) to conduction band minimum (CBM) is the main peak location. The surface relaxation results in red shift of the spectral lines, which is the potential reason why carbon nanodots promote visible light absorption.

Enhancement in Electromagnetic Wave Shielding Effectiveness through the Formation of Carbon Nanofiber Hybrids on Carbon-Based Nonwoven Fabrics.

The selective hybrid formation of numerous tiny carbon nanofibers (CNFs) in carbon-based nonwoven fabrics (c-NFs), namely CNFs formed only on the surfaces of individual carbon fibers (i-CFs) constituting c-NFs and not on the surfaces of carbon microcoils (CMCs), could be formed by the incorporation of H2 gas flow into the C2H2 + SF6 gas flow in a thermal chemical vapor deposition system. On the other hand, the nonselective hybrid formation of numerous tiny CNFs in c-NFs, that is, tiny CNFs formed on the surfaces of both i-CFs and CMCs, could be achieved by simply modulating the SF6 gas flow on and off in continuous cycles during the reaction. Detailed mechanisms are suggested for the selective or nonselective formation of tiny CNFs in c-NFs. Furthermore, the electromagnetic wave shielding effectiveness (SE) values of the samples were investigated across operating frequencies in the 8.0–12.0 GHz range. Compared with previously reported total SE values, the presently measured values rank in the top tier. Although hybrid formation reduced the electrical conductivity of the native c-NFs, the total SE values of the native c-NFs greatly increased following hybrid formation. This dramatic improvement in the total SE values is ascribed to the increased thickness of c-NFs after hybrid formation and the electromagnetic wave absorption enhancement caused by the intrinsic characteristics of CMCs and the numerous intersections of tiny CNFs.

Polymeric carbon dot/boehmite nanocomposite made portable sensing device (Kavach) for non-invasive and selective detection of Cr(VI) in wastewater and living cells

This work reports a handheld fluorometric probe, namely ‘Kavach’ for monitoring hexavalent chromium in industrial wastewater and living systems. Kavach is capable to detect chromium contamination in a rapid and facile way. The device is made of a thin layer (~1 mm) of carbon dot decorated boehmite nanostructure (BH@CD) incorporated in a layer of poly vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) membrane. The doped membrane has an excellent blue fluorescence upon UV excitation (355 nm) and alters its fluorescence level when exposed to Cr(VI). In reality, tiny carbon dots leach out from the nano-matrices to produce secondary contamination. Incorporation of the BH@CD into the polymeric matrix of PVDF-HFP significantly reduces such contamination and makes this material a potential sensing probe. This photoinduced electron transfer (PET) based sensor is tremendously selective and sensitive (LOD ~66 nM) towards aqueous chromium. The performance of the probe remains unaltered in different pH and water qualities. Additionally, this material can sense chromium in living cells, which has been validated theoretically using molecular docking and observed experimentally using fluorescence microscopy. Kavach is truly a handheld, reusable and non-invasive sensing probe against Cr(VI), which can be employed for on-site low-cost detection.

Graphite Ion Source Geometry and Ne-Gas Pressure Dependent Growth and Morphology of Carbon Nanoclusters: AFM Analysis

The understanding of the growth and morphological evolution of nanoclusters with process parameters such as ion source geometry, voltage, current, time, and gas pressure are highly important to achieve their desired sizes, morphology, and concentration. Carbon nanoclusters (0-dimensional) were synthesized using the DC glow discharge technique at different process parameters (such as Ne-gas pressures, current, voltage, etc.) using custom fabricated graphite ion sources of cylindrical and U-shaped geometries. The morphology and density of carbon nanoclusters were studied with an atomic force microscope (AFM) to understand their evolution at different process parameters. The study suggests that the U-shaped hollow cathode ion source produces tiny carbon nanoclusters at greater concentration as compared to the cylindrical cathode. Similarly, the density of tiny nanoclusters enhances greatly with the increasing pressures (e.g., 75 mbar). In addition, the AFM morphology of the nanoclusters shows that they are more agglomerated at relatively lower pressure (e.g., 25 mbar). This may be due to the higher fragmentation of carbon soot with the increasing pressure because of more collisions among gas molecules and carbonaceous species. At controlled and optimized Ne-gas pressures and source geometry, carbon nanoclusters of the desired sizes can be fabricated, which may become promising candidates for nanoscale electronics, optoelectronic, and spintronic devices.

DNA-damage and cell cycle arrest initiated anti-cancer potency of super tiny carbon dots on MCF7 cell line

While carbon-based materials have spearheaded numerous breakthroughs in biomedicine, they also have procreated many logical concerns on their overall toxicity. Carbon dots (CDs) as a respectively new member have been extensively explored in nucleus directed delivery and bioimaging due to their intrinsic fluorescence properties coupled with their small size and surface properties. Although various in vitro/in vivo studies have shown that CDs are mostly biocompatible, sufficient information is lacking regarding genotoxicity of them and underlying mechanisms. This study aims to analyze the real-time cytotoxicity of super tiny CDs (2.05 ± 0.22 nm) on human breast cancer cells (MCF7) and human primary dermal fibroblast cell cultures (HDFa) by xCELLigence analysis system for further evaluating their genotoxicity and clastogenicity to evaluate the anti-tumor potential of CDs on breast adenocarcinoma. As combined with flow cytometry studies, comet assay and cytokinesis-block micronucleus assay suggest that the CDs can penetrate to the cell nuclei, interact with the genetic material, and explode DNA damage and G0/G1 phase arrest in cancer cells even at very low concentrations (0.025 ppm) which provide a strong foundation for the design of potentially promising CD-based functional nanomaterials for DNA-damage induced treatment in cancer therapy.

Aldehyde-conjugated chitosan-graphene oxide glucodynamers: Ternary cooperative assembly and controlled chemical release

Simultaneous condensation of aromatic aldehydes (ArxCHO; x = 1–4) on chitosan biopolymer (CS) affords, after water-evaporation, structurally-conjugated aryl-functionalized CS-Arx-f films. Similarly, cooperative assembly of two-dimensional nanometric graphene oxide (GO), aromatic aldehyde and chitosan provides transparent, flexible and crack-free aldehyde-functionalized, ternary-reinforced CS-Arx-GO-f nanocomposite films. Homogenous films were obtained using ortho-hydroxybenzaldehyde Ar1 while the para-hydroxybenzaldehyde Ar4 was prone to packing inside. Textural and mechanical properties were investigated and expectedly, significant improvement was found for CS-Ar1-GO-f because of the great dispersion of the aromatic and the presence of the filler. The sensitivity of unsaturated CN imine bond to hydrolysis was explored for triggering controlled release of aromatics from the as-prepared films. All of them were found to induce a time-dependent aromatic release. It has been moreover observed that the release was significantly delayed in CS-Arx-GO-f compared to CS-Arx-f, a fact attributed to the interplay of the ring with the basal and edges of graphene oxide, through π-π stacking and additional hydrogen bonding interactions. This finding shows that beyond the conventional wisdom using fillers for improving thermal and mechanical properties, the tiny carbon sheets can act as a regulator for aldehyde release, thereby providing a way for more controlled chemical delivery from confined nanocomposites.

Carbon pillars are stronger than diamond yet elastic

Researchers have constructed microscopic carbon structures that boast the best combination of strength and elasticity of any material studied to date (Nat. Nanotechnol. 2019, DOI: 10.1038/s41565-019-0486-y). The tiny carbon pillars are stronger by weight than most existing materials and can bounce back after being pressed to half their size. The columns are also lightweight and heat resistant, making them ideal for use in aerospace components, engines, and nuclear reactor parts. Engineers could use these microscopic structures as building blocks for macroscopic materials, says Julia R. Greer, a materials scientist at the California Institute of Technology. With the pillars’ unique combination of properties, “you could build robust parts for any extreme thermal mechanical environment,” she says. The words strong and rubbery do not typically go together for materials. Strong materials are usually hard, while elastic materials that can recover their original shape after being deformed are pliable. Combining ...

Bioinspired Carbon Quantum Dots: An Antibiofilm Agents.

Carbon dots, very tiny carbon material with various surface passivations, have emerged as a new class of nanomaterials for various applications. Herein, we describe a simple, economical, and green approach for the synthesis of colloidal luminescent carbon dots (C-dots) by solvothermal method from fruit juice of Citrus limetta, an abundantly available plant in Asian countries. The existence of C-dots was confirmed by X-ray Diffraction and High Resolution Transmission Electron Microscopy studies. The C-dots size was observed to be 2-4 nm. We further evaluated the efficacy of C-dots to inhibit the attachment of Candida albicans MTCC 227, and biofilm formation on the polystyrene surfaces. The C-dots have effectively inhibited the attachment and formation of biofilm in Candida albicans at very low concentrations, which is hitherto unattempted. The ability of C-dots to inhibit biofilm formation may contribute to diverse applications of C-dots in biomedical field.

Synthesis of tiny carbon dots with high quantum yield using multi-walled carbon nanotubes as support for selective “turn-off-on” detection of rutin and Al3+

The solid-phase pyrolysis method is widely used in the synthesis of fluorescent carbon dots (CDs) because of its large scale and solvent-saving advantages. However, CDs are inclined to agglomerate during the synthesis process, resulting in low quantum yield (QY) and inhomogeneous distribution of particle sizes. Here, a simple and effective solid dispersion surface pyrolysis method was used for the synthesis of tiny-carbon dots (T-CDs) with a high QY. Multi-walled carbon nanotubes (MWCNTs) were used as a support and 2-(N-morpholino)ethanesulfonic acid (MES) as a precursor. MES was uniformly dispersed on the surface of MWCNTs by hydrogen bonding and π-π interactions. Due to the excellent thermal conductivity and rigidity of MWCNTs, the precursor is carbonized without agglomeration. Compared with the CDs obtained by the direct pyrolysis method without the use of a solid support, the particle size of the T-CDs is small (0.69 ± 0.14 nm) and the QY increased from 17.8 to 42.8%. It is anticipated that this method will lead to the improvement of the QY of CDs. Applications of the T-CDs included fluorescence detection of rutin in pharmaceuticals, human urine, and human serum samples, and determination of Al3+ in tap water samples.

In situ synthesis of carbon doped porous silicon nanocomposites as high-performance anodes for lithium-ion batteries

We demonstrate the in situ synthesis of carbon doped porous silicon (Si/C) nanocomposites by a simple thermal displacement process between Mg2Si and inorganic gas CO2 in one-step. Via the decomposition of Mg2Si, the reduction process occurred between Mg and CO2, leading the uniform doping of many distributed tiny carbon nanoparticles into Si. Meanwhile, the porous structure was formed after an acid treatment. When worked as anodes for lithium-ion batteries, the as-prepared s-porous Si/C nanocomposites exhibited good cycling stability and high-rate capability, which were superior to the porous Si and porous Si/C nanocomposites. It was revealed that the enhanced electrochemical properties could be ascribed to the novel porous structure and doped carbon nanoparticles that can buffer the volume expansion, as well as enhance the electronic conductivity of Si. The reaction mechanism was well investigated by studying the influence of reaction temperature and raw Mg2Si particle size on the morphology and component of the porous Si/C nanocomposites.

Adsorption of Monocyclic Carbon Rings on Graphene: Energetics Revealed via Continuum Modeling.

Gas-phase spectroscopic detection of tiny carbon clusters is a recent success story in the area of carbon cluster research. However, experimental production and isolation of these clusters are extremely difficult because of their high reactivity. One possibility to isolate the generated clusters would be to deposit them on graphene and to desorb them for subsequent use. One of the pertinent questions toward realizing this would be the energetics of the adsorption process. Therefore, in this work, the energetics for the adsorption of the monocyclic carbon rings (Cn with n = 10, 12, 14, 16, 18, 20, and 22) on a graphene sheet are investigated using the analytical approaches, developed earlier by Hill and co-workers. The adsorption process here is driven by the noncovalent interactions between the carbon rings and the graphene sheet. The analyses of the interaction energies as a function of both the vertical distance Z and the rotational angle ϕ are performed in order to determine the preferred orientations, equilibrium positions, and binding energies for the adsorption of various carbon rings on graphene. We find that the preferred orientation of the rings with respect to the graphene sheet is the parallel orientation. The results from continuum, discrete–continuum, and discrete models are in good agreement. Further, computations using density functional theory and quantum mechanics/molecular mechanics approaches are performed, and comparisons of the computed energetics with the data from the models are reported. Finally, we highlight the scope and the limitations of the analytical models.

Biocompatible Carbon Nanodots for Functional Imaging and Cancer Therapy

This article describes how carbon quantum dots (C-dots) are tiny carbon nanoparticles (less than 10 nm in size) being envisaged to be used in bio-sensing, bio-imaging and drug delivery nanosystems. Their low toxicity and stable chemical properties make them suitable candidates for new types of fluorescent probe, which overcome the common drawbacks of previous fluorescent probes (organic dyes and inorganic quantum dots). In addition, fluorescent C-dots possess a rather strong ability to bind with other organic and inorganic molecules due to their abundant surface groups. For that reason, fluorescent C-dots can be manipulated via series of controllable chemical treatments in order to satisfy the demands in the photocatalytic, biochemical and chemical sensing, bio-imaging, drug delivery and enhanced cell targeting. In recent studies it was described the development of carbon quantum dots with large two-photon absorption cross sections towards two-photon imaging for use in photodynamic cancer therapy. Thus, C-dots have become a rising star in biomedical research with a promising future for the application in nanomedicine.

RETRACTED: Origin and transformation of organic carbon from the Hiawatha meteorite crater, North-West Greenland: a preliminary study

Glaciofluvial sand draining the newly discovered Hiawatha impact crater under the Greenland Ice Sheet in North-West Greenland contains shocked quartz, glasses derived from direct mineral melts, carbon-bearing glasses, particles of charcoal and transformed ('glassy') charcoal, as well as low-reflectance carbonaceous grains with tiny carbon spherules and mineral fragments. Some of these grains are interpreted as ejecta and perhaps plume material containing sublimated and re-deposited carbon. The only plausible carbon source of this carbon is subfossil Arctic vegetation including small conifer and angiosperm trees older than 50 ka and likely around 2.3 Ma in age, supporting a very young age of the crater.

High-Level Heteroatom Doped Two-Dimensional Carbon Architectures for Highly Efficient Lithium-Ion Storage.

In this work, high-level heteroatom doped two-dimensional hierarchical carbon architectures (H-2D-HCA) are developed for highly efficient Li-ion storage applications. The achieved H-2D-HCA possesses a hierarchical 2D morphology consisting of tiny carbon nanosheets vertically grown on carbon nanoplates and containing a hierarchical porosity with multiscale pore size. More importantly, the H-2D-HCA shows abundant heteroatom functionality, with sulfur (S) doping of 0.9% and nitrogen (N) doping of as high as 15.5%, in which the electrochemically active N accounts for 84% of total N heteroatoms. In addition, the H-2D-HCA also has an expanded interlayer distance of 0.368 nm. When used as lithium-ion battery anodes, it shows excellent Li-ion storage performance. Even at a high current density of 5 A g−1, it still delivers a high discharge capacity of 329 mA h g−1 after 1,000 cycles. First principle calculations verifies that such unique microstructure characteristics and high-level heteroatom doping nature can enhance Li adsorption stability, electronic conductivity and Li diffusion mobility of carbon nanomaterials. Therefore, the H-2D-HCA could be promising candidates for next-generation LIB anodes.

Microwave synthesis of titanium-containing carbon nanosheet over mesostructured cellular foam and the catalytic application

Titanium-containing carbon nanosheets have been prepared from graphite powder, titanocene dichloride, pyrrole and other components by using mesostructured cellular foam (MCF) as template under microwave irradiation. Characterizations reveal the present nanosheets have similar composition, functional group and thickness as classical graphene oxide, but they are probably formed by stitching of tiny carbon fibers those grown from pores of MCF. Meanwhile, titanium oxides appear on nanosheets, making a new catalytic system. In oxidation of alkenes, synthetic materials provide satisfactory conversions and promising stereoselectivities. Moreover, various oxidized products are obtained as key intermediates for synthesis of high-value-added chemicals. On the other hand, encouraging conversions and chiral inductions are realized in diethylzinc addition to benzaldehyde. Catalytic results also propose the synergy of MCF with attached chiral additive in chiral induction. This work not only provides a new method to produce two-dimensional carbon materials, but also shows their potentials for catalytic transformation of hydrocarbons, which would contribute to the design of new heterogeneous catalysts.

Mechanism of water transport in graphene oxide laminates

It is understood that nano-channels of graphene oxide membranes have a water flow mechanism which is similar to the water flow inside carbon nanotube pores. The water transport mechanisms recently proposed by various researchers suggest that membranes composed of graphene oxide laminates could be regarded as an assembly of many tiny carbon nanotubes stacked together with attached functional groups as spacers.

Fluorescent carbon nanodots for targeted in vitro cancer cell imaging

Carbon quantum dots (CQDs or C-dots, ≤10nm in size) are tiny carbon nanoparticles being envisaged in biosensing, bio-imaging and biomolecular/drug delivery. In the present investigation, green fluorescent carbon quantum/nano dots (GCQDs, ∼3nm in size) were synthesized through facile chemical slicing method. Further, folic acid (FA) functionalized GCQDs (GCQDs-FA) were obtained to enhance their targeting ability. FA is known to positively influence the binding potential and penetration into the cancer cells because of high abundance of folate receptors (FR) on various cancer cell membranes. We report high biocompatibility, photoluminescence stability and excellent in vitro cancer cell cytoplasm and nucleus targeting performance of GCQDs-FA on MCF-7 breast cancer cells.