Carbon Nanoforms Research Articles

Dialysis nanocomposite membranes based on carbon nanoforms inhibiting blood plasma protein adsorption.

Protein adsorption on medical devices in contact with blood is a significant issue during renal replacement therapy. Main forces determining fouling are the electrostatic interactions between membrane and charged protein, but the dialysis membrane surface charges can be adjusted by modifying the polymer matrix to decrease the blood plasma protein adsorption. In this study, polysulfone membranes (PSU) were modified by incorporation of carbon nanoparticles such as: multiwall carbon nanotubes (2 wt.% MWCNT), graphene oxide (1 wt.% GO), and graphite (5 wt.% GR) during manufacturing process (nonsolvent-induced phase separation, NIPS). The PSU flat sheet membrane was the reference sample. Observed morphology of nanocomposite membranes was similar (SEM imaging); all of them had finger-like pore structure with unimodal distribution of pore size and similar skin-to-support ratio (1:3). The carbon nanoadditives also influenced the surface wettability: hydrophobicity and surface free energy of membranes increased (polar components of energy were reduced, while the dispersive components were increased). The surface charge of nanocomposite membranes increased, when the polymer matrix has been modified with CNT or GR. This significantly affects the adsorption of proteins such as chicken (CSA) and bovine serum albumin (BSA) and reduces blood clotting on the membrane.

Carbon and graphene based nanocomposites for gas sensors—Current state and advances

After the discovery of carbon nanoforms, carbon nanotube (one dimensional) and tube like nanostructure and graphene (two dimensional) nanosheets have gained immense research curiosity. Further nanotechnological developments have moved towards the formation of carbon nanotube nanocomposites and graphene nanocomposites. For the purpose, various matrices including thermoplastic polymers and conjugated polymers have been used. Methodology is the systematic gathering of the literature and development of a novel review outline, theme, and discussions regarding the discussed topics. Hence, varying conjugated polymers such as polyaniline, polythiophene, poly(3,4-ethylenedioxythiophene), and nonconjugated nylon, poly(ethylene glycol), etc. have been processed using techniques like in situ, solution, electropolymerization, spin coating, etc. In sensors, the nanocomposites need to develop fine nanoparticle dispersion, network formation, and interfacial interactions ultimately supporting the electron or charge transfer in these nanomaterials desirable for the recognition of the gaseous species. Moreover, interactions of the nanocomposite with the analyte molecules define the sensing capabilities of the nanomaterials. Consequently, nanocarbon nanocomposite based gas sensors have been analyzed for conductivity, change in resistance, sensitivity, selectivity, response time, detection limit, and other desirable properties. For future designs, it is recommended to develop high-tech combinations of conjugated polymers like polythiophene derivatives using functional forms of graphene and carbon nanotube. In addition, use of advanced manufacturing techniques like 3D/4D printing and spin coating must be applied to form efficient sensors. In conclusions, this manuscript presents not only comprehensive but also comparative analysis on different gas analysis parameters such as detection limit, concentration, response time, etc. for various nanocomposite sensors. Lastly, the encounters in preparing and applying graphene/carbon nanotube sensors, associated utilizations, and possible future prospects have been discussed.

Fluorescent Nanocarbons: From Synthesis and Structure to Cancer Imaging and Therapy.

Nanocarbons are emerging at the forefront of nanoscience, with diverse carbon nanoforms emerging over the past two decades. Early cancer diagnosis and therapy, driven by advanced chemistry techniques, play a pivotal role in mitigating mortality rates associated with cancer. Nanocarbons, with an attractive combination of well-defined architectures, biocompatibility, and nanoscale dimension, offer an incredibly versatile platform for cancer imaging and therapy. This paper aims to review the underlying principles regarding the controllable synthesis, fluorescence origins, cellular toxicity, and surface functionalization routes of several classes of nanocarbons: carbon nanodots, nanodiamonds, carbon nanoonions, and carbon nanohorns. This review also highlights recent breakthroughs regarding the green synthesis of different nanocarbons from renewable sources. It also presents a comprehensive and unified overview of the latest cancer-related applications of nanocarbons and how they can be designed to interface with biological systems and work as cancer diagnostics and therapeutic tools. The commercial status for large-scale manufacturing of nanocarbons is also presented. Finally, it proposes future research opportunities aimed at engendering modifiable and high-performance nanocarbons for emerging applications across medical industries. This work is envisioned as a cornerstone to guide interdisciplinary teams in crafting fluorescent nanocarbons with tailored attributes that can revolutionize cancer diagnostics and therapy.

Nanotube-Like Electronic States in [5,5]-C90 Fullertube Molecules.

Fullertubes, that is, fullerenes consisting of a carbon nanotube moiety capped by hemifullerene ends, are emerging carbon nanomaterials whose properties show both fullerene and carbon nanotube (CNT) traits. Albeit it may be expected that their electronic states show a certain resemblance to those of the extended nanotube, such a correlation has not yet been found or described. Here it shows a scanning tunneling microscopy (STM) and spectroscopy (STS) characterization of the adsorption, self-assembly, and electronic structure of 2D arrays of [5,5]-C90 fullertube molecules on two different noble metal surfaces, Ag(111) and Au(111). The results demonstrate that the shape of the molecular orbitals of the adsorbed fullertubes corresponds closely to those expected for isolated species on the grounds of density functional theory calculations. Moreover, a comparison between the electronic density profiles in the bands of the extended [5,5]-CNT and in the molecules reveals that some of the frontier orbitals of the fullertube molecules can be described as the result of the quantum confinement imposed by the hemifullerene caps to the delocalized band states in the extended CNT. The results thus provide a conceptual framework for the rational design of custom fullertube molecules and can potentially become a cornerstone in the understanding of these new carbon nanoforms.

Overview of Engineering Carbon Nanomaterials Such As Carbon Nanotubes (CNTs), Carbon Nanofibers (CNFs), Graphene and Nanodiamonds and Other Carbon Allotropes inside Porous Anodic Alumina (PAA) Templates

The fabrication and design of carbon-based hierarchical structures with tailored nano-architectures have attracted the enormous attention of the materials science community due to their exceptional chemical and physical properties. The collective control of nano-objects, in terms of their dimensionality, orientation and size, is of paramount importance to expand the implementation of carbon nanomaterials across a large variety of applications. In this context, porous anodic alumina (PAA) has become an attractive template where the pore morphologies can be straightforwardly modulated. The synthesis of diverse carbon nanomaterials can be performed using PAA templates, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds, or can act as support for other carbon allotropes such as graphene and other carbon nanoforms. However, the successful growth of carbon nanomaterials within ordered PAA templates typically requires a series of stages involving the template fabrication, nanostructure growth and finally an etching or electrode metallization steps, which all encounter different challenges towards a nanodevice fabrication. The present review article describes the advantages and challenges associated with the fabrication of carbon materials in PAA based materials and aims to give a renewed momentum to this topic within the materials science community by providing an exhaustive overview of the current synthesis approaches and the most relevant applications based on PAA/Carbon nanostructures materials. Finally, the perspective and opportunities in the field are presented.

L-Cysteine Modified Chitosan Nanoparticles and Carbon-Based Nanostructures for the Intranasal Delivery of Galantamine.

The present study evaluates the use of thiolized chitosan conjugates (CS) in combination with two fundamental carbon nanoforms (carbon dots (CDs) and Hierarchical Porous Carbons (HPC)) for the preparation of intranasally (IN) administrated galantamine (GAL) nanoparticles (NPs). Initially, the modification of CS with L-cysteine (Cys) was performed, and the successful formation of a Cys-CS conjugates was verified via 1H-NMR, FTIR, and pXRD. The new Cys-CS conjugate showed a significant solubility enhancement in neutral and alkaline pH, improving CS’s utility as a matrix-carrier for IN drug administration. In a further step, drug-loaded NPs were prepared via solid-oil–water double emulsification, and thoroughly analyzed by SEM, DLS, FTIR and pXRD. The results showed the formation of spherical NPs with a smooth surface, while the drug was amorphously dispersed within most of the prepared NPs, with the exemption of those systems contianing the CDs. Finally, in vitro dissolution release studies revealed that the prepared NPs could prolong GAL’s release for up to 12 days. In sum, regarding the most promising system, the results of the present study clearly suggest that the preparation of NPs using both Cys-CS and CDs results in a more thermodynamically stable drug dispersion, while a zero-order release profile was achieved, which is essential to attain a stable in vivo pharmacokinetic behavior.

Burn Them Right! Determining the Optimal Temperature for the Purification of Carbon Materials by Combustion

A new purification procedure for carbon nanoforms is proposed. It was tested on multiwall carbon nanotubes (MWCNTs) prepared by arc discharge, which is among the most challenging of cases due to the chemical and structural similarity between the MWCNTs and most of the impurities to be removed. Indeed, the various methods for synthesizing carbon nanoforms lead to a distribution of carbonaceous products, such as carbon shells, carbon spheres, fullerenes, and a variety of other species. Thus, many strategies to purify the desired products have been developed. Among the most successful ones, thermal oxidation (combustion) seems particularly efficient. To be successful while preserving a reasonable amount of MWCNTs, the combustion temperature has to be carefully selected. Moreover, the ideal combustion temperature does not only depend on the material to be treated but also on the overall system used to perform the reaction, including the reactor type and the parameters of the gaseous reactant. Typically, the optimization of the purification relies on multiple experiments and analysis of the products. However, to the best of our knowledge, a strategy to determine a priori the most suitable temperature has not been reported yet. We demonstrate here that a thermogravimetric method, namely the constant decomposition rate thermal analysis (CRTA), is particularly well adapted to answer this question. An isothermal treatment based on the results obtained from a CRTA program allowed arc-MWCNTs to be successfully purified from graphenic shells while optimizing the yield of the MWCNTs. This strategy is believed to be valuable not only for purifying MWCNTs but also for the purification of other carbonaceous forms, including new carbon nanoforms.

Efficient and Stable Perovskite Solar Cells based on Nitrogen-Doped Carbon Nanodots.

The role of graphitic and amorphous nitrogen‐doped carbon dots (N‐CDs) as additives for perovskite solar cells (PSCs) is investigated. A detailed study of N‐CDs: perovskite (PVSK) blends through X‐ray diffraction, nuclear magnetic resonance, field emission scanning electron microscopy, UV–vis, and photoluminescence spectroscopy reveals the existence of interactions between N‐CDs and PVSK. The amorphous or graphitic nature of these carbon nanoforms, as well as the interactions between CDs and PVSK, clearly determines the photovoltaic outcome of the PSCs. Thus, a small amount of graphitic carbon dots (g‐N‐CDs) leads to more‐stable PSCs, while maintaining and even improving the power conversion efficiency (PCE). In addition, the long‐term evaluation of the g‐N‐CDs‐containing cells shows improvement of the PCE over time, up to 109% of the initial efficiency after 40 days while the reference performance is dropped to 86%.

Corrosion Resistance and Electrical Conductivity of Hybrid Coatings Obtained from Polysiloxane and Carbon Nanotubes by Electrophoretic Co-Deposition.

Nanocomposites developed based on siloxanes modified with carbon nanoforms are materials with great application potential in the electronics industry, medicine and environmental protection. This follows from the fact that such nanocomposites can be endowed with biocompatibility characteristics, electric conductivity and a high mechanical durability. Moreover, their surface, depending on the type and the amount of carbon nanoparticles, may exhibit antifouling properties, as well as those that limit bacterial adhesion. The paper reports on the properties of polysiloxane (PS) and carbon nanotubes (CNT) nanocomposite coatings on metal surfaces produced by the electrophoretic deposition (EPD). A comparison with coatings made of pure PS or pure CNT on the same substrates using the same deposition method (EPD) is provided. The coatings were examined for morphology and elemental composition (SEM, EDS), structural characteristics (confocal Raman spectroscopy), electrical conductivity and were tested for corrosion (electrochemical impedance spectroscopy-EIS, potentiodynamic polarization-PDP). The results obtained in this study clearly evidenced that such hybrid coatings conduct electricity and protect the metal from corrosion. However, their corrosion resistance differs slightly from that of a pure polymeric coating.

Advances in micro‐supercapacitors (MSCs) with high energy density and fast charge‐discharge capabilities for flexible bioelectronic devices—A review

AbstractSupercapacitors are a new brand of high‐performance nanoengineered devices that match the high capacity of batteries for electric energy storage with the ability of dry capacitors for ultra‐fast charging or discharging rates. Thus, supercapacitors are capable of simultaneously providing the high energy‐density and high power‐density, demanded in a plethora of biosensors and portable electronic devices. In this review, a variety of nanomaterials investigated for possible applications in novel supercapacitors have been evaluated including different carbon nanoforms, metal oxides or hydroxides, chalcogenides, carbides and phosphates, as well as organic redox species, conductive polymers, metal‐organic frameworks, MXenes and others. Different strategies for boosting volumetric capacitance, power density and charge or discharge cycling stability of micro‐supercapacitors (MSCs) designed from these materials have been reviewed and their application potential assessed. Special attention has been given to micro‐supercapacitor's designs that are suitable for miniaturization and integration with flexible microcircuits for wearable and implantable biomedical devices, remotely rechargeable sensors, microprocessor‐controlled data processing chips, biomorphic computing, smart phone communication, military, automotive applications and emerging technologies. The different strategies applied for MSCs design and fabrication, including femto‐laser writing, photolithography, screen printing, stamping, inkjet printing, mask patterning and others, have been assessed. The exciting future perspectives of MSCs have been discussed.

Recent Advances on Multivalent Carbon Nanoform-Based Glycoconjugates

Multivalent carbohydrate-mediated interactions are key to many biological processes including disease mechanisms. In order to study these important glycan-mediated interactions at a molecular level, carbon nanoforms such as fullerenes, carbon nanotubes or graphene and their derivatives have been identified as promising biocompatible scaffolds that can mimic the multivalent presentation of biologically relevant glycans. In this mini-review, we will summarize the most relevant examples of the last few years in the context of their applications.

Nonpolar Graphene Quantum Dot-Based Hydrophobic Coating from Microwave-Assisted Treatment of Styrofoam Waste

Graphene quantum dots (GQDs), one of the most promising nanoforms of carbon, have shown exceptional physiochemical properties owing to their strong three-dimensional quantum confinement. By altering the band gap or edge functionalization in GQDs, the properties can be tuned to meet challenging demands of modern computational and quantum devices. GQDs have primarily been synthesized at the lab scale so far, by both top-down and bottom-up approaches, using various natural or synthetic carbon-rich precursors. Only a few milligrams of the precursor is typically used in the synthesis, and it also involves hazardous acids, bases, or other catalysts, which impose additional time, labor, and cost for their removal. GQDs made hitherto are also functionalized with polar moieties due to the use of acids or bases in the synthesis, resulting in insolubility of GQDs in nonpolar solvents. Herein, an acid/base-free, microwave-assisted pyrolytic process is developed where GQDs of controlled size without any polar functionalities are synthesized using Styrofoam waste as the precursor. The structure of GQDs is confirmed by transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and other spectroscopic analysis, and it is found to be single layered with an average size of 5.5 ± 1.5 nm. A maximum yield of 15% is obtained by optimizing the pyrolysis temperature and exposure time of the precursor, and GQDs are found to be highly soluble in nonpolar solvents, including toluene and cyclohexane. The obtained GQDs were used as a promising agent to provide durable hydrophobicity and excellent self-cleaning property when coated on cotton fabric. The use of nonbiodegradable polymer waste such as Styrofoam to generate nonpolar GQDs of controlled dimensions provided a complete solution to not only curb deleterious effects of polymeric waste but also enable production of high value-added products for vast applications.

In Ukrainian

The aim of the study was to investigate the effect of heteroatoms on the deformation of graphene, as well as on the formation of the Stone-Wallace defect. To date, research on processes involving nanocarbon materials is relevant. In particular, in the formation of fullerenes, nanoonions and a number of other carbon nanoforms, the five-membered carbon cycles (pentactagonis) of the hepatogenesis (pentactagon) play the most important role in the curvature of initially flat graphene sheets and the formation of fullerene-like structures in the form of closed, skeletal, macromolecular formations. It should be noted, however, that the Pentagon is not the only factor in distorting the flat structure of graphene sheets in layered carbon materials. Some other defects of the carbon lattice (in particular, seven-membered carbon cycles and heteroatoms of a number of nonmetals with covalent radii exceeding the radius of the carbon atom) may play a similar role to one degree or another. These heteroatoms (primarily Si, P, S) are usually part of the precursors of mineral or vegetable origin and can be embedded in the carbon lattice in the process of coal production. Stone-Wallace there is their mutual compensation and preservation of a flat structure. The calculations were performed using quantum chemical modeling of doped nanographs in clusters of different size, composition and morphology, using the theory of density functional (DFT) with exchange-correlation functional B3LYP, based on the extended valence-split basis 6-31G (d) with full optimism clusters using the Firefly software package. It has been found that heteroatoms of non-metals with covalent radii exceeding the radius of the C atom, which are usually present in the precursors of mineral or vegetable origin used to produce pyrolyzed carbon materials, can play a significant role in energy. a number of nanoforms of carbon, activated carbon and other pyrolyzed nanostructured carbon materials.

A Study on the Stability of Carbon Nanoforms-Polyimidazolium Network Hybrids in the Conversion of CO2 into Cyclic Carbonates: Increase in Catalytic Activity after Reuse.

Three different carbon nanoforms (CNFs), single-walled and multi-walled carbon nanotubes (SWCNTs, MWCNTs) and carbon nanohorns (CNHs), have been used as supports for the direct polymerization of variable amounts of a bis-vinylimidazolium salt. Transmission electron microscopy confirmed that all CNFs act as templates on the growth of the polymeric network, which perfectly covers the nanocarbons forming a cylindrical (SWCNTs, MWCNTs) or spherical (CNHs) coating. The stability of these hybrid materials was investigated in the conversion of CO2 into cyclic carbonate under high temperature and CO2 pressure. Compared with the homopolymerized monomer, nanotube-based materials display an improved catalytic activity. Beside the low catalytic loading (0.05–0.09 mol%) and the absence of Lewis acid co-catalysts, all the materials showed high TON values (up to 1154 for epichlorohydrin with SW-1:2). Interestingly, despite the loss of part of the polymeric coating for crumbling or peeling, the activity increases upon recycling of the materials, and this behaviour was ascribed to their change in morphology, which led to materials with higher surface areas and with more accessible catalytic sites. Transmission electron microscopy analysis, along with different experiments, have been carried out in order to elucidate these findings.

Theoretical Insights for Materials Properties of Cyclic Organic Nanorings

AbstractThe synthesis of new carbon nanoforms with remarkable and fine‐tuned bulk properties still represents a formidable challenge, with cyclic organic nanorings emerging in recent years for the template‐driven design of this kind of systems. The design and engineering of these materials can be first controlled at the molecular scale, to further induce their specific self‐assembly toward tailored properties at the nanoscale. Theoretical studies have lately contributed to the understanding of the underlying physical effects, the development of synthetic strategies, and the rationalization of novel materials properties, employing a variety of methods ranging from accurate calculations of isolated molecules to atomistic molecular dynamics simulations of a large sample of molecules in realistic conditions, which will be reviewed here with a focus on the transition from single‐molecule to supramolecular properties.

Thermokinetic Model for the Formation and Oxidation of Carbon Nanoforms

A thermokinetic model for the formation and decomposition of layered carbon nanoforms (LCNFs) has been proposed. The model relies on the fundamental dependence of discrete temperature component in the CO (Boudouard–Meyer) disproportionation reaction. Reversible reduction–oxidation reactions for individual LCNFs superpose in the range 820–1070 K. The superposition of reaction package has two thermokinetic components: rapid (discrete) and slow (continuous). The rate vred/ox C of the continuous process is 10–8–10–7 mole/sec. The activation parameter Ea ox C of the first-order reaction (smoldering) has been determined as 35 ± 5 kJ/mole. The rate of rapid oxidation processes exponentially depends on temperature, and vred/ox C is 10–6–10–5 mole/sec in the range 1073–1473 K. The activation energies for oxidation (combustion) of most nanoforms are in the range ~173 ± 5 kJ/mole. The oxidation temperatures for carbon nanoforms have been found. The following carbon nanoforms are mainly synthesized or oxidized in a CO or oxygen atmosphere: nanoonions at 823 K, graphite nanoplatelets at 873 K, stacked nanofibers at 923 K, conical nanofibers at 973 K, coiled nanofibers at 1013 K, multiwall nanotubes at 1033 K, and single-wall nanotubes at 1173 K. Carbon polymerization is driven by free radicals. The polymerization is catalytically promoted by three types of primary paramagnetic carbon radicals with one to three free electrons. The concentrations of radicals represent superposed Gaussian curves on the promoter’s acceptor surface in the range 820–1070 K. Primary radicals give rise to three nanoforms: spherical, lamellar, and tubular. The reactions are reversible as a function of environment and temperature. When equilibrium precipitation of the LCNFs and ‘carbon sludge’ is achieved, the reaction package is eventually converted to a S-shaped curve similar to the temperature dependence of CO partial pressure. The chemical properties of nanoforms combine two topological interactions: peripheral hydrophilic and surface hydrophobic. The synthesis and up-stop-up oxidation procedures in the qualification and selective determination of carbon nanoforms in mixtures are discussed.

Evaluation of Possible Isotopic Effects for Cavitational Carbon Nanoforms

Possible processes of the carbon isotopes fraction under hydrodynamic caviation at carbon-containing liquids are considered. We have made corresponding experiments with benzene, toluene and ethanol to provide carbon nanoforms with different crystal structures. Specific bonding forces for metals and n-diamond are modeled using developed numerical method. The task is to identify the key parameters affecting the pairs force potentials of carbon atoms and consider the application of the results to microelectronics and natural processes.

New Molecular Chemosensors Based on Niobium(V) 5,10,15,20-(Tetra-4-tert-butylphenyl)porphine for Detection of VOCs

Reactions of pyridine (Py) with (5,10,15,20-(tetra-4-tert-butylphenyl)porphinato)trichloroniobium(V) (Nb(Cl)3TtBuPP) and H+-bonded Nb(Cl)3TtBuPP (Nb(Cl)3TtBuPP···H+···Cl−) in toluene have been studied using spectroscopy (UV-vis, IR, 1H NMR, mass spectrometry, fluorescence), thermodynamics and kinetics. The process is a system of consecutive two- and one-way reactions of the two pyridine molecules bonding; the nature of this interactions is determined by the chemical structure of the initial niobium(V) porphyrin. The reactions have been completely quantitatively described, and the intermediate and final products spectral parameters used for the product chemical structure confirmation have been determined. It has been demonstrated that Nb(Cl)3TtBuPP and Nb(Cl)3TtBuPP···H+···Cl− are good candidates for use as optical and fluorescent chemosensors of VOCs (volatile organic compounds) and nitrogenous bases—building blocks of pharmaceuticals, food components, and environmental pollutants—with the following parameters: the stability constant of the complex with pyridine K = (1.99 ± 0.3) × 104 L2/mol2 and (2.8 ± 0.5) × 102 L/mol, relative optical response A = 0.91 and 0.35, detection limit of Py 1.74 × 10–3 and 4.05 × 10–4 mol/L, respectively. The results are applicable for use in the design of dye-sensitized solar cells (DSSCs) since the reaction studied is a model for self-assembly of donor–acceptor systems based on metalloprorphyrins and pyridyl derivatives of carbon nanoforms.

Chiral Molecular Carbon Nanostructures

Chirality is a fascinating property present in naturally occurring and artificial molecules and materials, observable as chiroptical behavior. The emerging area of carbon nanostructures has undergone tremendous development, with a wide variety of carbon nanoforms reported over the last two decades. However, despite interest in merging chirality and nanocarbons, this has been successfully achieved only in empty fullerenes, whereas in other kinds of fullerenes or carbon nanostructures such as carbon nanotubes, graphene, and graphene quantum dots (GQDs), to name the most popular systems, it is almost unknown. Therefore, controlling chirality in carbon nanostructures currently represents a major challenge for the chemical community. In this Account, we show our progress in the synthesis of chiral molecular carbon nanostructures, namely, metallofullerenes, endohedral fullerenes, GQDs, and curved molecular nanographenes, by using asymmetric catalysis and both top-down and bottom-up chemical approaches. Furthermore, we bring in a new family of lesser-known molecular chiral bilayer nanographenes, where chirality is introduced from the starting helicene moiety and a single enantiomer of the nanographene is synthesized. Some important landmarks in the development of chiral molecular carbon nanostructures shown in this Account are the application of synthesis-tailored, enantiomerically pure metallofullerenes as catalysts for hydrogen transfer reactions and the use of endohedral fullerenes to determine the effect of the incarcerated molecule in the carbon cage on the cis-trans stereoisomerization of optically active pendent moieties. Furthermore, the first top-down synthesis of chiral GQDs by functionalization with chiral alcohols is also presented. An emerging alternative to GQDs, when the desire for purity and atomistic control outweighs the cost of multistep synthesis, is the bottom-up approach, in which molecular nanographenes are formed in precise sizes and shapes and enantiomeric control is feasible. In this regard, a singular and amazing example is given by our synthesis of a single enantiomer of the first chiral bilayer nanographene, which formally represents a new family of molecular nanographenes with chirality controlled and maintained throughout their syntheses. The aforementioned synthetic chiral nanostructures represent groundbreaking nanocarbon systems where chirality is a further dimension of structural control, paving the way to a new scenario for carbon nanoforms in which chirality selection determines the properties of these novel carbon-based materials. Fine-tuning of such properties is envisioned to impact biomedical and materials science applications.

Templating effect of carbon nanoforms on highly cross‐linked imidazolium network: Catalytic activity of the resulting hybrids with Pd nanoparticles

Two different carbon nanoforms (CNFs), namely multi‐walled carbon nanotubes (MWCNTs) and carbon nanohorns (CNHs), have been chosen as support for the direct polymerization of a bis‐vinylimidazolium salt. Transmission electron microscopy analyses revealed a templating effect of the CNFs on the growth of the polymeric network, which perfectly covers their whole surfaces creating a cylindrical or spherical coating for MWCNTs and CNHs, respectively. Subsequently, the CNFs‐polyimidazolium have been used as stabilizers for Pd nanoparticles (Pd NPs), and the obtained materials have been characterized by means of analytical and spectroscopic techniques and then employed as easily recoverable and recyclable catalysts for Suzuki and Heck reactions. Quantitative conversions have been obtained in almost all the explored reactions, even employing low loading of catalyst (down to 0.007 mol%). Suzuki reactions were carried out in pure water under aerobic conditions. Both materials showed excellent activity and recyclability for the investigated C‐C coupling reactions, with the CNHs‐based material resulting slightly more active than the MWCNTs‐based one due to a higher superficial exposure of Pd NPs.