Hybrids of Fullerenes and 2D Nanomaterials

Simultaneously Producing H2 and H2O2 by Photocatalytic Water Splitting: Recent Progress and Future

The solar-driven overall water splitting (2H2O→2H2 + O2) is considered as one of the most promising strategies for reducing carbon emissions and meeting energy demands. However, due to the sluggish performance and high H2 cost, there is still a big gap for the current photocatalytic systems to meet the requirements for practical sustainable H2 production. Economic feasibility can be attained through simultaneously generating products of greater value than O2, such as hydrogen peroxide (H2O2, 2H2O→H2 + H2O2). Compared with overall water splitting, this approach is more kinetically feasible and generates more high-value products of H2 and H2O2. In several years, there has been an increasing surge in exploring the possibility and substantial progress has been achieved. In this review, a concise overview of the importance and underlying principles of PIWS is first provided. Next, the reported typical photocatalysts for PIWS are discussed, including commonly used semiconductors and cocatalysts, essential design features of these photocatalysts, and connections between their structures and activities, as well as the selected approaches for enhancing their stability. Then, the techniques used to quantify H2O2 and the operando characterization techniques that can be employed to gain a thorough understanding of the reaction mechanisms are summarized. Finally, the current existing challenges and the direction needing improvement are presented. This review aims to provide a thorough summary of the most recent research developments in PIWS and sets the stage for future advancements and discoveries in this emerging area.

Breaking barriers: Innovative approaches for skin delivery of RNA therapeutics

RNA therapeutics represent a rapidly expanding platform with game-changing prospects in personalized medicine. The disruptive potential of this technology will overhaul the standard of care with reference to both primary and specialty care. To date, RNA therapeutics have mostly been delivered parenterally via injection, but topical administration followed by intradermal or transdermal delivery represents an attractive method that is convenient to patients and minimally invasive. The skin barrier, particularly the lipid-rich stratum corneum, presents a significant hurdle to the uptake of large, charged oligonucleotide drugs. Therapeutic oligonucleotides need to be engineered for stability and specificity and formulated with state-of-the-art delivery strategies for efficient uptake. This review will cover various passive and active strategies deployed to enhance permeation through the stratum corneum and achieve effective delivery of RNA therapeutics to treat both local skin disorders and systemic diseases. Some strategies to achieve selectivity between local and systemic administration will also be discussed.

Synthesis of [60]Fullerene-Fused Lactones via Carboxylic Acid Group-Directed C-H Bond Activation and Further Retro Baeyer-Villiger Reaction

An efficient palladium-catalyzed reaction of [60]fullerene with benzoic acids via carboxylic acid group-directed C-H bond activation is achieved. The obtained [60]fullerene-fused lactones can undergo a retro Baeyer-Villiger reaction to provide [60]fullerene-fused ketones via apparent reduction in the presence of triflic acid. A representative ketone product obtained by the reduction reaction can be employed as an overcoating layer for the electron-transporting layer in an n-type perovskite solar cell.

Solution Dynamics of Covalent Open-[60]Fullerene Dimers

The translational diffusivity of covalent open-[60]fullerene dimers in an organic solvent was found to be well describable by a prolate ellipsoid model while a monomeric open-[60]fullerene behaves like a sphere model. The water association dynamics were examined for two open-[60]fullerene dimers, showing a higher water affinity for the sp3-linked dimer relative to sp2-linked dimer owing to an effective orbital-orbital overlap identified by π(fullerene)→σ*(H2O) interactions as suggested by theoretical calculations.

Sulfonate-modified fullerenes mimicking tentacle structures for humidity sensors

In this work, a straightforward method for synthesizing fullerene derivatives with tentacle structures has been explored for monitoring environmental humidity, which involves introducing sulfonate onto the fullerenes. The structure and number of polar groups in three fullerene derivatives determined by a series of structural tests greatly affect their hydrophilicity and morphology, resulting in changes in humidity sensitive properties. In particular, the hysteresis and response time of the sensors display a great correlation with hydrophilicity. C60-Ho, the best performing derivative of this work, has exhibited high response values (∼3500 times), good linearity (R2 = 97.3 %), and rapid response/recovery times (0.3/4.4 s), making it suitable for various applications such as non-contact detection of respiration, finger distance, and soil humidity.

Phosphine-Mediated Dimerization of Open-[60]Fullerenes

By a reaction of trimethylphosphine with an open-[60]fullerene, corresponding dimers could be generated via two-fold deoxygenation processes even though the formation of β-oxo-phosphorous ylide is inevitable, a part of which is hydrolyzed to yield an α-methylene carbonyl derivative. Nevertheless, Wittig reaction and aldol condensation did not proceed well, indicating the presence of an unknown dimerization pathway. In the ylide formation, 1-phosphonium-3-carbabetaine was previously proposed as a key intermediate. Upon assuming that the betaine also participates in the dimerization process, we examined a possible reaction pathway computationally. As the results, the betaine formed by a reaction with the first phosphine was suggested to undergo nucleophilic addition to an unreacted molecule of the open-[60]fullerene, yielding an epoxide dimer which is then deoxygenated by the second phosphine to furnish the desired open-[60]fullerene dimer.

CA19-9 and CEA biosensors in pancreatic cancer

Cancer is a complex pathophysiological condition causing millions of deaths each year. Early diagnosis is essential especially for pancreatic cancer. Existing diagnostic tools rely on circulating biomarkers such as Carbohydrate Antigen 19-9 (CA19-9) and Carcinoembryonic Antigen (CEA). Unfortunately, these markers are nonspecific and may be increased in a variety of disorders. Accordingly, diagnosis of pancreatic cancer generally involves more invasive approaches such as biopsy as well as imaging studies. Recent advances in biosensor technology have allowed the development of precise diagnostic tools having enhanced analytical sensitivity and specificity. Herein we examine these advances in the detection of cancer in general and in pancreatic cancer specifically. Furthermore, we highlight novel technologies in the measurement of CA19-9 and CEA and explore their future application in the early detection of pancreatic cancer.

Recent advances in supramolecular fullerene chemistry

Fullerene chemistry has come a long way since 1990, when the first bulk production of C60 was reported. In the past decade, progress in supramolecular chemistry has opened some remarkable and previously unexpected opportunities regarding the selective (multiple) functionalization of fullerenes and their (self)assembly into larger structures and frameworks. The purpose of this review article is to provide a comprehensive overview of these recent developments. We describe how macrocycles and cages that bind strongly to C60 can be used to block undesired addition patterns and thus allow the selective preparation of single-isomer addition products. We also discuss how the emergence of highly shape-persistent macrocycles has opened opportunities for the study of photoactive fullerene dyads and triads as well as the preparation of mechanically interlocked compounds. The preparation of two- or three-dimensional fullerene materials is another research area that has seen remarkable progress over the past few years. Due to the rapidly decreasing price of C60 and C70, we believe that these achievements will translate into all fields where fullerenes have traditionally (third-generation solar cells) and more recently been applied (catalysis, spintronics).

Dearomative Ring-Fused Azafulleroids and Carbazole-Derived Metallofullerenes: Reactivity Dictated by Encapsulation in a Fullerene Cage

Herein, we report divergent additions of 2,2'-diazidobiphenyls to C60 and Sc3 N@Ih -C80 . In stark contrast to that of the previously reported bis-azide additions, the unexpected cascade reaction leads to the dearomative formation of azafulleroids 2 fused with a 7-6-5-membered ring system in the case of C60 . In contrast, the corresponding reaction with Sc3 N@Ih -C80 switches to the C-H insertion pathway, thereby resulting in multiple isomers, including a carbazole-derived [6,6]-azametallofulleroid 3 and a [5,6]-azametallofulleroid 4 and an unusual 1,2,3,6-tetrahydropyrrolo[3,2-c]carbazole-derived metallofullerene 5, whose molecular structures have been unambiguously determined by single-crystal X-ray diffraction analyses. Among them, the addition type of 5 is observed for the first time in all reported additions of azides to fullerenes. Furthermore, unexpected isomerizations from 3 to 5 and from 4 to 5 have been discovered, providing the first examples of the isomerization of an azafulleroid to a carbazole-derived fullerene rather than an aziridinofullerene. In particular, the isomerism of the [5,6]-isomer 4 to the [5,6]-isomer 5 is unprecedented in fullerene chemistry, contradicting the present understanding that isomerization generally occurs between [5,6]- and [6,6]-isomers. Control experiments have been carried out to rationalize the reaction mechanism. Furthermore, representative azafulleroids have been applied in organic solar cells, thereby resulting in improved power conversion efficiencies.

Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization

Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.

Single-atomic platinum on fullerene C60 surfaces for accelerated alkaline hydrogen evolution

The electrocatalytic hydrogen evolution reaction (HER) is one of the most studied and promising processes for hydrogen fuel generation. Single-atom catalysts have been shown to exhibit ultra-high HER catalytic activity, but the harsh preparation conditions and the low single-atom loading hinder their practical applications. Furthermore, promoting hydrogen evolution reaction kinetics, especially in alkaline electrolytes, remains as an important challenge. Herein, Pt/C₆₀ catalysts with high-loading, high-dispersion single-atomic platinum anchored on C₆₀ are achieved through a room-temperature synthetic strategy. Pt/C₆₀-2 exhibits high HER catalytic performance with a low overpotential (η₁₀) of 25 mV at 10 mA cm^-2. Density functional theory calculations reveal that the Pt-C₆₀ polymeric structures in Pt/C₆₀-2 favors water adsorption, and the shell-like charge redistribution around the Pt-bonding region induced by the curved surfaces of two adjacent C₆₀ facilitates the desorption of hydrogen, thus favoring fast reaction kinetics for hydrogen evolution.

Enhanced Thermoelectricity in Metal-[60]Fullerene-Graphene Molecular Junctions

The thermoelectric properties of molecular junctions consisting of a metal Pt electrode contacting [60]fullerene derivatives covalently bound to a graphene electrode have been studied by using a conducting-probe atomic force microscope (c-AFM). The [60]fullerene derivatives are covalently linked to the graphene via two meta-connected phenyl rings, two para-connected phenyl rings, or a single phenyl ring. We find that the magnitude of the Seebeck coefficient is up to nine times larger than that of Au-C₆₀-Pt molecular junctions. Moreover, the sign of the thermopower can be either positive or negative depending on the details of the binding geometry and on the local value of the Fermi energy. Our results demonstrate the potential of using graphene electrodes for controlling and enhancing the thermoelectric properties of molecular junctions and confirm the outstanding performance of [60]fullerene derivatives.

[60]Fullerene-Fused Cyclopentanes: Mechanosynthesis and Photovoltaic Application

The mechanochemical cascade reaction of [60]fullerene with 3-benzylidene succinimides, diethyl 2-benzylidene succinate, or 2-benzylidene succinonitrile in the presence of an inorganic base has been investigated under solvent-free and ball-milling conditions. This protocol provides an expedient method to afford various [60]fullerene-fused cyclopentanes, showing advantages of good substrate scope, short reaction time, and solvent-free and ambient reaction conditions. Furthermore, representative fullerene products have been applied in inverted planar perovskite solar cells as efficient cathode interlayers.

π-Extended Fullerenes with a Reactant Inside

Fullerene-graphene hybrids potentially exhibit unprecedented properties owing to interactive communication between the two units through a linkage. However, most of their discrete molecular structures have been still undisclosed thus far. With the recent rise in the awareness of facile access to molecular nanocarbon hybrids, we showcase novel π-extended fullerenes with a fused pyrazine or imidazole. Owing to the effective planar-curved π-conjugation, their absorption coefficients significantly increased in the visible region. Curiously enough, during the formation of π-extended fullerenes, an in situ generated NH₃ molecule was spontaneously encapsulated inside the fullerene cavity. The NH₃ molecule then underwent a timed orifice-expansion triggered by its sustained release. This is the first demonstration that fullerene captures a reactant inside, suggesting their potential usage for a sustained dosing and/or material delivery toward postfunctionalization of fullerene-graphene hybrids.

Rational Design of a Low-Dimensional and Metal-free Heterostructure for Efficient Water Oxidation: DFT and Experimental Studies

A nitrogen-doped fullerene dimer is synthesized and compounded with multi-walled carbon nanotubes (MWCNTs) to construct a low-dimensional and metal-free 0D-1D heterostructure for electrocatalytic water oxidation. The (C₅₉N)₂/MWCNTs heterostructure exhibits a highly efficient performance, as verified by both first-principles density functional theory and experimental studies. The *O → *OOH process is confirmed as the rate-determining step of water oxidation. The negatively charged N-doping leads to electronic redistribution and intermolecular charge transfer and thus reduces the uphill free energies of intermediates on the (C₅₉N)₂/MWCNTs interface. Therefore, the (C₅₉N)₂/MWCNTs heterostructure has great potential to emit light and heat in metal-free-based electrocatalytic water oxidation.

Electrocatalytic activity for proton reduction by a covalent non-metal graphene-fullerene hybrid

A non-metal covalent hybrid of fullerene and graphene was synthesized in one step via fluorographene chemistry. Its electrocatalytic performance for the hydrogen evolution reaction and durability was ascribed to intrahybrid charge-transfer phenomena, exploiting the electron-accepting properties of C₆₀ and the high conductivity and large surface area of graphene.

A metal-free electrocatalyst consisting of a covalently linked graphene–fullerene hybrid material was prepared following the chemistry of fluorographene, displaying improved hydrogen evolution reaction electrocatalytic activity and high durability.

Collective movement and thermal stability of fullerene clusters on the graphene layer

Understanding the motion characteristics of fullerene clusters on the graphene surface is critical for designing surface manipulation systems. Toward this purpose, using the molecular dynamics method, we evaluated six clusters of fullerenes including 1, 2, 3, 5, 10, and 25 molecules on the graphene surface, in the temperature range of 25 to 500 K. First, the surface motion of clusters is studied at 200 K and lower temperatures, in which fullerenes remain as a single group. The trajectories of the motion as well as the diffusion coefficients indicate the reduction of surface mobility as a response to the increase of the fullerene number. The clusters show normal diffusion at the temperature of 25 K, while they follow the super-diffusion regime at higher temperatures. The separation of fullerenes occurs at 300 K and higher temperatures. Due to the increase of vdW attraction with the increase of the fullerene number, the separation of fullerenes in larger clusters occurs at higher temperatures. The thermal energy at 500 K is sufficient to divide the large C60 clusters into smaller clusters. This energy level is related to the saturation of the interaction energy experienced by individual fullerenes, which can be estimated from the potential energy analysis. The results of simulations reveal that the separation occurs at the edge of clusters. Moreover, we studied the thermal stability of multilayer fullerene clusters on graphene. The simulation results indicate the tendency of multilayer clusters to locate on the surface, which implies the wetting property of C60s on the graphene layer.

Electronic sensors for alkali and alkaline earth cations based on Fullerene-C60 and silicon doped on C60 nanocages: a computational study

In this research, we have reported the electrical sensitivity of pristine C60 and silicon doped on C60 (SiC59) nanocages as sensors that can be used for detecting the presence of alkali (Li⁺, Na⁺, K⁺) and alkaline earth (Be²⁺, Mg²⁺, Ca²⁺) cations. The computations are carried out at the B3LYP level of theory with a 6-31G(d) basis set. The atoms in molecules (AIM) and natural bond orbital (NBO) analyses are performed to evaluate the intermolecular interactions between cations and nanocages. The physical properties of the selected complexes are also analyzed by the frontier molecular orbital, energy gap, electronegativity, chemical hardness, softness, and other quantities such as work function, number of transferred electron, and dipole moment. The results show that the adsorption process is exothermic and with increasing the charge of cations, the adsorption energies enhance. Our findings also reveal a decrease in the energy gap along with an increase in the electrical conductivity of the respective complexes. Finally, the density of state calculations is presented to confirm the obtained results.

Photoelectrochemical Response Enhancement for Metallofullerene-[12]Cycloparaphenylene Supramolecular Complexes

The photoelectrochemical properties of three metallofullerene-[12]cycloparaphenylene ([12]CPP) supramolecular complexes of Sc₃N@C₇₈⊂[12]CPP, Sc₃N@C₈₀⊂[12]CPP, and Sc₂C₂@C₈₂⊂[12]CPP were studied. It was revealed that the photocurrent responses of these supramolecular complexes show enhancement compared with those of pristine metallofullerenes, indicating the efficient photocurrent generation and promoted charge carrier transport caused by the supramolecular interaction. The results show that Sc₂C₂@C₈₂ and Sc₂C₂@C₈₂⊂[12]CPP have the strongest photocurrents. Then, by comparing the photocurrent intensities of the metallofullerene-biphenyl derivates mixture and the metallofullerene⊂[12]CPP complexes, it was demonstrated that the host–guest interaction is the key factor promoting photocurrent enhancement. At the same time, by observing the microscopic morphologies of pristine fullerenes and supramolecular complexes, it was found that the construction of supramolecules helps to improve the morphology of metallofullerenes on FTO glass. Additionally, their electrical conductivity in optoelectronic devices was tested, respectively, indicating that the construction of supramolecules facilitates the transport of charge carriers. This work discloses the potential application of metallofullerene supramolecular complexes as photodetector and photoelectronic materials.

Hierarchical CuS@ZnIn2S4 Hollow Double-Shelled p-n Heterojunction Octahedra Decorated with Fullerene C60 for Remarkable Selectivity and Activity of CO2 Photoreduction into CH4

In this work, a hollow double-shelled architecture, based on n-type ZnIn₂S₄ nanosheet-coated p-type CuS hollow octahedra (CuS@ZnIn₂S₄ HDSOs), is designed and fabricated as a p-n heterojunction photocatalyst for selective CO₂ photoreduction into CH₄. The resulting hybrids provide rich active sites and effective charge migration/separation to drive CO₂ photoreduction, and meanwhile, CO detachment is delayed to increase the possibility of eight-electron reactions for CH₄ production. As expected, the optimized CuS@ZnIn₂S₄ HDSOs manifest a CH₄ yield of 28.0 μmol g^-1 h^-1 and a boosted CH₄ selectivity up to 94.5%. The decorated C₆₀ both possesses high electron affinity and improves catalyst stability and CO₂ adsorption ability. Thus, the C₆₀-decorated CuS@ZnIn₂S₄ HDSOs exhibit the highest CH₄ evolution rate of 43.6 μmol g^-1 h^-1 and 96.5% selectivity. This work provides a rational strategy for designing and fabricating efficient heteroarchitectures for CO₂ photoreduction.

Low-dimensional heterostructures for advanced electrocatalysis: an experimental and computational perspective

Low dimensional electrocatalytic heterostructures have recently attracted significant attention in the catalysis community due to their highly tuneable interfaces and exciting electronic features, opening up new possibilities for effective nanometric control of both the charge carriers and energetic states of several intermediate catalytic species. In-depth understanding of electrocatalytic routes at the interface between two or more low-dimensional nanostructures has triggered the development of heterostructure nanocatalysts with extraordinary properties for water splitting reactions, NRR and CO₂RR. This tutorial review provides an overview of the most recent advances in synthetic strategies for 0D-1D, 0D-2D, and 2D-2D nanoheterostructures, discussing key aspects of their electrocatalytic performances from experimental and computational perspectives as well as their applications towards the development of overall water splitting and Zn-air battery devices.

Promising Graphene-Based Nanomaterials and Their Biomedical Applications and Potential Risks: A Comprehensive Review

Graphene-based nanomaterials (GBNs) have been the subject of research focus in the scientific community because of their excellent physical, chemical, electrical, mechanical, thermal, and optical properties. Several studies have been conducted on GBNs, and they have provided a detailed review and summary of various applications. However, comprehensive comments on biomedical applications and potential risks and strategies to reduce toxicity are limited. In this review, we systematically summarized the following aspects of GBNs in order to fill the gaps: (1) the history, synthesis methods, structural characteristics, and surface modification; (2) the latest advances in biomedical applications (including drug/gene delivery, biosensors, bioimaging, tissue engineering, phototherapy, and antibacterial activity); and (3) biocompatibility, potential risks (toxicity in vivo/vitro and effects on human health and the environment), and strategies to reduce toxicity. Moreover, we have analyzed the challenges to be overcome in order to enhance application of GBNs in the biomedical field.

Rational design of monolayer transition metal dichalcogenide@fullerene van der Waals photovoltaic heterojunctions with time-domain density functional theory simulations

van der Waals heterojunctions formed by transition metal dichalcogenides (TMDs) and fullerenes are promising candidates for novel photovoltaic devices due to the excellent optoelectronic properties of both TMDs and fullerenes. However, relevant experimental and theoretical investigations remain scarce to the best of our knowledge. Herein, we have first employed static density functional theory (DFT) calculations in combination with time-domain density functional theory (TDDFT) based nonadiabatic dynamics simulations to rationally evaluate the photovoltaic performances of four TMD@fullerene heterostructures, i.e. WSe₂@C₆₀, WSe₂@C₇₀, MoTe₂@C₆₀ and MoTe₂@C₇₀, respectively. Our simulation results indicate that the C₇₀-based heterostructures overall have better photoinduced electron transfer efficiencies than their C₆₀-based counterparts, among which the performance of the WSe₂@C₇₀ heterostructure is the best and the electron transfer from WSe₂ to C₇₀ almost accomplishes within 1 ps. In addition, the large build-in potential of about 0.75 eV of WSe₂@C₇₀ is beneficial for the charge separation processes. Our present work not only selects the van der Waals TMD@fullerene heterojunctions that might have excellent photovoltaic properties, but also paves the way for the rational design of novel heterojunctions with better optoelectronic performances with DFT and TDDFT simulations in the future.

Tuning the Intermolecular Electron Transfer of Low-Dimensional and Metal-Free BCN/C60 Electrocatalysts via Interfacial Defects for Efficient Hydrogen and Oxygen Electrochemistry

The development of low-dimensional (LD) supramolecular materials with multifunctional electrocatalytic properties has sparked the attention of the catalysis community. Herein, we report the synthesis of a new class of 0D-2D heterostructures composed of boron carbon nitride nanosheets (BCN NSs) and fullerene molecules (C₆₀/F) that exhibit multifunctional electrocatalytic properties for the hydrogen evolution/oxidation reactions (HER/HOR) and the oxygen evolution/reduction reactions (OER/ORR). The electrocatalytic properties were studied with varying F:BCN weight ratios to optimize the intermolecular electron transfer (ET) from the BCN NSs to the electron-accepting C₆₀ molecules. The nanohybrid supramolecular material with 10 wt % F in BCN NSs (10% F/BCN) exhibited the largest Raman and C 1s binding energy shifts, which were associated with greater cooperativity interactions and enhanced ET processes at the F/BCN interface. This synergistic interfacial phenomenon resulted in highly active catalytic sites that markedly boosted electrocatalytic activity of the material. The 10% F/BCN showed the highest tetrafunctional catalytic performance, outperforming the OER catalytic activity of commercial RuO₂ catalysts with a η₁₀ of 390 mV and very competitive onset potential values of -0.042 and 0.92 V vs RHE for HER and ORR, respectively, and a current density value of 1.47 mA cm^-2 at 0.1 V vs RHE with an ultralow ΔG_H* value of -0.03 eV toward the HOR process. Additionally, the 10% F/BCN catalyst was also used as both cathode and anode in a water splitting device, delivering a cell potential of 1.61 V to reach a current density of 10 mA cm^-2.

From 2D Graphene Nanosheets to 3D Graphene-based Macrostructures

The combination of exceptional functionalities offered by 3D graphene-based macrostructures (GBMs) has attracted tremendous interest. 2D graphene nanosheets have a high chemical stability, high surface area and customizable porosity, which was extensively researched for a variety of applications including CO₂ adsorption, water treatment, batteries, sensors, catalysis, etc. Recently, 3D GBMs have been successfully achieved through few approaches, including direct and non-direct self-assembly methods. In this review, the possible routes used to prepare both 2D graphene and interconnected 3D GBMs are described and analyzed regarding the involved chemistry of each 2D/3D graphene system. Improvement of the accessible surface of 3D GBMs where the interface exchanges are occurring is of great importance. A better control of the chemical mechanisms involved in the self-assembly mechanism itself at the nanometer scale is certainly the key for a future research breakthrough regarding 3D GBMs.

Separation of saccharides using fullerene-bonded silica monolithic columns via π interactions in liquid chromatography

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH–π and/or OH–π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC–mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide–fullerene was formed through CH–π and/or OH–π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose—with the higher dipole moment—was more strongly retained compared to other disaccharides having lower dipole moment.

Calixarene-mediated assembly of water-soluble C60-attached ultrathin graphite hybrids for efficient activation of reactive oxygen species to treat neuroblastoma cells

Unprecedented nano-carbon hybrids consisting of exfoliated ultrathin graphite (or single-walled carbon nanotubes) with pristine C₆₀ molecules attached on the surfaces have been produced in water in the presence of p-phosphonic acid calix[8]arene. The amphiphilic calixarene plays multiple roles in these processes to provide water dispersibility and π-π interactions with flexible conformations complementing curvatures of the carbon surfaces. The significantly increased water solubility and area of exposure of C₆₀ enable efficient activation of reactive oxygen species for enhanced phototoxicity to SH-SY5Y human neuroblastoma cell line under laser irradiation.

Noncovalent Functionalization of Few-Layered Antimonene with Fullerene Clusters and Photoinduced Charge Separation in the Composite

Few-layered antimonene (FLSb) nanosheets were noncovalently functionalized with fullerene C₆₀ clusters by quick addition of a poor solvent (i.e., acetonitrile) into a mixed dispersion of FLSb and C₆₀ in a good solvent (i.e., toluene). In a flash-photolysis time-resolved microwave conductivity (FP-TRMC) measurement, the FLSb-C₆₀ composite, (FLSb+C₆₀ )_m , showed a rapid rise in transient conductivity, whereas no conductivity signal was observed in the single components, FLSb and C₆₀ . This demonstrated the occurrence of photoinduced charge separation between FLSb and C₆₀ in (FLSb+C₆₀ )_m . Furthermore, a photoelectrochemical device with an electrophoretically deposited (FLSb+C₆₀ )_m film exhibited an enhanced efficiency of photocurrent generation, compared to those of the single-components, FLSb and C₆₀ , due to the photoinduced charge separation between FLSb and C₆₀ . This work provides a promising approach for fabrication of antimonene-organic molecule composites and paves the way for their application in optoelectronics.

Carnosine-Modified Fullerene as a Highly Enhanced ROS Scavenger for Mitigating Acute Oxidative Stress

Fullerenes are known as highly efficient scavengers for reactive oxygen species (ROSs). In this study, a carnosine-modified fullerene derivative (C₆₀-Car) was synthesized via a one-step nucleophilic addition reaction. C₆₀-Car forms nanoparticles (NPs) readily in water at neutral pH and room temperature through self-assembly. The C₆₀-Car NPs were found to possess good water solubility, biocompatibility, and excellent ROSs scavenging capability. The scavenging efficiency of ROSs is as high as 92.49% and significantly better than that of hydroxyfullerene (C₆₀-OH NPs, 70.92%) and l-carnosine. Furthermore, C₆₀-Car NPs showed strong cytoprotective ability against H₂O₂-induced damage to the normal human fetal hepatocyte cells (L-02) and human epidermal keratinocytes-adult (HEK-a) cells at a lower concentration of 2.5 μM. In contrast, C₆₀-OH NPs showed a minor cytoprotective effect on cells at a high concentration of 10 μM. The excellent properties of such a fullerene derivative, C₆₀-Car, can be attributed largely to the involvement of l-carnosine with biological activity and antioxidant property, which make it better for biomedicine, and it may provide a new strategy for mitigating acute oxidative stress based on fullerene materials.

Noble metal-free two dimensional carbon-based electrocatalysts for water splitting

Noble metal materials are widely employed as benchmark electrocatalysts to achieve electrochemical water splitting which comprises of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, the high cost and scarcity limit the wide ranging commercial applications of noble metal-based catalysts. Development of noble metal-free two dimensional (2D) carbon-based materials can not only reduce the consumption of noble metals, but also create materials with the characteristics of high active surface area, abundance, easy functionalization, and chemical stability, which may carve a way to promising electrochemical water splitting. In this review, noble metal-free 2D carbon-based electrocatalysts, including heteroatom (B, S, N, P, F, and O) doped graphene, 2D porous carbons modified with heteroatoms and/or transition metals, and 2D carbon-based hybrids are introduced as cost-effective alternatives to the noble metal-based electrocatalysts with comparable efficiencies to conduct HER, OER, and overall water splitting. This review emphasizes on current development in synthetic strategies and structure–property relationships of noble metal-free 2D carbon-based electrocatalysts, together with major challenges and perspectives of noble metal-free 2D carbon-based electrocatalysts for further electrochemical applications.

PffBT4T-2OD Based Solar Cells with Aryl-Substituted N-Methyl-Fulleropyrrolidine Acceptors

Novel C60 and C70 N-methyl-fulleropyrrolidine derivatives, containing both electron withdrawing and electron donating substituent groups, were synthesized by the well-known Prato reaction. The corresponding highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels were determined by cyclic voltammetry, from the onset oxidation and reduction potentials, respectively. Some of the novel fullerenes have higher LUMO levels than the standards PC61BM and PC71BM. When tested in PffBT4T-2OD based polymer solar cells, with the standard architecture ITO/PEDOT:PSS/Active-Layer/Ca/Al, these fullerenes do not bring about any efficiency improvements compared to the standard PC71BM system, however they show how the electronic nature of the different substituents strongly affects the efficiency of the corresponding organic photovoltaic (OPV) devices. The functionalization of C70 yields a mixture of regioisomers and density functional theory (DFT) calculations show that these have systematically different electronic properties. This electronic inhomogeneity is likely responsible for the lower performance observed in devices containing C70 derivatives. These results help to understand how new fullerene acceptors can affect the performance of OPV devices.

Functionalized Hybridization of 2D Nanomaterials

The discovery of graphene and subsequent verification of its unique properties have aroused great research interest to exploit diversified graphene-analogous 2D nanomaterials with fascinating physicochemical properties. Through either physical or chemical doping, linkage, adsorption, and hybridization with other functional species into or onto them, more novel/improved properties are readily created to extend/expand their functionalities and further achieve great performance. Here, various functionalized hybridizations by using different types of 2D nanomaterials are overviewed systematically with emphasis on their interaction formats (e.g., in-plane or inter plane), synergistic properties, and enhanced applications. As the most intensely investigated 2D materials in the post-graphene era, transition metal dichalcogenide nanosheets are comprehensively investigated through their element doping, physical/chemical functionalization, and nanohybridization. Meanwhile, representative hybrids with more types of nanosheets are also presented to understand their unique surface structures and address the special requirements for better applications. More excitingly, the van der Waals heterostructures of diverse 2D materials are specifically summarized to add more functionality or flexibility into 2D material systems. Finally, the current research status and faced challenges are discussed properly and several perspectives are elaborately given to accelerate the rational fabrication of varied and talented 2D hybrids.

Unusual Sonochemical Assembly between Carbon Allotropes for High Strain-Tolerant Conductive Nanocomposites

Facile methods toward strain-tolerant graphene-based electronic components remain scarce. Although being frequently used to disperse low-dimensional carbonaceous materials, ultrasonication (US) has never been reliable for fabricating stretchable carbonaceous nanocomposite (SCNC). Inspired by the unusual sonochemical assembly between graphene oxide (GO) and carbon nanotube (CNT), we verified the roots-like GO-CNT covalent bonding, rather than just π-π conjugation, was formed during US. In addition, the shockwave-induced collision in the binary-component system enables a burst of fragmentation at the early stage, spatially homogeneous hybridization, and time-dependent restoration of graphitic domains. All of the above are distinct from extensive fragmentation of a conventional single-component system and π-π conjugative assembly. The optimized SCNC exhibits conductivity comparable to reduced monolayer GO and outperforms π-π assemblies in retaining electrical conductance at a strain of 160%-among one of the best reported stretchable conductors. Raman analysis and mechanics simulation confirm the dominant role of counterweighing between the intrinsic and external strains on the mechano-response and durability of SCNC. This work suggests the guideline of creating multiple-component sonochemical systems for various functional nanocomposites.

Bidirectional charge-transfer behavior in carbon-based hybrid nanomaterials

In recent years there has been a growing interest in finding materials revealing bidirectional charge-transfer characteristics, that is, materials behaving as an electron donor or an acceptor in the presence of redox and photoactive addends, for optoelectronic applications. In this respect, carbon-based nanostructures, such as graphene and carbon nanotubes, have emerged as promising nanomaterials for the development of hybrid systems for bidirectional charge transfer, whose behaviour can be switched from donor-type to acceptor-type by simply changing the electroactive counterpart to which they are anchored. In this review we provide an overview of the main advances that have been made over the past few years in carbon-based hybrid architectures involving different types of carbon nanostructures and photosensitizers. In particular, carbon nanotube and graphene-based hybrid systems will be highlighted.