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Monometallic cyanide clusterfullerenes (CYCFs) with a chemical formula of MNC@C2n represent a new type of clusterfullerene discovered in recent years; the encapsulated metal types are still limited to yttrium and terbium thus far. This makes the stabilization mechanism of the host fullerene cages upon the variation of internal MNC clusters unclear. Herein, for the first time, four novel Lu-based CYCFs, namely LuNC@C2v(19138)-C76, LuNC@C2(5)-C82, LuNC@Cs(6)-C82, and LuNC@C2v(9)-C82, have been successfully obtained and characterized using a combination of mass spectrometry, vis-NIR, single-crystal X-ray diffractometry, and cyclic voltammetry. In particular, the X-ray results of LuNC@C2v(19138)-C76 and LuNC@C2(5)-C82 unambiguously demonstrated that the internal LuNC unit assumes a nearly linear configuration in the small C76 cage but a confined triangle in the large C82 one, demonstrating the critical role of the cage structure in regulating the cluster configuration. Further theoretical calculations reveal that the linear and triangular configurations of LuNC clusters are governed by the strong and weak Lu-cage coordination interactions in the C2v(19138)-C76 and C2(5)-C82 cages, respectively. In addition, the exact positions of the internal N and C atoms inside the two cages were well defined by combining the crystallographic data with theoretical calculations, showing that the N atom always resides closer to the metal atom to pursue stronger electrostatic interactions.

Enhancing the exchange interaction between magnetic ions is a long-term target in molecular magnetism. Endohedral metallofullerenes (EMFs) provide a possibility for achieving such a goal by imprisoning multiple magnetic centers inside the confined inner space of a fullerene cage. Here, we report a new member of dimetallic azafullerene Dy2@C79N via crystallographic determination for the first time. Magnetic studies indicate that the strong ferromagnetic coupling between lanthanide ions and unpaired electrons enables Dy2@C79N to be a favorable SMM with large energy barrier of U = 669 K and observable hysteresis loops below 24 K.

Synthesis of polymeric nitrogen compounds is a formidable task due to the proneness of nitrogen to the formation of N ≡ N triple bond, one of the strongest chemical bonds known. Here, we report an arc-discharge approach to successfully stabilize the elusive four-membered nitrogen ring (cyclo-N4) in an unprecedented endohedral metallofullerene Dy2N4@C81N (Dy-I). Its molecular structure has been unambiguously determined by X-ray crystallography to show a covalently bonded cyclo-N4 plane bridging two dysprosium ions inside an aza[82]fullerene cage, highlighting the stabilization of cyclo-N4 as a concurrent result of fullerene encapsulation and metal coordination. Our computational results further reveal a six-center-one-electron (6c-1e) bond delocalized over the inverse-sandwich Dy-N4-Dy cluster. This chemical peculiarity stems from the diffuse radical character of the highly anionic cyclo-N43− ligand, which is confirmed by electron paramagnetic resonance (EPR) spectrum of Y2N4@C81N (Y-I).

The photoluminescence of lanthanide ions inside fullerenes is usually very weak due to the quenching effect of the fullerene cage. In the case of Er@C82, the near-infrared emission from the Er3+ io...

To design molecular spin qubits with enhanced quantum coherence, a control of the coupling between the local vibrations and the spin states is crucial, which could be realized in principle by engineering molecular structures via coordination chemistry. To this end, understanding the underlying structural factors that govern the spin relaxation is a central topic. Here, we report the investigation of the spin dynamics in a series of chemically designed europium(II)‐based endohedral metallofullerenes (EMFs). By introducing a unique structural difference, i. e. metal‐cage binding site, while keeping other molecular parameters constant between different complexes, these manifest the key role of the three low‐energy metal‐displacing vibrations in mediating the spin‐lattice relaxation times (T 1). The temperature dependence of T 1 can thus be normalized by the frequencies of these low energy vibrations to show an unprecedentedly universal behavior for EMFs in frozen CS2 solution. Our theoretical analysis indicates that this structural difference determines not only the vibrational rigidity but also spin‐vibration coupling in these EMF‐based qubit candidates., The investigation of the spin dynamics in a series of chemically designed europium(II)‐based endohedral metallofullerenes (EMFs) is reported. As a unique structural difference, metal‐cage binding site can be introduced in EMFs and is demonstrated to play a key role in determining rigidity of the three low‐energy metal‐displacing vibrations and the spin‐lattice relaxation times (T 1). Normalized by the frequencies of these vibrations, the temperature dependence of T 1 shows a universal behavior for different compounds in frozen CS2 solution.

Enhancing the exchange interaction between magnetic ions is a long-term target in molecular magnetism. Endohedral metallofullerenes (EMFs) provide a possibility for achieving such a goal by imprisoning multiple magnetic centers inside the confined inner space of a fullerene cage. Here, we report a new member of dimetallic azafullerene Dy2@C79N via crystallographic determination for the first time. Magnetic studies indicate that the strong ferromagnetic coupling between lanthanide ions and unpaired electrons enables Dy2@C79N to be a favorable SMM with large energy barrier of U = 669 K and observable hysteresis loops below 24 K.

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M2@C79N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd2@C79N for the first time. This molecular magnet with a collective high-spin ground state (S = 15/2) generated by strong magnetic coupling (JGd-Rad = 350 ± 20 cm-1) has been unambiguously validated by magnetic susceptibility experiments. Gd2@C79N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover's searching algorithm proposed by Leuenberger and Loss.

Yujie Shi,1 Zujin Shi,2 Suxin Li,1 Yuan Zhang,3 Bing He,1 Dong Peng,4 Jie Tian,4 Ming Zhao,5 Xueqing Wang,1 Qiang Zhang1 1Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, School of Pharmaceutical Sciences, 2Beijing National Laboratory for Molecular Sciences, State Key Lab of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, People’s Republic of China; 3Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA; 4Key Laboratory of Molecular Imaging of Chinese Academy of Sciences, Institute of Automation, Chinese Academy of Sciences, 5Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, People’s Republic of China Abstract: Single-wall carbon nanohorns (SWCNHs), which have multitudes of horn interstices, an extensive surface area, and a spherical aggregate structure, offer many advantages over other carbon nanomaterials being used as a drug nanovector. The previous studies on the interaction between SWCNHs and cells have mostly emphasized on cellular uptake and intracellular trafficking, but seldom on epithelial cells. Polar epithelium as a typical biological barrier constitutes the prime obstacle for the transport of therapeutic agents to target site. This work tried to explore the permeability of SWCNHs through polar epithelium and their abilities to modulate transcellular transport, and evaluate the potential of SWCNHs in drug delivery. Madin-Darby canine kidney (MDCK) cell monolayer was used as a polar epithelial cell model, and as-grown SWCNHs, together with oxidized and fluorescein isothiocyanate-conjugated bovine serum albumin-labeled forms, were constructed and comprehensively investigated in vitro and in vivo. Various methods such as transmission electron microscopy and confocal imaging were used to visualize their intracellular uptake and localization, as well as to investigate the potential transcytotic process. The related mechanism was explored by specific inhibitors. Additionally, fast multispectral optoacoustic tomography imaging was used for monitoring the distribution and transport process of SWCNHs in vivo after oral administration in nude mice, as an evidence for their interaction with the intestinal epithelium. The results showed that SWCNHs had a strong bioadhesion property, and parts of them could be uptaken and transcytosed across the MDCK monolayer. Multiple mechanisms were involved in the uptake and transcytosis of SWCNHs with varying degrees. After oral administration, oxidized SWCNHs were distributed in the gastrointestinal tract and retained in the intestine for up to 36h probably due to their surface adhesion and endocytosis into the intestinal epithelium. Overall, this comprehensive investigation demonstrated that SWCNHs can serve as a promising nanovector that can cross the barrier of polar epithelial cells and deliver drugs effectively. Keywords: carbon nanohorns, epithelial cells, transport mechanisms, nanocarriers, MSOT imaging

Graphene quantum dots (GQDs) have attracted great attention because of their possible applications in various fields. Here we report a facile one-step method for the fabrication of a type of white-light-emitting GQD (W-GQD) by NaBH4 reduction. The highly-pure white-light emission of the obtained W-GQDs was confirmed by calculating the Commission International de l’Eclairage (CIE) 1931 chromaticity parameters (x = 0.30, 0.36) from the fluorescence luminescence data. We observed an important increase in the absolute quantum yield from 0.20% to 3.62% before and after the chemical reduction. The influence of the interface characteristics on the emission properties was analyzed by UV-vis, Fourier transform infrared, and X-ray photoelectron spectroscopies. The results illustrated that the carboxyl and epoxy groups were reduced into hydroxyl groups and that the five- and six-membered lactol groups transformed into aromatic carboxylic acid and hydroxyl groups. The chemical modifications enhanced the electron density of the π structure and also suppressed the non-radiative recombination, resulting in a bright white-light emission. Furthermore, the as-prepared W-GQDs were successfully utilized for the fabrication of a white-light-emitting diode.

Substituting a carbon atom on the carbon cage (C2n) by nitrogen can lead to a special kind of fullerene called azafullerene (C2n-1N), which tends to form a dimer due to its paramagnetic property. When an azafullerene monomer, acting as a nanocontainer, encounters metal atoms or clusters, the extra electron generated by the nitrogen substitution would be transferred to the internal metal or cluster center. This may lead to the enhancement of metal-metal interaction, the capture of metastable species and concomitantly some interesting chemical and physical properties. Here, we have synthesized and crystallographically characterized two novel metalloazafullerenes Dy2@C79N and Dy2N4@C81N with quasi-C80-Ih (7) and quasi-C82-C 3v (8) cages, respectively. Owing to the strong exchange coupling between two dysprosium ions via radical bridges, Dy2@C79N behaves as an excellent single-molecule magnet with large energy barrier of U = 669 ± 7 K and observable hysteresis loops below 24 K. Dy2N4@C81N is the first entity of capturing the unstable four-membered nitrogen ring (cyclo-N4) with definitive structure characterized by single-crystal x-ray diffraction (XRD) analysis. The results show that a planar cyclo-N4 coordinated with two dysprosium ions to form a distorted octahedral cluster inside the C81N cage. These works will inspire further exploration of the properties and applications of metalloazafullerenes. Keywords: Metalloazafullerene; Single-molecule magnet; Four-membered nitrogen ring References: [1] G. Velkos; D. S. Krylov; K. Kirkpatrick; L. Spree; V. Dubrovin; B. Buchner; S. M. Avdoshenko; V. Bezmelnitsyn; S. Davis; P. Faust; J. Duchamp; H. C. Dorn; A. A. Popov, Angew. Chem. Int. Ed., 2019, 58, 5891-5896. [2] Z. Hu; B. W. Dong; Z. Liu; J. J. Liu; J. Su; C. Yu; J. Xiong; D. E. Shi; Y. Wang; B. W. Wang; A. Ardavan; Z. Shi; S. D. Jiang; S. Gao, J. Am. Chem. Soc., 2018, 140, 1123-1130. [3] Y. Wang; J. Xiong; J. Su; Z. Hu; F. Ma; R. Sun; X. Tan; H. L. Sun; B. W. Wang; Z. Shi; S. Gao, Nanoscale, 2020, 12, 11130–11135.

Synthesis of chemically stable non-precious-metal 3d-block transition metal nanocatalysts for catalytic syngas conversion remains a great challenge, since the nanocatalysts are usually too active to remain stable under ambient conditions. In situ grown (N-doped) graphene-encapsulated Ni nanoparticles (NPs) (Ni@G, Ni@G-N) were successfully obtained by a simple route via an arc-discharge method. The Ni@G composite is composed of a graphene sheath and a metallic nickel core. The carbon layer can prevent the inner Ni NPs from being etched when they are exposed to air, H2O2 or acid. Moreover, the as-prepared Ni@G exhibit excellent catalytic activity and methane selectivity and high stability in the methanation reaction. The catalytic performance can be further improved by doping nitrogen into the graphene shell. This method provides a good procedure for graphene encapsulation of non-precious-metal nanoparticles.

Palladium nanoparticles with a diameter of 2–4 nm supported on nitrogen and boron dual-doped single-wall carbon nanohorns (Pd-NBCNHs) are synthesized via a one-step method and their electrocatalytic activities are investigated for the oxygen reduction reaction (ORR) in alkaline media. The electrochemical results demonstrate that the oxygen reduction peak potential of Pd-NBCNHs is similar to that of commercial 20% Pt–C. Furthermore, Pd-NBCNHs show a more positive half-wave potential than 20% Pt–C and display better long-term stability and resistance to methanol than 20% Pt–C, which is attributed to the synergetic effect of the Pd nanoparticles and NBCNHs. As NBCNHs have abundant pyrrolic nitrogen, charged sites and defective structures, they not only act as a carrier, but also provide the active sites for oxygen adsorption during the oxygen reduction reaction process. The outstanding electrochemical performance makes Pd-NBCNHs promising to be applied in fuel cells.

Through a facile one-pot solvothermal approach, nano-sized SnS 2 particles were homogeneously anchored on single-walled carbon nanotubes (SWCNTs) for the first time. As an anode material for lithium ion battery, the SnS 2 /SWCNTs hybrid exhibits excellent rate capacity (about 498 mA h g −1 at 2000 mA g −1 ) and good cycle stability (about 509 mA h g −1 at 1000 mA g −1 after 100 cycles). The improved electrochemical performance can be attributed to the use of SWCNTs, which not only serve as templates to restrict the size of SnS 2 particles during synthesis, and also provide flexible conductive matrix to buffer the volume change during cycling process.

Single-walled carbon nanohorns (SWCNHs) are seldom used as electromagnetic (EM) wave absorption materials due to their inferior impedance matching resulting from their high dielectric constant. In this work, decorated with 35.6 wt% Fe3O4 nanoparticles, the as-prepared composite displays a significantly enhanced EM wave absorption ability because of the improved impedance matching, electric polarization and interfacial polarization. Specifically, the maximum reflection loss of this composite with a thickness of 5.8 mm is −38.84 dB at 3.72 GHz in the S-band. The bandwidth of absorption exceeding −10 dB is 9.2 GHz (from 3.2 GHz to 12.4 GHz) with an absorber thickness of 2–6 mm. What is more, a second absorption peak with a reflection loss no less than −10 dB appears when the absorber thickness is over 4 mm.

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M

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Synthesis of nanomaterials under high temperature is always a challenge. Here, we provide a new approach to prepare a nanostructured phosphor at high temperature with the aid of the arc-discharge method. Eu 3+ -doped La 2 O 3 /La 2 O 2 CO 3 nanoparticles were obtained from annealing the La 2 O 3 :Eu/graphene composite at 600–750 °C in air. Innovatively, the La 2 O 3 :Eu/graphene composite was first produced by the arc-discharge method. The graphene sheets in the composite separate the oxide nanoparticles to avoid nanoparticle agglomeration and grain growth during the high-temperature annealing. This nanostructured Eu 3+ -doped La 2 O 3 /La 2 O 2 CO 3 was observed to have an intense photoluminescence intensity, comparable to the sample from conventional solid state reaction.

Polydopamine is not only a multifunctional biopolymer with promising optoelectronic properties but it is also a versatile coating platform for different surfaces. The structure and formation of polydopamine is an active area of research. Some studies have supposed that polydopamine is composed of covalently bonded dihydroxyindole, indoledione, and dopamine units, but others proposed that noncovalent self-assembly contributes to polydopamine formation as well. However, it is difficult to directly find the details of supramolecular structure of polydopamine via self-assembly. In this study, we first report the graphite-like nanostructure observed in the carbonized polydopamine nanoparticles in nitrogen (or argon) environment at 800 °C. Raman characterization, which presents the typical D band and G band, confirmed the existence of graphite-like nanostructures. Our observation provides clear evidence for a layered-stacking supramolecular structure of polydopamine. Particularly, the size of graphite-like domains is similar to that of disk-shaped aggregates hypothesized in previous study about the polymerization of 5,6-dihydroxyindole [ Biomacromolecules 2012 , 13 , 2379 ]. Analysis of the hierarchical structure of polydopamine helps us understand its formation.

Nitrogen-doped graphene treated with ammonia under different temperatures was used as the catalysts for the epoxidation of trans-stilbene and styrene at 373 K. NG-800 (N-doped graphene treated at 800 °C for 8 h) performed the best and gave the highest recyclable catalytic activity for the epoxidation of trans-stilbene, with 95.8% conversion and 94.4% selectivity to trans-stilbene epoxide. The catalytic center has been identified with the reaction mechanism elucidated by DFT calculation.

In this paper, we present the RF transmission characteristics of graphene-based coplanar waveguide (CPW) lines with different structure dimensions, including widths of signal trace, widths of ground plane, and spacings between the CPW signal and ground lines. It has been demonstrated that the energy loss of graphene-based CPW in the RF transmission process can be decreased by tuning the CPW dimensions. To further reduce the energy loss, both high-quality graphene and good contact between metal and graphene are required.

We herein report a facile and effective ultrasonication method to non-covalently functionalize graphene with copper phthalocyanine-3,4′,4″,4‴-tetrasulfonic acid tetrasodium salt (TSCuPc) as a promising catalyst support for Pt nanoparticles. With the assistance of TSCuPc, Pt nanoparticles are homogeneously deposited on the surface of graphene, and their dispersivity and electrochemical active surface area (ECSA) are obviously enhanced. Studies of cyclic voltammetry and chronoamperometry demonstrate that the as-prepared Pt/TSCuPc–graphene catalyst exhibits much higher electrocatalytic activity and stability than the Pt/graphene and commercial Pt/C catalysts for methanol oxidation. It is concluded that the strategy of TSCuPc-functionalized graphene with Pt catalysts will be potential in design and synthesis of the highly efficient electrocatalysts for DMFCs applications.

A glassy carbon electrode (GCE) was modified with nanopeapods formed by ferrocene filled single-walled carbon nanotubes (Fc@SWNTs). The modified electrode showed bi-directional electrocatalysis toward dopamine (DA), which suggested a synergistic effect of ferrocene and carbon nanotubes. Bi-directional detection of DA was realized based on the modified electrode.

A negatively charged glassy carbon electrode (GCE) was formed through the electrochemical modification of sulfanilic acid (ABS). Subsequently, graphene composites functionalized with copper phthalocyanine-3,4′,4″,4‴-tetrasulfonic acid tetrasodium salt (TSCuPc) or alcian blue pyridine variant (AB) were assembled layer-by-layer (LbL) via alternate electrostatic adsorption onto the ABS/GCE surface to obtain a uniform and stable graphene multilayer film modified electrode. With glucose oxidase (GOD) as an enzyme model, a novel GOD/Nafion/(LbL) 3.5 /ABS/GCE electrochemical biosensor has been developed. SEM and Raman spectra were utilized to characterize the functionalized graphene nanocomposites and modified electrodes. The electrochemical performance of the biosensor was investigated by cyclic voltammetry. The results demonstrated that the graphene multilayer film significantly enhanced the electrocatalytic activity of the modified electrode toward O 2 reduction. Based on the O 2 consumption during the oxidation process of glucose, the as-prepared biosensor exhibited a low detection limit of 0.05 mmol L −1 , excellent reproducibility, stability, sensitivity and selectivity, and its response was linear up to 8 mmol L −1 glucose concentration. Accordingly, the multilayer film consisting of copper phthalocyanine functionalized graphene nanocomposites offers a novel and effective platform for the electrochemical biosensing applications.

A novel composite of single-wall carbon nanohorns (SWCNHs） supported nanoporous anatase TiO 2 , TiO 2 /SWCNHs, is facilely synthesized by hydrolysis of tetrabutoxytitanium in the presence of SWCNHs. The phase structure, morphology, and pore structure of TiO 2 /SWCNHs are investigated with transmission electron microscopy, X-ray diffraction and the nitrogen adsorption and desorption isotherms measurements. The TiO 2 /SWCNHs composite materials show excellent electrochemical properties, and are expected to be a promising anode material for high power density lithium ion batteries. It is found that the TiO 2 /SWCNHs composite not only exhibits excellent cycling performance, but also shows high rate capability as anode materials by the cyclic voltammetry and constant current discharge–charge tests. Especially, the specific charge capacity of the TiO 2 /SWCNHs composite remains as high as 100 mAh g −1 at a high rate of 30 C, which is four times higher than that of pure TiO 2 anode materials. The SWCNHs with high rate production in low cost have hopeful application to electrode materials for lithium ion batteries.

Inductors are key passive components in analog circuits. The graphene is considered as the possible materials to develop the nanoscale inductors since the graphene has many advantages over Cu and Al. In this paper, we report the key fabrication processes and the performance of graphene-based inductors.

The relatively high sheet resistance of graphene compared with indium tin oxide (ITO) blocks the applications of graphene as transparent electrodes in organic light-emitting diodes. A novel copper (Cu)/graphene composite electrode is presented and employed as the anode of a top-emission organic light-emitting diode with the structure of Cu/graphene/V2O5/NPB/Alq3/Alq3: C545T/Bphen: Cs2CO3/Sm/Au. The Cu/graphene composite electrodes are fabricated by growing graphene directly on Cu substrates via the chemical vapor deposition method without any transfer process. The maxima of current efficiency and power efficiency of a typical Cu/graphene composite anode device reach 6.1 cd/A and 7.6 lm/W, respectively, which are markedly higher than those of the control devices with a graphene anode, a Cu anode or an ITO anode. The low sheet resistance of the composite electrode, the high quality of graphene without any transfer process and the avoidance of wave guiding loss in glass or polyethylene terephthalate substrates result in the improvements of light emission efficiencies.

Boron-, phosphorus-, nitrogen-doped and co-doped single-wall carbon nanohorns were produced using an arc-vaporization method. These as-prepared doped materials consist of uniform isolated nanohorns and exhibit greatly enhanced catalytic capabilities in the reduction reaction of nitrobenzene and a volcano-shape trend between their activities with a B dopant content is found. Moreover, the B-C3 and P-C3 species in doped nanohorns might act as the acidic and basic sites to promote this reaction.

We report a first electron diffraction study of the C60s packing inside individual single-walled carbon nanotubes (C60s at SWCNT or peapod). Diffraction patterns from a single peapod were recorded using a nanometer-sized electron beam at 80 kV. Determination of the peapod structure, including the diameter (D) and chiral angle of the SWCNT, and the average spacing between C60s along the tube direction ( Z C 60 ) are performed. The determined Z C 60 increases from around 9.03 to 9.69 A as D increases from around 14.17 to 14.38 A, while in large diameter SWCNTs with D larger than 14.5 A, a significant reduction in Z C 60 takes place. Molecular dynamics (MD) simulations reproduce the same reduction in Z C 60 , due to the well-known linear-to-zigzag transition. More importantly, prior to the linear-to-zigzag transition, a 1D-to-3D transition of C60s configuration is predicted. The resulting expansion of accessible volume is likely to contribute to the observed increasing Z C 60 as a function of increasing SWCNT diameter before D reaching 14.5 A.

A highly durable and active nanocomposite cathode catalyst (Pt/NSWCNH) is assembled with “unprotected” Pt nanoclusters and nitrogen-doped single-wall carbon nanohorns (NSWCNH) as building blocks by a convenient process. The specific catalytic activity and mass catalytic activity for the oxygen reduction reaction over Pt/NSWCNH is 1.60 and 1.75 times as high as those over a commercial Pt/C catalyst, respectively. There is no obvious loss in the catalytic activity of Pt/NSWCNH after potential cycling from 0.6 to 1.1 V versus RHE for 15,000 cycles at 30 °C, under the oxidizing conditions for the electrochemically catalytic reduction of O 2 . TEM characterization results reveal that, during the accelerated aging tests, Pt nanoparticles in Pt/NSWCNH are more stable than that in Pt/C-JM, showing a low increase in the particle size.

Electrochemistry of double-wall carbon nanotubes (DWCNTs) encapsulating C 60 (C 60 @DWCNT) have been studied by preparing a C 60 @DWCNT modified electrode, and three pairs of reversible electro-reduction waves corresponding to electron transfer reactions of C 60 inside DWCNTs have been obtained in a mixed solvent of toluene and acetonitrile (4:1, v:v) containing tetrabutylammonium cation as supporting electrolyte, which indicates that DWCNTs act as molecular wires to allow electrical communication between the underlying electrode and the redox-active guest C 60 . The influencing factors on the electrochemistry of C 60 @DWCNT modified electrodes have been investigated. The results suggest that the voltammetric behavior of C 60 @DWCNT is dependent on the nature of the supporting electrolyte and the solvent system. In addition, spectral characterization of the C 60 @DWCNT modified electrodes before and after electrochemical scanning reveals interaction between C 60 and DWCNT and verifies the reduction of C 60 encapsulated in DWCNTs. C 60 molecules inside DWCNTs retains their redox activity, and can also act as an electron-transfer mediator to electrocatalyze the reduction of halohydrocarbon.

We demonstrate the potential of electrons for single molecule diffraction and imaging using C 60 molecules confined inside single-walled carbon nanotubes (C 60 s@SWCNT or peapod) as a model system. A 25 nm diameter electron beam from a field emission gun source is used to record diffraction patterns from individual peapods using imaging plates. The electron beam illuminates about 25 C 60 molecules. Experimentally, we found that the molecules diffract inside ∼15% of the host nanotubes. With the help of simulations, we explore the limits of electron molecular diffraction and its sensitivity to the molecular configurations. We show that the combination of electron diffraction and electron direct imaging provides the best approach to single molecule imaging.

A simple and effective glucose biosensor based on immobilization of glucose oxidase (GOD) in graphene (GR)/Nafion film was constructed. The results indicated that the immobilized GOD can maintain its native structure and bioactivity, and the GR/Nafion film provides a favorable microenvironment for GOD immobilization and promotes the direct electron transfer between the electrode substrate and the redox center of GOD. The electrode reaction of the immobilized GOD shows a reversible and surface-controlled process with the large electron transfer rate constant (ks) of 3.42±0.08 s−1. Based on the oxygen consumption during the oxidation process of glucose catalyzed by the immobilized GOD, the as-prepared GOD/GR/Nafion/GCE electrode exhibits a linear range from 0.5 to 14 mmol·L−1 with a detection limit of 0.03 mmol·L−1. Moreover, it displays a good reproducibility and long-term stability.

Electrochemical properties of a new class of endohedral functionalized carbon nanomaterial, ferrocene-filled double-walled carbon nanotubes (Fc@DWNTs) have been investigated by preparing an Fc@DWNTs modified glassy carbon electrode (Fc@DWNTs/GCE). In an aqueous LiClO4 solution, one pair of redox peaks corresponding to the surface-confined Fc+/Fc couple was observed, suggesting that Fc molecules encapsulated inside DWNTs retain their electrochemical activity. Moreover, the Fc@DWNTs/GCE showed good stability because DWNTs could overcome the leaching of Fc from the modified electrode. Electrocatalytic oxidation of dopamine (DA) at the Fc@DWNTs modified electrodes was also obtained, indicating that encapsulated Fc molecules can serve as good electron-transfer mediators. In addition, due to the peculiar structure of Fc@DWNTs, direct electroreduction of oxidation product of DA was also observed. An electrochemical sensor for DA has been constructed based on Fc@DWNTs and a kind of cation exchange membrane, Nafion, which played a key role in the selectivity of the sensor. Amperometric measurements were conducted in the presence of a large excess of ascorbic acid (AA). The limit of detection was found to be 0.3 μM based on S/N of 3.

We demonstrated a simple method to produce superhydrophobic polyvinylidene fluoride (PVDF)/graphene porous materials. The hybrid PVDF/graphene gel was formed by the diffusion of non-solvent (methanol or water) into PVDF/graphene suspension in N,N-dimethylformamide (DMF). By carefully replacing DMF in aged gels by water, gel samples were freeze-dried to produce skinless porous materials. This drying method effectively avoids pore-shrinkage because of the capillary force in the drying process of gels, giving porous materials with high specific surface area and surface roughness. Furthermore, compared with pure PVDF porous materials, the addition of small amount of graphene in hybrid gels not only influences the crystallization of PVDF, but also leads to a dramatically morphology change which significantly increases their surface roughness in nanoscale, thus generating superhydrophobic porous PVDF/graphene materials.

Fully-surrounded Zn3P2/ZnS core/shell nanowires (NWs) were synthesized for the first time via a two-step method: a catalyst free chemical vapor deposition followed by a low-pressure vulcanization process. Field emission scanning electron microscopy, high-resolution transmission electron microscopy, and high-angle angular dark field scanning transmission electron microscopy were used to characterize the morphologies, crystal structure, and element composition of the core/shell NWs. The band structure analysis demonstrates that the Zn3P2/ZnS core–shell NW type-II heterostructures have bright potential in photovoltaic nanodevice applications. The core/shell NW growth method used here can be extended to other material system.

Electron microscopy with advances in aberration correction has the power to resolve atoms in single molecules. However, its application is limited by electron irradiation induced molecular motions. A better understanding of damage mechanisms is required to achieve the full potential of electron imaging. Here, we report a direct observation of molecular motions stimulated by an electron beam, which allows us to study the breakdown and formation of molecular bonds using C(60)'s encapsulated inside single-walled carbon nanotubes as a model system. An activation energy of 100 s meV is estimated for the observed molecular motions based on van der Waals interactions. We demonstrate that the molecular confinement can significantly increase the electron energy threshold for breaking the vdW bonds.

Carbon nanotubes filled with metals and semiconductors have been regarded as one of the most promising materials for nanodevices. Here, we demonstrate a simple and effective method to produce tungsten trioxide (WO3) and tungsten (W) nanowires with diameters of below 4 nm inside double-walled carbon nanotubes (DWCNTs). First, the precursors, i.e., phosphotungstic acid (HPW, H3PW12O40) molecules, are successfully introduced into DWCNTs. Subsequent decomposition and reduction lead to the formation of WO3 and W nanowires inside DWCNTs. The products were carefully characterized by high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. FTIR spectra provide a direct proof that the HPW molecules enter the DWCNTs as an ionic state, i.e., PW12O40(3-) and H+, instead of the molecular state. HRTEM analysis shows that the diameter of the WO3 nanowires inside DWCNTs is 1.1-2.4 nm with the average length of 16-18 nm, and that for W nanowires is 1.2-3.4 nm with the average length of 15-17 nm. Meanwhile, DWCNTs are doped by the encapsulated WO3 and W nanowires. Tangential band shift in Raman spectra revealed the charge transfer between the nanowires and carbon nanotubes.

Layered tungsten disulfide nanostructures are of both fundamental and technological interest. The widths of currently synthesized WS2 ribbons are in the microscale. By using single-walled carbon nanotubes and double-walled carbon nanotubes as templates, we fabricate WS2 nanoribbons with smooth zigzag edges and uniform widths down to 1–3 nm and layer numbers down to 1–3, dependent on the nanotube diameter. Although bulk WS2 is a nonmagnetic semiconductor, the ultra-narrow free-standing zigzag-edged WS2 nanoribbons turn out to be magnetic or nonmagnetic metals depending on the edge passivation way according to our first-principles calculations, whereas the ultra-narrow armchair-edged WS2 nanoribbons remain nonmagnetic semiconductors with a narrow gap.

High purity single walled carbon nanotubes (SWCNTs) were prepared from arc discharge produced cloth-like soot by a new purification strategy, in which liquid oxidation and steam oxidation were combined with a freeze-drying process to remove the metallic and carbonaceous impurities. The process gives a product of >98% purity, which is acquired from a gram-scale dirty raw soot with an overall yield of ∼75% of the SWCNTs. The purity of the samples was characterized by thermogravimetric analysis, scanning and transmission electron microscopy, Raman and Vis–NIR spectroscopy, and magnetometry. A highly pure SWCNT sample with relative purity of 170.4% and I G / I D value of 78.92 is achieved. Experiments showed that HNO 3 /HCl refluxing combined with freeze-drying is the key process that renders the crude SWCNTs hydrophilic with a large surface area, and thus remarkably increases the efficiency of the steam treatment to remove most of the carbonaceous impurities.