Search

The high surface area and electrical conductivity of few-layered graphene would make it an ideal catalyst support and electrode in fuel cells apart from its susceptibility to oxidative corrosion. Here we report the single-step, bottom-up synthesis of oxidation-resistant boron-doped graphene and show its increased stability in the aggressive electrochemical environment of intermediate temperature solid acid fuel cells (SAFCs). Boron was shown to alter the growth mode of single walled carbon nanohorns by laser vaporization to produce high yields of thin ( 140 °C, with large fractions of multilayered B-GLFs surviving 10 °C/min ramps to 1000 °C. These B-GLFs provided a stable Pt catalyst support and electrode over 40 h operation in SAFCs with cesium dihydrogen phosphate electrolyte operating at 250 °C, as opposed to undoped GLFs or SWCNHs which were nearly completely consumed. The facile synthesis and oxidation-resistant properties of boron-doped GLF appear promising for graphene applications in oxidizing environments.

Pt-based catalysts supported onto various carbon nanotubes (CNTs) and carbon black Vulcan XC-72 have been studied in this work. The samples have been prepared via electrochemical dispersion technique. The carbon nanotubes exhibit the mesoporous morphology with the pore size of 5—30 nm, while Vulcan XC-72 support exhibits a microporous structure. The agglomeration of Pt particles (5—7 nm) is found to be more extended at the carbon nanotubes compared to the carbon black. The examination of the synthesized catalysts in a catalytic membrane electrode assembly layer reveals that CNTs favor a power density higher than in the carbon black support owing to a more suitable porous structure of the catalyst layer. Moreover, the maximum characteristics of membrane electrode assembly are obtained for few-walled carbon nanotubes with a broad carbon having size distribution.

Single-walled carbon nanohorns have received great interest for their unique properties and diverse potential applications. Herein, we demonstrated the feasibility of a single-walled carbon nanohorns incorporated poly(styrene-divinylbenzene) monolith as the stationary phase for capillary electrochromatography, which was prepared by one-step in situ copolymerization. Single-walled carbon nanohorns were dispersed in styrene to give a stable and homogeneous suspension. The monolithic column gave effective separation for a wide range of aromatic compounds, which was based on hydrophobicity and π–π electrostatic stacking of single-walled carbon nanohorns. The precisions of migration time and peak area were variable in the ranges of 1.4–1.9% for intraday trials and 1.7–3.5% for interday trials, and 3.2–6.7% for intraday trials and 4.1–7.4% for interday trials, and 3.6–7.2% for inter-column trials and 5.2–21.3% for inter-column trials, respectively, indicating the good reproducibility of single-walled carbon nanohorns embedded monolithic columns. This article is protected by copyright. All rights reserved

This report deals with a simple and efficient method to develop hybrid carbon nanoparticles (Nps) employing Multi-walled carbon nanotubes (MWCNTs) and Fullerene nps. Fullerene nps were self-assembled via Ultrasonicated Liquid-Liquid Precipitation. Surface treated MWCNTs were entangled with fullerene nps during the process of assembling of the fullerene nps. Fullerene nps are formed by reaction between two solutions, one is the saturated solution which contains dissolved fullerene and other solution is a rough alcohol. This reaction increases the concentration of carbon in the solution and leads to super saturate hence self-assembling into nanoparticles. The obtained hybrid nanoparticles sizes were in the range of 100 nm to 300 nm with entangled mwcnts and were confirmed by characterization using SEM, Raman, UV-Vis, XRD, and DLS.

A copolymer was prepared from glycidyl methacrylate, ethylene glycol dimethacrylate and oxidized single-walled carbon nanohorns via photo-polymerization and used in spin columns for the extraction of nonsteroidal anti-inflammatory drugs (NSAIDs) from human urine samples. All microextraction procedures (loading, washing and elution) can be performed by centrifugation. The hybrid monolithic polymers were characterized by scanning electron microscopy and nitrogen intrusion porosimetry. Following elution with methanol, the NSAIDs (naproxen, fenbufen, flurbiprofen, and ibuprofen) were quantified by reversed-phase HPLC with UV detection. The detection limits varied between 0.1 and 10 μg·L−1, and the precision (relative standard deviation) ranged from 3.5 to 11.8%. Relative recoveries between 81 and 106% were found when analyzing spiked urine samples.

The importance of sensing hydrogen peroxide (H2O2) is due to its ubiquity, being extensively used in industry and also being a biologically relevant side-product of several enzymatic processes. Electrochemical sensing is one of the most robust and simple methods for sensing H2O2 and the discovery of new electroactive materials, particularly at the nanoscale, represents a very hot topic of research. Here, we prove that upon appropriate integration of oxidized single-walled carbon nanohorns (ox-SWCNHs) into a per se moderate H2O2 sensor such as cerium dioxide (CeO2), the sensitivity toward H2O2 is enhanced by almost two orders of magnitude (from 0.4 to 160 μA cm−2 mM−1), on par with that of state-of-the-art metal or metal oxide-based sensors. The modified electrode is also very stable (82% response after 2 weeks of continuous use) and the results highly reproducible. The developed nanohybrid ox-SWCNHs@CeO2, characterized fully and whose average size is about 70 nm as measured by both TEM and AFM, was also tested in real case studies such as washing liquids and milk and was confirmed to be a robust and highly selective material, being not affected neither by the presence of complex matrices, nor by interferents in several organic substrates. The high recovery confirmed the excellent specificity and flexibility of this new electrocatalytic material. Fil: Bracamonte, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. University of Trieste; Italia Fil: Melchionna, Michele. University of Trieste; Italia Fil: Giuliani, Angela. University of Trieste; Italia Fil: Nasi, Lucía. CNR-IMEM Institute; Italia Fil: Tavagnacco, Claudio. University of Trieste; Italia Fil: Prato, Maurizio. University of Trieste; Italia. Carbon Nanobiotechnology Laboratory; España. BasqueFdnSci; España Fil: Fornasiero, Paolo. University of Trieste; Italia

Whereas vertically aligned carbon nanotubes (VACNTs) typically show a promising adsorption behavior at high pressures, carbon nanohorns (CNHs) exhibit superior gas adsorption properties in the low pressure regime due to their inherent microporosity. These adsorption characteristics are further enhanced when both materials are opened at their tips. The so prepared composite material allows one to investigate the effect of physical entrapment of CO2 molecules within the specific adsorption sites of VACNTs composed of opened double walled carbon nanotubes (CNTs) and in specific adsorption sites created by spherically aggregated opened single walled carbon nanohorns. Combining 50 wt% of tip opened CNTs with tip opened CNHs increases the CO2 adsorption capacity of this material by ∼24% at 30 bar and 298 K compared to opened CNHs alone.

Efforts in the broad field of dye-sensitized solar cells (DSSC) are governed by four key challenges: i) the development of photoelectrodes with high charge injection yields and charge collection efficiencies, ii) the development of low-cost buffer layers, which effectively reduce the back reaction of electrons from the transparent conductive oxide (TCO) to the electrolyte, iii) the design of platinum-free counter electrodes (CE), which feature good electrolyte regeneration yields, and iv) the implementation of (quasi) solid-state and iodine-free electrolytes featuring excellent ionic diffusion and conductivity. The introduction of nanocarbons into each component of DSSCs has emerged as a promising strategy to tackle all the aforementioned challenges. Leading examples of nanocarbons are graphene, carbon black (CB), multi-walled carbon nanotubes (MWCNT), and single-walled carbon nanotubes (SWCNT). Here, we focus on single-walled carbon nanohorns (SWCNH), which were successfully integrated into each of the aforementioned parts of DSSCs.

Boron- and nitrogen-codoped single walled carbon nanohorns (BN-SWCNHs) were prepared by CO 2 laser ablation of a boron-containing carbon target under nitrogen atmosphere. The structures were spherical SWCNH aggregates containing many graphite-like thin sheets (GLSs), which was different from general SWCNHs. X-ray photoelectron spectra indicated that the doped quantities of boron and nitrogen were about 1.2 and 1.0 at.%, respectively. The boron and nitrogen atoms were implanted partially as the BN bonding in a graphene lattice, although they were also implanted individually as three-fold coordinated sp 2 bonding. The boron-doped GLSs were preferentially prepared by CO 2 laser ablation of a boron-containing carbon target under argon atmospheres. As a result, we found that the boron accelerated the formation of GLSs. The simple CO 2 laser ablation method will be useful for heteroatoms doping into carbon nanohorns.

A novel phosphomolybdic acid/single-walled carbon nanohorn based amperometric sensing platform was successfully constructed for determination of glucose. Single-walled carbon nanohorn acted as an active matrix and was used to immobilize phosphomolybdic acid. As-prepared phosphomolybdic acid/single-walled carbon nanohorn composite was characterized by SEM, EDX and XRD. Electrochemical behaviors of modified electrodes were characterized by cyclic voltammetry and chronoamperometry. Electrochemical investigations of phosphomolybdic acid/single-walled carbon nanohorn electrode showed three well-defined pairs of redox peaks and rapid electron transfer between electrode and electrolyte. Excellent electrocatalytic performance was obtained due to the synergistic effect of phosphomolybdic acid and single-walled carbon nanohorn. It was concluded that the linear amperometric response to glucose was achieved in the concentration range of 0.035 mM to 4.0 mM, and the detection limit was calculated as 2.4 μM. Moreover, as-prepared phosphomolybdic acid/single-walled carbon nanohorn electrode exhibited prominent selectivity, stability and reproducibility, making it a promising tool for sensitive non-enzymatic determination of glucose.

A single-walled carbon nanohorn (SWCNH) has been used to construct a molecularly imprinted electrochemical sensor for the first time. Kanamycin, a widely used aminoglycoside antibiotic, is used as a representative analyte to test the detection strategy. The kanamycin sensor was constructed by the electropolymerization of a molecularly imprinted poly-o-phenylenediamine film on a SWCNH modified glassy carbon electrode. The sensor was investigated in the presence or absence of kanamycin by cyclic voltammetry to verify the changes in the redox peak currents of K3Fe(CN)6. The sensor exhibits a linear range of 0.1-50 μM with a detection limit of 0.1 μM. It also shows high recognition ability, indicating that the SWCNH-based molecularly imprinted sensor is promising.

The extremely large surface areas as well as connecting nanopores of single-walled carbon nanohorn (SWCNH) aggregates have been tested, for the first time to the best of our knowledge, as metal-free, stable and cheap electrocatalysts for heterogeneous electron transfer reactions involving inorganic redox couples, including f-block elements such as actinides. From systematic studies of heterogeneous electron transfer reactions, the electrochemically reversible outer-sphere heterogeneous surface insensitive electron transfer reaction involving [Ru(NH3)6]3+/[Ru(NH3)6]2+ and the electrochemically near-to-reversible inner-sphere heterogeneous surface sensitive electron transfer reaction involving [Fe(CN)6]3−/[Fe(CN)6]4− on oxygenated SWCNHs (i.e., o-SWCNHs) have been compared to heterogeneous electron transfer involving the quasi-reversible [U(VI)O2(CO3)3]4−/[U(V)O2(CO3)3]5− redox reaction on o-SWCNHs. It was evident that the oxygen containing functional groups of o-SWCNH could catalyze the electron transfer process between uranium species in solution and the working electrode happened by following surface-sensitive inner-sphere electron transfer mechanism. Furthermore, the electrochemical stability, repeatability and reproducibility of the o-SWCNH modified glassy carbon electrode were found to be analytically acceptable for studying the electrochemistry of uranium in alkaline solutions with high ionic strength.

Ochratoxin A (OTA), is one of the most commonly found mycotoxins in food. It is primarily produced by Aspergillus ochraceus and Penicillium verrucosum. OTA can causes serious damages to liver and kidney, increases the teratogenicity, and has been considered as a potential carcinogen (group 2 B). In this study, we demonstrated a new detection system for the detection of OTA using fluorescence biosensing according to an anti-OTA aptamer and fluorescence quencher using single-walled carbon nanohorns (SWCNHs). In the presence of OTA, the OTA-specific aptamer underwent the conformation change from a random coil to an antiparallel G-quadruplex. The latter one was resistant to being adsorbed onto SWCNHs, leading to the pertection of the fluorescence of SYBR Gold. As a result, the remained fluorescent intensities correlated with the concentrations of OTA. The detection limit of OTA was 2.3 ng/ml, meanwhile the linear detection range was 5–500 ng/ml, with a satisfactory linear correlation (R2 = 0.992) of the fluorescence intensity and the logarithm of OTA concentrations. The aptasensor was subjected to quantify the concentration of OTA in red wine samples. As a result, this label-free aptasensor was suitable for the test of OTA in food samples.

The results of in vitro studies of single-walled carbon nanohorn (SWCNH) oxidized materials’ cytotoxicity obtained by the cell membrane integrity (Neutral Red Uptake (NRU)) and metabolic activity (by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)) on A549 and human dermal fibroblasts (HDF) cell lines are presented. We also present hemocompatibility studies on human and porcine blood, and an erythrocyte concentrate to prove that the obtained samples will not interfere with blood components. Characterization of the materials is supplemented by ζ-potential measurements, Transmission Electron Microscope (TEM) imaging, and thermogravimetric studies (TG). The presented results show the correlation between the specific surface area of materials and the platelet aggregation, when the ID/IG ratio determined from Raman spectra correlates with hemoglobin release from the erythrocytes (in whole blood testing). A plausible mechanism explaining the observed correlations is given. The cytotoxicity and hemocompatibility studies prove that the studied materials are acceptable for use in biomedical applications, especially a sample SWCNH-ox-1.5 with the best application potential.

To store more energy in limited spaces, the volumetric performance of energy storage devices used in electric vehicles and portable electronics has attracted more research attention than their gravimetric performance. Herein, we describe the preparation of N/O co-doped single-walled carbon nanohorns (SWCNH) using chemical vapor deposition with pyridine followed by acid treatment to obtain a supercapacitor electrode material with high specific volumetric capacitance. The synthesized N/O co-doped SWCNH (N and O contents of 6.1 and 9.1 at%, respectively) electrode had a higher bulk density (1.05 g cm−3) than that of the pristine SWCNH electrode (0.86 g cm−3). Moreover, the N/O co-doped SWCNH supercapacitor electrode exhibited drastically increased specific volumetric, gravimetric, and areal capacitances (123 F cm−3, 117 F g−1, and 91.4 μF cm−2, respectively) in 1 M H2SO4 electrolyte, compared with those of a pristine SWCNH electrode (36 F cm−3, 42 F g−1, and 11.4 μF cm−2, respectively). The superior electrochemical performances are associated with enhanced pseudocapacitive contribution and high bulk density of electrode upon N/O co-doping. The simple method described herein for producing SWCNH electrodes with high bulk density and high specific volumetric capacitance should contribute to the development of supercapacitors with high volumetric performance.

In this study, we report the effective thermal conductivity and rheological behavior of ethylene glycol with single-walled carbon nanohorn inclusions. The thermal conductivity and viscosity was fou...

Catalyst-free, high-yield (kilogram-scale) and high-purity (>95%) synthesis of dahlia flower and “bud-like” single-walled carbon nanohorns (SWCNHs) has been achieved via DC arc discharge under high pressures of Ar gas up to 0.35 MPa. In contrast, the mean size (100 nm) of SWCNH particle was twice as large as the counterpart in the literature via arc discharge. A new growth mechanism is proposed rationally to explain the mass production of SWCNHs under positive pressures, the growth mechanisms of SWCNHs rely mainly on the concentration of carbon clusters, rather than the temperature gradient of arc zone.

In this study, Titania (TiO 2 ) based composites reinforced with 2 wt% of various carbon nanomaterials were prepared using spark plasma sintering (SPS). Prior to SPS, the samples were ball milled. The reinforcements used in the composites were graphene nanoplatelets (GNP), carbon nanotubes (CNT) and single walled carbon nanohorns (SWNH). The ball milled powders and SPS compacts were characterized using various techniques. Mechanical and photocatalytic properties of the SPS composites were evaluated and compared for different nano-carbon reinforced TiO 2 composites. X-ray diffraction and Raman spectroscopy studies confirmed that the milled powders comprised of Anatase phase which transformed into Rutile phase during SPS. Nano transformation twins were observed in Rutile grains. Fractured surfaces showed that the reinforcements were well bonded with the TiO 2 grains and the SWNH reinforcement resulted in comparatively finer grain size. Nanoindentation studies showed that the hardness and elastic modulus of GNP reinforced composites was 78% and 30% respectively higher compared to TiO 2 matrix. The hardness and modulus of the CNT reinforced TiO 2 increased by 22% and 5.4% respectively while that of the SWNH reinforced TiO 2 increased by 11% and 23% respectively. GNP and CNT reinforced TiO 2 exhibited superior photocatalytic activity for the degradation of methylene blue dye compared to pure TiO 2 .

A dual-signalling electrochemical approach has been developed towards aconitine based on competitive host-guest interaction by selecting methylene blue (MB) and p-sulfonated calix[8]arene functionalized single-walled carbon nanohorns (SCX8-SWCNHs) as the "reporter pair". Upon the presence of aconitine to the performed SCX8-SWCNHs·MB complex, the MB molecules are displaced by aconitine. This results in a decreased oxidation peak current of MB and the appearance of an oxidation peak of aconitine, and the changes of these signals correlate linearly with the concentration of aconitine. A linear response range of 1.00-10.00μM for aconitine with a low detection limit of 0.18μM (S/N=3) was obtained by using the proposed method. This method could be successfully utilized to detect aconitine in serum samples. This dual-signalling sensor can provide more sensitive target recognition and will have important applications in the sensitive and selective electrochemical detection of aconitine.

The effect of different surfactants on the removal efficiency of wiping surfaces contaminated with single walled carbon nanohorns (SWCNHs) was studied. To this end, sodium dodecylbenzenesulfonate (SDBS) and sodium dodecyl sulfate (SDS) surfactants were used, and their removal efficiencies with water only and with cleaning with a dry wipe were compared. The surfactant concentrations and wipe pressure during the wiping process were varied, and significant effects on removal efficiency were found. In addition, the results were compared with those obtained with single-walled carbon nanotubes (SWCNTs) and multi-walled CNTs (MWCNTs) and the differences among these nanostructures were reported. The results suggest that SDS and SDBS are good candidates for removal of SWCNHs deposited on silicon wafers with SDS removal efficiencies capable of exceeding 90%. In addition, the results show that there is an optimum wiping pressure and surfactant concentration with the highest removal efficiency. A direct relationship was also found between wipe saturation and removal efficiency of SWCNHs deposited on silicon substrates. The differences between individual nano structures were perceptible in spite of following similar broad trends; for instance, SWCNH contaminated surfaces in general proved more difficult to clean than surfaces contaminated with the other nanostructures.

Adsorption of polyethylene glycol conjugated phospholipids with various PEG chain length (DSPE-PEG5000, 2000, 750) onto single-walled carbon nanohorns (SWCNH), a type of graphene nano-tubule, in aqueous solution was investigated by means of high-resolution magic angle spinning (HRMAS) 1H NMR. Peak integral ratio of PEG chains and alkyl chains of DSPE-PEGs in the NMR spectra linearly decreased to zero with the increase of SWCNH quantity, indicating that the adsorption of DSPE-PEGs on SWCNH was virtually irreversible. The area of SWCNH surface allocated to the individual DSPE-PEG5000, 2000, 750 molecule were estimated to be 7.06, 5.18, and 4.45 nm2, respectively. Coverages of the alkyl chains on the surface area of SWCNH were about 28%, 39% for DSPE-PEG5000, 2000 and 46% for DSPE-PEG750, suggesting single layer adsorption. We presumed that the electrostatic repulsion may prevent DSPE-PEGs from multiple layer and keep away neighbouring DSPE-PEGs on the surface. According to the molecular areas of the DSPE-PEGs, PEG5000 and 2000 chains were considered to be in brush-regimes, while PEG750 was considered to be in mushroom regime on the SWCNH surface.

The hydrogenated and non-hydrogenated single walled carbon nanohorns (SWCNH) are studied. SWCNH with the density of 0.75 g cm−3 showed the maximum differential hydrogen uptake capacities of 1.4 wt.% at 77 K. The temperature Fourier transform infrared (FT-IR) spectra for non-hydrogenated and hydrogenated samples revealed differences in the vibrational mode bands. The hydrogenation of SWCNH hardly affected the positron lifetime spectra. Only small shift of pattern was observed in the X-ray diffraction measurements at 300 K. Obtained results were compared to these for other carbon nanomaterials.

The unique water transport properties in nanospaces are essential for control of various chemical reactions, biochemical activities, and electrochemical systems. Fast water transport has been observed in one-dimensional nanospaces. However, water transport via zero-dimensional nanospaces has not yet been observed. Zero-dimensional nanospaces were obtained by extremely small and thin gate (zero-dimensional gate) insertion on graphene walls of single-walled carbon nanohorns. The water transport properties were examined by water vapor loading and release via the zero-dimensional gates, and molecular dynamics simulation. Although relatively large gates provided considerable adsorption hysteresis by long-term equilibrium, water vapor loading and release via the extremely small gates showed consecutive water loading and release. The molecular dynamics simulation showed consecutive water transport via the gates, probably because of lower energy barriers to water transport in the vicinity of the gates. The zero-d...

A novel electrochemical sensor was developed by electrodepositing gold nanoparticles on the single-walled carbon nanohorns modified glassy carbon electrode. We used the prepared sensor to determine hydrazine for the first time. The results show that the modified electrode has good electrocatalytic activity toward the oxidation of hydrazine. Under the optimized conditions, two wide linear segments were observed between the catalytic currents and the concentration of hydrazine within the range of 0.005–3.345 mM with a detection limit of 1.1 μM (s/n = 3). The diffusion coefficient of hydrazine was also estimated using chronoamperometry. Additionally, the sensor showed excellent sensitivity, selectivity, and reproducibility properties.

Cytomegalovirus is typically associated with immunocompromised hosts, pregnant women and transplant patients, who require a timely diagnosis. In this work, a sensitive and highly specific electrochemical amplification immunosensor was established for detecting Cytomegalovirus pp65 antigen based on Pt-PdNPs@SWCNHs with horseradish peroxidase (HRP) as a signal enhancer and thionine as a signal probe. First, Pt nanoparticle (PtNP) and Pd nanoparticle (PdNP) functionalized single-walled carbon nanohorn (SWCNH) nanocomposites, i.e. Pt-PdNPs@SWCNHs, was used as a carrier for immobilization of antibody through the Pt-N bond and the Pd-N bond. Next, HRP was used to block the rest of the binding-sites. Signal amplification was obtained by the cooperative catalytic activities of Pt-PdNPs and HRP to H2O2. SWCNHs loaded with a large amount of Pt-PdNPs further amplified the signal due to the excellent surface area. The fabricated immunosensor was used to detect different concentrations of Cytomegalovirus pp65 antigen under optimized conditions. The tests showed a linear range from 0.1 to 80 ng mL−1 with a low detection limit of 30 pg mL−1, and exhibited excellent selectivity, stability and reproducibility. Therefore, this project presented a potential approach for the early diagnosis of Cytomegalovirus infection in clinical trials.

Two kinds of luminescent nanoprobes were developed for Pb2+ detection based on luminescence resonance energy transfer (LRET) by using sodium citrate functionalized upconversion nanoparticles (Cit-UCNPs) as the energy donor and single-walled carbon nanohorns (SWCNHs) or graphene oxide (GO) as the energy acceptor. A Pb2+ aptamer 5′-NH2-(CH2)6-GGGTGGGTGGGTGGGT-3′ (denoted as pDNA) sequence was assembled with Cit-UCNPs to form the Cit-UCNPs–pDNA. By using the SWCNHs (or GO) as matrix, the final Cit-UCNPs–pDNA–SWCNHs (or Cit-UCNPs–pDNA–GO) nanoprobe can be obtained, in which the LRET process happened and the upconversion luminescence of the probe was quenched. With the addition of Pb2+, a stable G-quadruplex–Pb2+ complex was formed, which results in the separation between Cit-UCNPs–pDNA nanoparticles and SWCNHs (or GO) and the recovery of the upconversion luminescence. The two turn-on luminescence probes could detect Pb2+ ions from amongst other ions with high sensitivity and selectivity in aqueous solution. To the best of our knowledge, a nanoprobe for the detection of Pb2+ ions based on LRET between UCNPs and SWCNHs (or GO) has not been reported in the literature to date. This work demonstrates a simple yet powerful sensing strategy, which may open up potential perspectives for environmental monitoring applications.

The present research reports a smart multifunctional oxidized single-wall carbon nanohorns (oxSWNHs) drug delivery system (DDS) which could enhance the anti-tumor effect of methotrexate (MTX). In this DDS (MTX@oxSWNHs–PEG–Tf), oxSWNHs loaded MTX was wrapped with DSPE–PEG–NH2 to prolong blood circulation half-life and target tumors with the help of covalent grafting of transferrin (Tf). The obtained DDS was characterized by scanning electron microscopy, UV-vis spectrophotometry, size distribution analysis and Z-potential measurement. Cell uptake studies on MAD-MB-231 and HepG2 cell lines confirmed that the MTX@oxSWNHs–PEG–Tf exerted higher antitumor activity compared with free drug or non-targeted counterpart. The in vivo antitumor efficacy of MTX@oxSWNHs–PEG–Tf was much stronger than that of the free drug group by comparing the change of tumor volume and weight. Toxicity studies showed little perceivable cardiotoxicity, hepatotoxicity and pulmonary toxicity of MTX@oxSWNHs–PEG–Tf, indicating that this new tumor-targeting DDS significantly enhanced the anti-tumor effect of MTX and decreased its side effects.

A new luminescence “Turn-On” nanoplatform based on luminescence resonance energy transfer (LRET) from sodium citrate functionalized upconversion nanoparticles (Cit-UCNPs, energy donor) to single-walled carbon nanohorns (SWCNHs, energy acceptor) was prepared for sensitive detection of acute promyelocytic leukemia (APL). In the presence of the target DNA, a PML/RARα fusion gene of APL, the π–π stacking interaction between the energy donor Cit-UCNPs and energy acceptor SWCNHs weakened and their distance enlarged. Therefore, the luminescence of Cit-UCNPs would be recovered (turn on) due to the inhibition of the LRET process. Based on this fact, a sensitive method was developed for the fluorescence turn on detection of ALP with a detection limit as low as 0.28 nM. To the best of our knowledge, this is the first time that upconversion nanoparticles and single-walled carbon nanohorns were used as a donor–acceptor pair to detect PML/RARα fusion gene sequences through a LRET process.

This short communication reveals that the magnetic and porous properties of Fe-included single-walled carbon nanohorns (Fe-SWCNHs) can be improved via oxidation in water by injection of ozone at room temperature. Fe in Fe-SWCNHs is converted to ferrimagnetic Fe3O4 without producing paramagnetic Fe2O3 by this method. The specific surface area on the basis of the specimen mass can be doubled by this treatment together with significant increase of micro and meso pore volumes. Their magnetic susceptibility which is a determinant factor to magnetically drive the products in fluid can be increased by this ozone oxidation. The enhancement effects on the porous and magnetic properties of Fe-SWCNHs should be preferable to develop catalyst support or adsorption media which can be magnetically handled. The method proposed here is extremely safe and environmentally benign.

A cobalt-doped graphitic carbon nitride (g-C3N4) polymer was supported on surface-modified single-walled carbon nanohorns (SWCNHs) to produce a new Co-g-C3N4 catalyst for the oxygen reduction reaction (ORR). X-ray photoelectron spectroscopy results show that Co–N bonds are formed and that strong electronic coupling occurs between the SWCNHs and Co-g-C3N4. The as-fabricated catalysts exhibit reasonable ORR activity, high selectivity, and outstanding electrochemical stability in alkaline media. These results are attributed to the large number of stable Co–Nx active sites, high percentage of pyridinic N and rapid mass transport on the “Dahlia flower”-like SWCNHs surface. The fabricated Co-g-C3N4/SWCNHs catalyst has potential for use as a non-precious metal cathodic catalyst in fuel cell applications.

Single-walled carbon nanohorns (SWCNHs), a type of tapered carbon nanomaterials, are generally prepared by laser ablation method, arc method, and Joule heating method without the addition of metal catalysts, which makes them pure and environmentally friendly. The obtained aggregates of SWCNHs mainly have three different types of structure, dahlia-like, bud-like, and seed-like. Over the past few decades, they have been widely used in the fields of energy, medicine, chemistry, and sensing. The SWCNHs-based sensors have shown high sensitivity, rapid response, and excellent stability, which are mainly attributed to the excellent electrical conductivity, large electrochemical window, large specific surface area, and mechanical strength of SWCNHs. In this review, we systematically summarizes the structures, synthesis methods, and sensing applications of SWCNHs, including electrochemical sensors, photoelectrochemical sensors, electrochemiluminescence sensors, fluorescent sensors, and resistive sensors. Moreover, the development prospects of SWCNHs in this field are also discussed.

Hybrid electrocatalysts made from ultrafine Pd nanoparticles strongly coupled on single-wall carbon nanohorns (Pd/CNH) are prepared via a facile and scalable approach. Benefiting from the unique interconnected open-pore microstructure of CNHs as well as the numerous exposed Pd active sites, such an architectural design can substantially increase the Pd utilization efficiency and thereby reduce the overall dosage of metal Pd. Strikingly, the newly-developed Pd/CNH hybrid with an ultra-low Pd loading amount of 5.0 wt% exhibits high forward anodic peak current densities of up to 1420.4 and 1910.6 mA mg−1 toward formic acid and methanol oxidation, respectively, both of which are significantly superior to those of commercial 20.0 wt% Pd/carbon black catalyst. This study may offer an economic option and a new vision for the development of the next-generation low-cost fuel cell anode catalysts.

The combination of biocompatibility and unique surface properties has led to the extensive study of the biological applications of carbon nanomaterials. We are interested in the application of single walled carbon nanohorns (CNH) for the development of tools for cellular imaging, diagnostics and therapeutics. CNHs are made up of sp2 conical shaped postulates, with diameters of 2–5 nm and lengths of 40–50 nm, assembled into robust bud-like spherical aggregates of between 80 and 100 nm. The key advantage of these materials is their low toxicity, high surface area, and ease of functionalisation.1,2 In this presentation results from our recent work on the use of CNHs for enhanced biosensing of glutamate,3 to study of the cellular interactions of fluorescently labelled CNH systems and their use of CNHs to delivery photodynamic therapy agents to cells will be presented. The poor cellular uptake of many porphyrins is a barrier to their application in phototherapeutic applications,4 biocompatible CNH carriers offer a means to overcome this. A spectroscopic study of the binding interactions of the PtTMPyP4 cationic porphyrin with oxidised carbon nanohorns through non-covalent, electrostatic interactions revealed a high a loading of 200 wgt%. Brightfield microscopy demonstrated the efficacy of sparsely loaded Porphyrin-CNH constructs to be internalised within HeLa cells, which were found to undergo rapid cell death upon visible light excitation.5 The ability to image processes in cells and track the interaction and efficacy of nanomaterial cellular uptake is of great interest. The use of an ON/OFF fluorophore whose emission is triggered upon cellular uptake will be described as a means to monitor time dependent uptake by live-imaging and also to report on the influence of functionalisation on the extent of cellular aggregation.6 Finally, some more recent results on tracking the destination of carbon nanohorns in cells will be reported. 1. Iijima, M. Yudasaka, R. Yamada, S. Bandow, K. Suenaga, F. Kokai, K. Takahashi, Chem. Phys. Lett. 1999, 309, 165−170.S. 2. Zhuab, G. Xu, Nanoscale, 2010, 2, 2538–2549. 3. R. Ford, S. J. Devereux, S. J. Quinn, R. D. O'Neill, Analyst, 2019, 144, 5299-5307 4. A. Rajora, J.W.H. Lou and G. Zheng, Chem. Soc. Rev., 2017, 46, 6433 – 6469. 5. J. Devereux, M. Massaro, A. Barker, D. T. Hinds, B. Hifni, J. C. Simpson and S. J. Quinn, J. Mater. Chem. B, 2019, 7, 3670–3678. 6. S. J. Devereux, S. Cheung, H. C. Daly, D. F. O'Shea and S J. Quinn, Chem. Eur. J., 2018, 24, 14162–14170.

Recently, two-dimensional tungsten disulfide (WS2) has attracted attention as a next generation thermoelectric material due to a favorable Seebeck coefficient. However, its thermoelectric efficiency still needs to be improved due to the intrinsically low electrical conductivity of WS2. In the present study, thermoelectric properties of WS2 hybridized with highly conductive single-walled carbon nanohorns (SWCNHs) were investigated. The WS2/SWCNH nanocomposites were fabricated by annealing the mixture of WS2 and SWCNHs using a high-frequency induction heated sintering (HFIHS) system. By adding SWCNHs to WS2, the nanocomposites exhibited increased electrical conductivity and a slightly decreased Seebeck coefficient with the content of SWCNHs. Hence, the maximum power factor of 128.41 &mu, W/mK2 was achieved for WS2/SWCNHs with 0.1 wt.% SWCNHs at 780 K, resulting in a significantly improved thermoelectric figure of merit (zT) value of 0.027 compared to that of pristine WS2 with zT 0.017.

A novel competitive electrochemical immunosensor based on Au nanodendrites (Au NDs)/silver nanoparticles (Ag NPs) @single-walled carbon nanohorns (SWCNHs) was established for sensitive determination of sulphonamides (SAs) in aquatic environments. The indirectly competitive binding system of the approach was composed of coating antigen that coated on Au NDs/glass carbon electrode (GCE), the target and primary antibody (Ab1). When Ab2@Ag NPs@SWCNHs was captured by coating antigen (Cag)- Ab1 complex, massive Ag+ will be released from electrode in the presence nitric acid (HNO3), consequently, the generated Ag+ will significantly amplify the electrochemical signal, which would be recorded by the linear sweep voltametry (LSV). Meanwhile, the used three-dimensional Au nanodendrites (Au NDs) could increase the conductivity of the electrode and the size of the active surface area to improve the antigen-loading. Under the optimal conditions, the immunosensor showed a good linear relationship for sulfamethazine (SMZ)ranged in 0.33–63.81 ng/mL with a detection limit of 0.12 ng/mL (LOD, based on 90% inhibition). In addition, the proposed approach exhibited satisfactory accuracy and precision (recoveries, 79.25–119.25%; CV, 2.14–9.58%), it can be applied for rapid analysis of the trace pollutants from environmental waters.

Direct conversion of carbon dioxide to formic acid at thermodynamic equilibrium is an advantage of enzymatic catalysis, hardly replicated by synthetic analogs, but of high priority for carbon-neutral energy schemes. The bio-mimetic potential of totally inorganic Pd@TiO2 nanoparticles is envisioned herein in combination with Single Walled Carbon NanoHorns (SWCNHs). The high surface nano-carbon entanglement templates a wide distribution of "hard-soft" bimetallic sites where the small Pd nanoparticles (1.5 nm) are shielded within the TiO2 phase (Pd@TiO2), while being electrically wired to the electrode by the nanocarbon support. This hybrid electrocatalyst activates CO2 reduction to formic acid at near zero overpotential in the aqueous phase (onset potential at E < -0.05 V vs. RHE, pH = 7.4), while being able to evolve hydrogen via sequential formic acid dehydrogenation. The net result hints at a unique CO2 "circular catalysis" where formic acid versus H2 selectivity is addressable by flow-reactor technology. Fil: Melchionna, Michele. Università degli Studi di Trieste; Italia Fil: Bracamonte, Maria Victoria. Università degli Studi di Trieste; Italia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Giuliani, Angela. Università degli Studi di Trieste; Italia Fil: Nasi, Lucia. Istituto Dei Materiali Per L'elettronica Ed Il Magnetismo; Italia Fil: Montini, Tiziano. Università degli Studi di Trieste; Italia Fil: Tavagnacco, Claudio. Università degli Studi di Trieste; Italia Fil: Bonchio, Marcella. Università di Padova; Italia Fil: Fornasiero, P. Università degli Studi di Trieste; Italia Fil: Prato, Maurizio. Università degli Studi di Trieste; Italia

Single-walled carbon nanohorns (SWNHs) can accumulate in a variety of cell types or tissues and exert biological effects, which have been demonstrated to induce apoptosis in hepatoblastoma cells. However, the role and molecular mechanisms of SWNHs remain unclear. The mitochondrion is an important subcellular structure and may contribute to apoptosis that is induced by SWNHs in hepatoblastoma cells. To address this question, the mitochondrial function of HepG2 or L02 cells that were treated with SWNHs was examined. The results indicated that SWNHs were able to decrease the mitochondrial membrane potential and suppress the activity of the Na+/K+-ATPase. Secondly, HepG2 cells and L02 cells were treated with SWNHs in vivo and in vitro. The expression of mitochondrial-associated proteins [acyl-CoA synthetase short chain family member 1, Bax, cytochrome C (CYT-C), sodium channel epithelial 1α subunit, sirtuin 3 (SIRT3) and voltage-dependent anion channel 1] was analyzed by western blotting and immunohistochemical staining. The results revealed that SWNH treatment was able to alter the expression of multiple mitochondrial apoptotic pathway-associated proteins in HepG2 cells. SWNH treatment was able upregulate the expression of SIRT3, CYT-C and VDAC1 and downregulate the expression of AceCS2, but it had a more stable effect on SIRT3. However, similar findings were not observed in L02 cells. Therefore, the data from the present study indicated that SWNHs might be used as a safe anticancer agent, where it is able to trigger mitochondrial dysfunction-induced apoptosis by upregulating SIRT3 expression in HepG2 cells.

Nitrogen-doped single-walled carbon nanohorns (N-SWCNHs) are porous carbon material characterized by unique horn-shape structures with high surface areas and good conductivity. Moreover, they can be mass-produced (tons/year) using a novel proprietary process technology making them an attractive material for various industrial applications. One of the applications is the encapsulation of sulfur, which turns them as promising conductive host materials for lithium–sulfur batteries. Therefore, we explore for the first time the electrochemical performance of industrially produced N-SWCNHs as a sulfur-encapsulating conductive material. Fabrication of lithium–sulfur cells based on N-SWCNHs with sulfur composite could achieve a remarkable initial gravimetric capacity of 1650 mA h g–1, namely equal to 98.5% of the theoretical capacity (1675 mA h g–1), with an exceptional sulfur content as high as 80% in weight. Using cyclic chronopotentiometry and impedance spectroscopy, we also explored the dissolution mechanism ...

A monolithic solid based solely on single walled carbon nanohorns (SWNHs) was prepared without the need of radical initiators or gelators. The procedure involves the preparation of a wet jelly-like system of pristine SWNHs followed by slow drying (48 h) at 25 C. As a result, a robust and stable porous network was formed due to the interaction between SWNHs not only via - and van der Waals interactions, but also via the formation of carbon bonds similar to those observed within dahlia aggregates. Pristine SWNHs and the SWNH monolith were characterized by several techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser scanning microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen intrusion porosimetry. Taking into account the efficiency of carbon nanoparticles in sorption processes, the potential applicability of the SWNH-monolith in this research field was explored using toluene; m-, p-, and o-xylene; ethylbenzene; and styrene, as target analytes. Detection limits were 0.01 g L�����1 in all cases and the inter-day precision was in the interval 7.4–15.7%. The sorbent performance of the nanostructured monolithic solid was evaluated by extracting the selected compounds from different water samples with recovery values between 81.5% and 116.4%.

With the growth of the global economy and population, the demand for energy is increasing sharply. The development of environmentally a benign and reliable energy supply is very important and urgent. Single-walled carbon nanohorns (SWCNHs), which have a horn-shaped tip at the top of single-walled nanotube, have emerged as exceptionally promising nanomaterials due to their unique physical and chemical properties since 1999. The high purity and thermal stability, combined with microporosity and mesoporosity, high surface area, internal pore accessibility, and multiform functionalization make SWCNHs promising candidates in many applications, such as environment restoration, gas storage, catalyst support or catalyst, electrochemical biosensors, drug carrier systems, magnetic resonance analysis and so on. The aim of this review is to provide a comprehensive overview of SWCNHs in energy applications, including energy conversion and storage. The commonly adopted method to access SWCNHs, their structural modifications, and their basic properties are included, and the emphasis is on their application in different devices such as fuel cells, dye-sensitized solar cells, supercapacitors, Li-ion batteries, Li-S batteries, hydrogen storage, biofuel cells and so forth. Finally, a perspective on SWCNHs’ application in energy is presented.

It was discovered that the specific surface area and magnetic susceptibility of Fe-dispersing single-walled carbon nanohorns (Fe-CNHs) were significantly increased without obvious destruction of CNH structures by oxidation in CO 2 (10%) diluted with N 2 at 1000 °C. As-grown Fe-CNHs synthesized by a submerged arc discharge method had a specific surface area of 184 m 2 /g, and this surface area was raised to 500 m 2 /g by opening of pores upon this oxidation treatment. Under this condition, the carbon-based specific surface area are enhanced from 211 m 2 /g to 863 m 2 /g. Fe nanoparticles dispersing in Fe-CNHs were transformed into ferrimagnetic Fe 3 O 4 nanoparticles without obvious change in their particle sizes and frames of CNHs. The magnetic susceptibility of the Fe-CNHs was increased by this oxidation, suggesting that their magnetic mobility could be improved. The structure of Fe-CNHs was stable against the extended oxidation duration in the CO 2 –N 2 . In contrast to the oxidation in CO 2 –N 2 , the oxidation in air resulted in the transformation of Fe nanoparticles into paramagnetic Fe 2 O 3 , and the excessive oxidation led to destructive loss of CNHs.

We report a simple method for the direct and quantitative determination of dihydronicotinamide adenine dinucleotide (NADH) using a single-walled carbon nanohorn (SWCNH) modified glassy carbon electrode (GCE). The electrochemically activated SWCNH modified GCE (SWCNH/GCE) substantially lowers the overpotential necessary for NADH oxidation compared to the inactivated SWCNH/GCE or bare GCE. We observe a 89-mV shift in the peak potential of NADH from GCE to SWCNH/GCE and another 101-mV shift from inactivated SWCNH/GCE to activated SWCNH/GCE in phosphate buffer (pH 7.0) at a scan rate of 50 mV/s. The activated SWCNH/GCE shows a linear response toward NADH between 1 and 100 μM with the detection limit of 0.2 μM. The activated SWCNH/GCE displays good reproducibility, high sensitivity, and excellent stability. Furthermore, the fabricated electrochemical sensors were used to detect NADH in serum by standard addition method and the recoveries are satisfactory.

The addition of nanoparticles in lubricating oils recently demonstrated to reduce the coefficient of friction and to increase the load-carrying capability of lubricant in coupled surfaces. In this work, different kinds of nanoparticles were tested as additives to engine oil to improve lubrication: copper and titanium oxide nanoparticles and single walled carbon nanohorns (SWCNHs). Two nanoparticle sizes were also tested in case of copper. The tribological properties of these nanofluids were evaluated by Stribeck tests, in order to compare the effect of nanoparticles on friction coefficient and electric contact resistance in different lubrication regimes. Stribeck curves showed that the coefficient of friction was reduced, compared to raw oil, by the action of Cu nanoparticles having 130 nm diameter, leading to a mean decrease of about 17%, and by SWCNHs, with a mean decrease of about 12%. Conversely, no significant changes were detected in presence of Cu nanoparticles having 50 nm diameter or of TiO2. The suspension viscosity and stability were also tested. Wear tests were also carried out, showing a reduction of wear rate up to nearly 50% for Cu nanoparticles (150 nm diameter) and around 30% for SWCNHs. The measurements showed that nanoparticles having size comparable to the mean roughness of coupled surfaces significantly improved the tribological properties of bare oil. An explanation of nanoparticle action is proposed.

Cost-effective synthesis of single walled carbon nanotube (SWCNT) and single walled carbon nanohorn (SWCNH) hybrids, in a single step, by electric arc discharge technique in open air, at lower current densities is reported. The rate of production of the hybrids is 3-5 g/h. The presence of SWCNTs and SWCNHs is confirmed by a transmission electron microscope (TEM). In addition to conventional larger Dahlia-like aggregates of nanohorns, unique nearly-spherical shaped and relatively smaller sized aggregates (mean size ? 25 nm) of nanohorns are formed along with thin bundles (mean diameter ? 5.7 nm) of SWCNTs. � 2015 Elsevier B.V. All rights reserved.

The simultaneous esterification of palmitic acid and transesterification of tributyrin is investigated using a solid acid catalyst newly developed. This catalyst consists of porous single-walled carbon nanohorn (SWCNH) dispersed with Fe/Fe2O3-mixed nanoparticles. The esterfication of palmitic acid is initially catalyzed by this catalyst, and the transesterification of tributyrin can be observed after most of palmitic acid was consumed. Contrary to a general expectation that the addition of a free fatty acid usually has poisonous effect on transesterification of tributyrin, the addition of palmitic acid shows an effect to enhance the yield of methyl butyrate. As one of the reasons, the palmitic acid adsorbed on Fe/Fe2O3 particles placed in the pores of the catalyst may attract tributyrin molecules, and tributyrin concentrated thereon may diffuse to the acidic sites on the catalyst. However, this effect seems to be reduced significantly when the reaction temperature is high.