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In the present study, SWCNH-COOH and SWCNH-TETA were fabricated using single-walled carbon nanohorns (SWCNHs) via carboxylation and grafting with triethylenetetramine (TETA) for uranium (VI) ion [U(VI)] removal. The morpho-structural characterization of as-prepared adsorbing materials was performed by transmission electron microscopy, X-ray diffractometry, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Several parameters including the pH value of the aqueous solutions, contact time, temperature, and U(VI) concentration were used to evaluate the sorption efficiency of SWCNH-COOH and SWCNH-TETA. The Langmuir isotherm model could well represent the as-obtained adsorption isotherms, and the kinetics was successfully modeled by pseudo-second-order kinetics in the adsorption process. The maximum adsorption capacity of SWCNH-TETA was calculated as 333.13 mg/g considering the Langmuir isotherm model. Thermodynamic studies showed that adsorption proved to be a spontaneous endothermic process. Moreover, SWCNH-TETA exhibited excellent recycling performance and selective adsorption of uranium. Furthermore, the possible mechanism was investigated by XPS and density functional theory calculations, indicating that the excellent adsorption was attributed to the cooperation capability between uranium ions and nitrogen atoms in SWCNH-TETA. This efficient approach can provide a strategy for developing high-performance adsorbents for U(VI) removal from wastewater.

Photochromic molecules derived from bioresources and their hybrids with various carbon nanomaterials always resulted in devices with outstanding performance. Among different carbon nanomaterials su...

Recently, substantial focus has made in the development of cost effective Pt-free dye sensitized solar cells (DSSCs). In this article we report a potential, Pt-free, carbon based nanocomposite as counter electrode catalyst for dye sensitized solar cells. Graphene oxide (GO) was made into reduced graphene oxide (SSrGO) by irradiating with light (Xe source). Suspension of SSrGO in DMF was spray coated onto fluorine doped tin oxide (FTO) coated glass substrate, followed by spray coat of single walled carbon nanohorns (SWCNH) suspension in DMF. SSrGO and SWCNH coated FTO glass substrate was investigated as an effective Pt-free composite counter electrode (CE) for DSSC and also showed the comparable catalytic activity with Pt. The test cell reveals power conversion efficiency (PCE) of 8.27%, whereas the DSSC module exhibited a PCE of 5.18%. By using the fabricated DSSC module, an electric motor (15 mW) was operated both in indoor and outdoor light conditions. The procedures followed in this work pave a way for the easy fabrication of composite CE towards transparent DSSC modules and further the integration of the DSSC module with the standard Si solar cell is of great potential for various real-time application.

The low density of porous carbon nanomaterials for supercapacitor electrodes has limited their widespread application, despite their ultra-high gravimetric capacitance. In this work, we successfully prepared highly densified composite electrodes of graphene and single-walled carbon nanohorns (SWCNHs) using a simple spray-drying method that is suitable for mass production. To prepare the high-density composite electrodes, water-based mixtures of oxidized SWCNHs (NHOs) and graphene oxides (GOs) were spray-dried in heated air; after spray-drying, GOs dispersed in water were agglomerated in spherical clusters containing NHO nanoparticles. The reduced spray-dried GO/NHO (rS-GO/NHO) composite electrodes exhibited an extremely high bulk density of 1.23 g·cm−3, which is almost double that of commercial activated carbon (AC) and reduced NHO (r-NHO) electrodes, and three times higher than that of rS-GO electrodes. Of the materials tested, the rS-GO/NHO composite electrode had the highest volumetric capacitance (80 F·cm−3 at 1 mA·cm−2) and a low sheet resistance (0.005 Ω· sq.−1), which are far superior to those of commercial AC (57 F·cm−3 at 1 mA·cm−2 and 0.293 Ω·sq.−1, respectively), without the need for a conductive material, such as carbon black. We expect that these high-density graphene/SWCNH composite electrodes with high volumetric capacitances can be substituted for commercial AC materials in energy storage devices, such as supercapacitors.

A glassy carbon electrode (GCE) modified with single-walled carbon nanohorns (SWCNH) and zein (ZE), a prolamin type-protein find in maize, for the differential pulse adsorptive cathodic stripping voltammetric determination of fenitrothion (FT) is proposed. The proposed film was characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Regarding the electrochemical characterization, comparing the results obtained by cyclic voltammetry and electrochemical impedance spectroscopy, the modified electrode (SWCNH-ZE/GCE) showed an electroactive surface area 3 times higher and faster electron transfer kinetic than bare GCE. By using differential pulse adsorptive cathodic stripping voltammetry and SWCNH-ZE/GCE the analytical curve exhibited a linear response ranging of 9.9 × 10−7 to 1.2 × 10−5 mol L−1, with a limit of detection of 1.2 × 10−8 mol L−1. The proposed sensor was successfully applied for the determination of FT pesticide in natural water and orange juice samples. Moreover, the electrochemical sensor showed good repeatability and reproducibility arising from the excellent film stability, suggesting that the proposed architecture has broad potential for applications in sensing and biosensing.

γ-valerolactone (GVL) is a fine chemical which is widely used as a green solvent, a fuel additive and a green fuel. It can be produced from lignocellulosic biomass and its derivatives, such as methyl levulinate (ML) via catalytic hydrogenation reaction. In this work, novel hybrid materials of Ni nanoparticles and single-walled carbon nanohorns (Ni/CNHs) synthesized from gas-injected arc-in-water (GI-AIW) method was used as catalysts for producing GVL from ML. Effect of surface modification, oxidation and reduction of Ni/CNHs on their catalytic activity was investigated. For comparison of catalytic activities, Ni on other carbon supports prepared by the conventional wet impregnation and unsupported Ni catalysts were examined. X-ray diffractometry (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), N2 sorption, thermogravimetric analysis (TGA), Hydrogen-temperature-programmed reduction (H2-TPR), and Fourier Transform Infrared (FT-IR) spectroscopy were employed for elucidating different characteristics of all examined catalysts. It was found that reduced oxidized Ni/CNHs exhibited the highest catalytic performance with 96% conversion of ML, 90% yield, and 93% selectivity of GVL.

Among various carbon materials, nitrogen doped single walled carbon nanohorns (N-SWCNHs) have a unique structure of clustered conical cages (2–5 nm in diameter and 40–50 nm in length) arranged in dahlia, bud and seed-like configurations. Each conical cage has five pentagons at their tips which act as potential reactive site with their own distinct chemistry. We exploited these reactive sites of N-SWCNHs by preferentially growing germanium nanocrystals (Ge NCs) onto their conical tips using oleylamine as a mild reducing agent. Therefore, Ge decorated N-SWCNHs (Ge@N-SWCNHs) composite was used, for the first time, as active anode material for lithium ion batteries providing high and stable capacity of 1285 mAh/g at 0.1C after 100 cycles. Our results show that preferential growth of Ge Nanocrystals (NCs) on the tips of N-SWCNHs not only allows high utilization of active material but prevents the aggregation of Ge NCs after multiple cycling. Finally, we highlight the potential role of N-SWCNHs as cheap and industrially scalable conductive host for next generation lithium ion batteries.

Application of carbon nanomaterials to near-infrared light-mediated phototherapy has attracted great interest. However, their practical use in biological systems is severely limited by their poor water dispersibility, inevitable adsorption of plasma proteins, and their single therapeutic function. Herein, we prepared a phycocyanin (PC)-functionalized single-walled carbon nanohorns (PC@SWNHs) hybrid, where PC is used to preform a protein corona around the SWNHs through non-covalent interface interactions. In the PC@SWNHs, the preformed PC corona effectively improves the water dispersibility of the SWNHs and protects them from plasma protein adsorption. In addition, the excellent photodynamic activity of PC overcomes the inability of SWNHs to generate reactive oxygen species. The SWNHs not only give the hybrid a photothermal therapy (PTT) function, but they also enhance the photostability of PC. These characteristics of the PC@SWNHs are confirmed by in vitro and in vivo experiments, where synergistic photodynamic therapy (PDT)/PTT growth inhibition of tumors is achieved. The PC@SWNHs also act as a photoacoustic/thermal imaging agent to visualize the in vivo treatment process. Hence, this work not only paves the way to use the complementarity between SWNHs and proteins for multifunctional cancer theranostics, but it also allows for a better understanding of bio–nano interface interactions between them.

We firstly reveal the unique tendency in the capacitance of an electric double layer capacitor (EDLC) made of single-walled carbon nanohorns (SWCNHs), where there is an optimized value of specific surface area (SSA) to achieve the high capacitance value at a high charge-discharge rate. As a result, in the experimental observation, SWCNHs treated by oxidation in air at 550 °C can exhibit 963.4 m2/g of SSA and 286.6 F/g of EDLC capacitance, whereas the ones treated at 500 °C can exhibit 797.5 m2/g and 316.4 F/g at a high scan rate of 100 mV/s, although the SSA-capacitance relation seems ordinal at 5 mV/s. This result is against a common sense that the higher the SSA, the higher the EDLC capacitance. This unique relationship between the SSA of SWCNHs and the capacitance can be explained by consideration of the hierarchical pore structures of SWCNHs, including the internal mesopore zone and inner-core micropore zone, and the diffusion limitation of ionic species in these different structures. These pores are interlinked via the nanowindows opened by the oxidation treatment, and the nanowindow-link can be enhanced by temperature elevation from 500 to 550 °C, while the superficial mesopore can be partially destroyed at 550 °C.

Single-walled carbon nanohorns (SWNHs) have been shown to be effective photothermal enhancers and drug delivery agents for potential cancer therapy, particularly for the eradication of bladder cancer lesions. In this study, the potential for SWNHs to serve as nanotheranostic vehicles is demonstrated through simultaneous delivery of the chemotherapeutic cisplatin from SWNH cone interiors and imaging of the nanoparticle transport to tumor cells using conjugated quantum dots (QDs). Following the formation of cisplatin-modified SWNH-QD (SWNH-QD + cis) hybrids, their characterization by scanning and transmission electron microscopy (STEM, TEM), energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS) were performed to characterize the composite nanoparticles. Drug release profiles and 50% inhibitory concentration (IC50) determination showed that QDs do not hinder the therapeutic ability of SWNHs. In addition, the hybrids were trackable over the course of a 3 day period, which indicates that internalized SWNHs can continue to deliver therapy after removal of the nano-agents from the cell culture. This unique SWNH hybrid can successfully be used as an imaging agent to study nanoparticle transport and consequently the delivery of a therapeutic to the targeted cancer cells.

Fibrous aggregates of single-walled carbon nanohorns (carbon nanobrushes: CNBs) were prepared by CO2 laser ablation of an iron-containing carbon target with rotations under nitrogen atmosphere and ambient pressure. The rotation speed of the target and concentration of iron contained in it were controlled so as to increase the yield of CNBs. As a result, many CNBs were obtained at a rotation speed of 1 rpm and iron concentration above 1 at. %, although the samples still contained spherical single-walled carbon nanohorn aggregates (CNHs). The sheet resistivity of the samples containing both CNBs and CNHs decreased with the CNB content, which indicates that the CNBs formed a good conducting path. By forming supercapacitor electrodes, the capacitances of mixture of CNBs and CNHs, CNHs, and activated carbon were similar, i.e., 20, 21, and 23 F/g, respectively, at 0.1 A/g. However, the capacitance of the mixture of CNBs and CNHs at a discharge current of 5 A/g was about 1.4 and 6 times higher than that of the CNHs and activated carbon. These newly discovered CNBs should definitely increase the advantages of nanocarbon in various fields, especially in electronic devices.

The generation of hydrogen from water represents an important task towards a carbon neutral economy. Within this context, the preparation of hybrid electrodes merging the versatility of solid-state porous substrates and the catalytic ability and tunability of molecular complexes represents a great challenge. In the present work, we report on the preparation of hybrid cathodes for the hydrogen evolution reaction (HER) through an unprecedented combination of single-walled carbon nanohorns (SWCNHs) and two novel cobalt(II) polypyridine complexes based on the tris(2-pyridylmethyl)amine (TPMA) ligand scaffold. Suitable pyrene groups are introduced in the ligand framework in different positions to provide a way for direct anchoring onto the carbonaceous substrate by exploiting non-covalent π–π interactions. The present systems behave as competent cathodes for the HER in neutral aqueous solution with overpotentials of η ∼ 0.5 V and stable current densities (within 1 h electrolysis) up to −0.50 mA cm−2, whose exact values depend on the catalyst used and are mainly related to the respective loading on the electrode surface. In both cases, hydrogen evolution is detected under continuous electrolysis for up to ca. 12 h leading to maximum turnover numbers (TONs) of 4700 and 9180 molH2 molCo−1 for the two different complexes. The progressive deactivation under electrolytic conditions is mainly ascribed to leaching of the metal centre from the polydentate ligand, likely occurring from the competent catalytic intermediates involved in the HER.

Organic&ndash, inorganic ternary nanohybrids consisting of oxidized-single walled carbon nanohorns-SnO2-polyvinylpyrrolidone (ox-SWCNH/SnO2/PVP) with stoichiometry 1/1/1 and 2/1/1 and ox-SWCNH/ZnO/PVP = 5/2/1 and 5/3/2 (all mass ratios) were synthesized and characterized as sensing films of chemiresistive test structures for ethanol vapor detection in dry air, in the range from 0 up to 50 mg/L. All the sensing films had an ox-SWCNH concentration in the range of 33.3&ndash, 62.5 wt%. A comparison between the transfer functions and the response and recovery times of these sensing devices has shown that the structures with ox-SWCNH/SnO2/PVP = 1/1/1 have the highest relative sensitivities of 0.0022 (mg/L)&minus, 1, while the devices with ox-SWCNH/SnO2/PVP = 2/1/1 have the lowest response time (15 s) and recovery time (50 s) for a room temperature operation, proving the key role of carbonic material in shaping the static and dynamic performance of the sensor. These response and recovery times are lower than those of &ldquo, heated&rdquo, commercial sensors. The sensing mechanism is explained in terms of the overall response of a p-type semiconductor, where ox-SWCNH percolated between electrodes of the sensor, shunting the heterojunctions made between n-type SnO2 or ZnO and p-type ox-SWCNH. The hard&ndash, soft acid&ndash, base (HSAB) principle supports this mechanism. The low power consumption of these devices, below 2 mW, and the sensing performances at room temperature may open new avenues towards ethanol sensors for passive samplers of environment monitoring, alcohol test portable instruments and wireless network sensors for Internet of Things applications.

We investigated the electrochemical performance of single-walled carbon nanohorns (SWCNHs) for use as supercapacitor electrodes. For the first time, we used acid-treatment for oxidation of SWCNHs and hole creation in their structure. A detailed study was performed on the correlation between the oxidation of SWCNHs via acid treatment and variable acid treatment times, the structural properties of the oxidized carbon nanostructures, and the specific capacitance of the SWCNH electrodes. We showed that simple functionalization of carbon nanostructures under controlled conditions leads to an almost 3-fold increase in their specific capacitance (from 65 to 180 F g−1 in 0.1 M H2SO4). This phenomenon indicates higher accessibility of the surface area of the electrodes by electrolyte ions as a result of gradual opening of the SWCNH internal channels.

The low toxicity, high surface area, and ease of functionalisation of carbon nanohorns (CNH) makes them attractive systems for cellular imaging, diagnostics and therapeutics. However, challenges remain for the biomedical translation of these and other nanomaterials. A significant task is tuning the surface chemistry to achieve optimal cellular interactions. Herein, we combine real-time fluorescent imaging of nanoparticle cellular uptake and real-time differential interference contrast (DIC) imaging of extracellular media to monitor a) nanoparticle/nanoparticle and b) nanoparticle/cell interactions for CNHs covalently modified with an OFF/ON near-IR dye, the fluorescence of which is switched OFF in extracellular environments and triggered upon cellular internalisation. CHN samples modified with different loadings of the hydrophobic dye are taken as a simple model of drug-loaded nanoparticle systems. The punctate fluorescence suggests the CNHs are delivered to lysosomes and other vesicles of the endocytic pathway. DIC imaging highlights the competition that exists for many particle types, between extracellular aggregation and cellular internalization, the efficiency of which would be dependent upon the amount of fluorophore loading. The results of this study illustrate how complementary real-time imaging methods together with physicochemical characterisation can be used to address the challenges involved in optimising nanoparticle/cell interactions for biomedical applications. Irish Research Council Science Foundation Ireland University College Dublin

A novel amplified electrochemiluminescence (ECL) immunoassay based on single-walled carbon nanohorns (SWCNHs) labels and enzymatic biocatalytic precipitation (BCP) was proposed for the detection of neuron-specific enolase (NSE) for the first time. In this system, the dimercaptosuccinic acid stabilized CdTe (DMSA-CdTe) quantum dots (QDs) as ECL emitter showed excellent ECL behavior and then employed as the NSE antibody (Ab1) immobilization film for the subsequent sandwich-type Ab1-Ag affinity interactions. Improved sensitivity was achieved through using the SWCNHs effectively to expand the amount of secondary antibody (Ab2) and horseradish peroxidase (HRP) loading. In addition to the much enhanced steric hindrance, compared with the single HRP-Ab2, the presence of plentiful HRP would further stimulate the BCP onto the electrode surface for signal amplification, concomitant to the BCP products absorption that lowered ECL intensity. As a result of the multisignal amplification in this ECL immunosensor, it possessed excellent analytical performance. The target NSE could be detected from 1 × 10−9 g L−1 to 1 × 10−3 g L−1 with a detection limit of 4.4 × 10−10 g L−1.

Tumor combination therapy using nano formulations with multimodal synergistic therapeutic effects shows great potential for complete ablation of tumors. However, targeting tumor metastases with nano structures is a major obstacle for therapy. Therefore, developing a combination therapy system able to target both primary tumors and their metastases at distant sites with synergistic therapy is desirable for the complete eradication of tumors. To this end, a dual chemodrug-loaded theranostic system based on single walled carbon nanohorns (SWNHs) is developed for targeting both primary breast tumors and their lung metastases. Methods: SWNHs were first modified simultaneously with poly (maleic anhydride-alt-1-octadecene) (C18PMH) and methoxypolyethyleneglycol-b-poly-D, L-lactide (mPEG-PLA) via hydrophobic-hydrophobic interactions and π-π stacking. Then cisplatin and doxorubicin (DOX) (2.9:1 molar ratio) were sequentially loaded onto the modified nanohorns in a noninterfering way. After careful examinations of the release profiles of the loaded drugs and the photothermal performance of the dual chemodrug-loaded SWNHs, termed SWNHs/C18PMH/mPEG-PLA-DOX-Pt, the dual drug chemotherapeutic and chemo-photothermal synergetic therapeutic effects on tumor cells were evaluated. Subsequently, the in vivo behavior and tumor accumulation of the drug-loaded SWNHs were studied by photoacoustic imaging (PAI). For chemo-photothermal therapy of tumors, 4T1 tumor bearing mice were intravenously injected with SWNHs/C18PMH/mPEG-PLA-DOX-Pt at a dose of 10 mg/kg b.w. (in SWNHs) and tumors were illuminated by an 808 nm laser (1W/cm2 for 5 min) 24 h post-injection. Results: DOX and cisplatin were loaded onto the modified SWNHs with high efficiency (44 wt% and 66 wt%, respectively) and released in a pH-sensitive, tandem and sustainable manner. The SWNHs/C18PMH/mPEG-PLA-DOX-Pt had a hydrodynamic diameter of 182 ± 3.2 nm, were highly stable in physiological environment, and had both dual drug chemotherapeutic (CI = 0.439) and chemo-photothermal synergistic antitumor effects (CI = 0.396) in vitro. Moreover, the dual drug-loaded SWNHs had a long blood half-life (10.9 h) and could address both the primary breast tumors and their lung metastases after intravenous administration. Consequently, chemo-photothermal combination therapy ablated the primary tumors and simultaneously eradicated the metastatic lung nodules. Conclusion: Our study demonstrates that SWNHs/C18PMH/mPEG-PLA-DOX-Pt is highly potent for chemo-photothermal combination therapy of primary tumors and cocktail chemotherapy of their metastases at a distant site.

Poly(amic-acid) modified single-walled carbon nanohorns (PAA/SWCNH-COOH) contained dual-functional groups (amide and carboxyl) were synthesized by in-situ polymerization and used for the elimination of uranium (VI). It was found that the adsorption capacity of SWCNH-COOH increased significantly after grafting PAA chains, and the theoretical monolayer adsorption capacity of PAA/SWCNH-COOH could reach 216.0 mg/g. The adsorption capacity of this material could remain up to 90% of the initial value after 5 times of reuse. Moreover, PAA/SWCNH-COOH has an excellent adsorption selectivity, which could be attributed to the synergistic adsorption effects between amide and carboxyl groups. To further study the interaction mechanism between uranium ions and the adsorbents, the quantum chemical calculations were performed using DFT method. The simulation results show that both amide and carboxyl groups have a strong interaction with uranium ions, which ensures the high adsorption capacity of this material. This research proved that the PAA/SWCNH-COOH is a promising adsorption material for removing uranium from wastewater and it also sheds a light on the interaction mechanism between bifunctional adsorbents and uranium ions.

Ultrasonic-assisted liquid-phase exfoliation is one of high-efficiency strategies for preparing two-dimensional (2D) materials. Herein, we report a facile and green synthesis of the phosphorene (BP) obtained from bulk black phosphorus crystal in the ionic liquid (IL) 1-ethyl-3-methylimidazoliumtetrafluoroborate ([EMIm]BF4) through ultrasonic-assisted liquid-phase exfoliation under the continuous nitrogen atmosphere. To gain more insight, the morphology and composition of the as-prepared BP were characterized. The prepared BP showed satisfactory stability in ambient condition containing oxygen and water. In the following, single walled carbon nanohorn (SWCNH) was selected to enhance electrocatalytic capacity and endow oxidase-like (nanozyme) characteristics, which was further applied for electrochemical sensing of 5-hydroxytryptamine (5-HT). Derivative techniques were employed for treating voltammograms to obtain sharper and narrower voltammetric peak, transform asymmetric peak into much more symmetrical peak, reduce background interference, eliminate personal error and directly read the accurate value. Machine learning (ML) model based on artificial neural network (ANN) algorithm as an artificial intelligence approach is adopted to establish smart sensing system via the relationship between concentrations and currents in comparison with traditional linear regression model. The BP-IL-SWCNH nanozyme sensor displayed excellent electrocatalytic ability for second-order derivative voltammetric smart analysis of 5-HT range from 0.3 to 115 µM under optimal conditions.

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 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

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.

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.

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...

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.

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.

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.

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.

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.

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.