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1.
AbstractThe use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CNx-MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CNx-MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL?1. With Lac/CNx-MWCNT at concentrations of 6.4 mmol L?1 activity was 9326 U mL?1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L?1 was 9 234 U mL?1. The Lac/CNx-MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CNx-MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10?8 mol L?1 by measuring the electric current responses. 相似文献
2.
D. Pontiroli M. Riccò T. Shiroka M. Belli G. Ruani D. Palles 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(2-3):391-400
Abstract The low‐doped Li x C60 compounds (x≤6) were investigated using laboratory X‐ray and synchrotron radiation diffraction, 13C NMR and Raman spectroscopy. Li4C60 shows an unusual 2D polymerisation in which the C60 units are connected both by [2+2] cycloaddition and by single carbon–carbon bonds, a unique feature among the known polymerised fullerene compounds. This picture is fully supported also by static NMR and Raman measurements. The charge transfer to C60 in the polymeric phase was evaluated from the shift of the Ag(2) mode. The depolymerisation process was investigated as well; despite the presence of two different bonds, the polymer‐to‐monomer transition induced by thermal treatments is a single‐step phenomenon. 相似文献
3.
《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(1-2):155-158
Abstract The method for the synthesis of fullerols C60(OH) x was developed, allowing to obtain products with low number of hydroxy groups attached to fullerene molecule. At the first stage, product C60(tert‐BuO) x was obtained by the radical reaction of C60 with tert‐butyl‐peroxide under heating or UV‐irradiation. At the second stage, fullerol C60(OH) x was synthesized after the elimination of tert‐butyl groups by acid treatment. Several samples C60(OH) x containing different numbers (x = 2–5) of hydroxy groups were obtained, the main product had x = 2. The structure of the fullerols was confirmed by UV‐ and Fourier‐transform infrared (FTIR)‐spectroscopy and MALDI‐TOF mass‐spectrometry. 相似文献
4.
V. D. Blank D. V. Batov B. A. Kulnitskiy E. V. Polyakov I. A. Perezhogin D. A. Podgorny Yu. N. Parkhomenko 《Journal of Superhard Materials》2007,29(4):206-212
The method for the production of multiwall Y-junction bamboo-like CN x nanotubes by the resistive heating of graphite is described. Different branched bamboo-like CN x nanotubes have been observed. The possible mechanism of the formation of branched nanotubes is proposed. 相似文献
5.
Sulfur‐Modified Graphitic Carbon Nitride Nanostructures as an Efficient Electrocatalyst for Water Oxidation
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Vinayak S. Kale Uk Sim Jiwoong Yang Kyoungsuk Jin Sue In Chae Woo Je Chang Arun Kumar Sinha Heonjin Ha Chan‐Cuk Hwang Junghyun An Hyo‐Ki Hong Zonghoon Lee Ki Tae Nam Taeghwan Hyeon 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(17)
There is an urgent need to develop metal‐free, low cost, durable, and highly efficient catalysts for industrially important oxygen evolution reactions. Inspired by natural geodes, unique melamine nanogeodes are successfully synthesized using hydrothermal process. Sulfur‐modified graphitic carbon nitride (S‐modified g‐CN x ) electrocatalysts are obtained by annealing these melamine nanogeodes in situ with sulfur. The sulfur modification in the g‐CN x structure leads to excellent oxygen evolution reaction activity by lowering the overpotential. Compared with the previously reported nonmetallic systems and well‐established metallic catalysts, the S‐modified g‐CN x nanostructures show superior performance, requiring a lower overpotential (290 mV) to achieve a current density of 10 mA cm?2 and a Tafel slope of 120 mV dec?1 with long‐term durability of 91.2% retention for 18 h. These inexpensive, environmentally friendly, and easy‐to‐synthesize catalysts with extraordinary performance will have a high impact in the field of oxygen evolution reaction electrocatalysis. 相似文献
6.
Wegelin Frederik Christian Ziethen Ralph Ohr Dipl.‐Phys. Marc Neuhäuser Dipl.‐Phys. Heinz Hilgers Dr. Gerd Schönhense Prof. Dr. 《真空研究与实践》2001,13(5):287-292
Carbon and carbon nitride films are widely used as protective overcoats. Especially in magnetic hard disk drive industry there is a need for wear resistant and corrosion preventing overcoats with a thickness of some few nanometers. X‐ray Photoemission Electron Microscopy is a versatile tool to analyze carbon overcoats among others. Information about local bonding environment can be achieved by recording X‐ray Absorption Near Edge Structures (XANES). CVD DLC, a‐C and CNx coating have been analyzed. The fractions of sp2‐hybridized carbon atoms have been determined for a‐C overcoats and its correlation to mechanical properties could be shown. A scratch test has been performed on a CNx overcoat on a magnetic disk and analyzed with X‐PEEM afterwards. 相似文献
7.
Sustainable Synthesis of Co@NC Core Shell Nanostructures from Metal Organic Frameworks via Mechanochemical Coordination Self‐Assembly: An Efficient Electrocatalyst for Oxygen Reduction Reaction
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Shaik Gouse Peera Jayaraman Balamurugan Nam Hoon Kim Joong Hee Lee 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(19)
Herein, a new type of cobalt encapsulated nitrogen‐doped carbon (Co@NC) nanostructure employing ZnxCo1?x(C3H4N2) metal–organic framework (MOF) as precursor is developed, by a simple, ecofriendly, solvent‐free approach that utilizes a mechanochemical coordination self‐assembly strategy. Possible evolution of ZnxCo1?x(C3H4N2) MOF structures and their conversion to Co@NC nanostructures is established from an X‐ray diffraction technique and transmission electron microscopy analysis, which reveal that MOF‐derived Co@NC core–shell nanostructures are well ordered and highly crystalline in nature. Co@NC–MOF core–shell nanostructures show excellent catalytic activity for the oxygen reduction reaction (ORR), with onset potential of 0.97 V and half‐wave potential of 0.88 V versus relative hydrogen electrode in alkaline electrolyte, and excellent durability with zero degradation after 5000 potential cycles; whereas under similar experimental conditions, the commonly utilized Pt/C electrocatalyst degrades. The Co@NC–MOF electrocatalyst also shows excellent tolerance to methanol, unlike the Pt/C electrocatalyst. X‐ray photoelectron spectroscopy (XPS) analysis shows the presence of ORR active pyridinic‐N and graphitic‐N species, along with CoNx? Cy and Co? Nx ORR active (M–N–C) sites. Enhanced electron transfer kinetics from nitrogen‐doped carbon shell to core Co nanoparticles, the existence of M–N–C active sites, and protective NC shells are responsible for high ORR activity and durability of the Co@NC–MOF electrocatalyst. 相似文献
8.
A. P. Rubshtein I. Sh. Trakhtenberg E. G. Volkova A. B. Vladimirov V. A. Yugov A. G. Gontar V. N. Tkach 《Journal of Superhard Materials》2007,29(3):142-146
The structure of a-C and CN x coatings 1–3 μ thick deposited on metal substrates by arc-pulse sputtering of graphite target in nitrogen background at P = (10?2 ?5) Pa was studied by transmission electron microscopy and scanning electron microscopy. Concentration and depth distribution of nitrogen in CN x depend on progressive saturation of graphite target. Nitrogen-free coatings (x = 0) consist of amorphous matrix with multiwalled nanotubes. Structure of carbon nitride coatings depends on nitrogen concentration. Over the range of CN/CC < 0.15 and CN/CC > 0.4 CN x coatings are amorphous. The structure of CN0.15<x<0.4 is a mixture of two types of amorphous domains, one of which is decorated by microcrystalline inclusions. The same structured inclusions were found on graphite target modified by electric arc. The obtained results allow understanding the dependence of the CN0≤x≤0.5 coatings properties on nitrogen concentration. 相似文献
9.
Sergio A Aguila David Shimomoto Franscisco Ipinza Zaira I Bedolla-Valdez José Romo-Herrera Oscar E Contreras Mario H Farías Gabriel Alonso-Nú?ez 《Science and Technology of Advanced Materials》2015,16(5)
The use of nanomaterials allows the design of ultrasensitive biosensors with advantages in the detection of organic molecules. Catechol and catechin are molecules that occur naturally in fruits, and their presence in products like dyes and wines affects quality standards. In this study, catechol and catechin were measured at the nanoscale by means of cyclic voltammetry. The oxidation of Coriolopsis gallica laccase immobilized on nitrogen-doped multiwalled carbon nanotubes (Lac/CNx-MWCNT) and on graphene oxide (Lac/GO) was used to measure the concentrations of catechol and catechin. Nitrogen-doped multiwalled carbon nanotubes (CNx-MWCNT) were synthesized by spray pyrolysis and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Covalently bonded hybrids with laccase (Lac/CNx-MWCNT and Lac/GO) were generated. Catalytic activity of free enzymes determined with syringaldazine yielded 14 584 UmL−1. With Lac/CNx-MWCNT at concentrations of 6.4 mmol L−1 activity was 9326 U mL−1, while enzyme activity measured with Lac/GO at concentration of 6.4 mmol L−1 was 9 234 U mL−1. The Lac/CNx-MWCNT hybrid showed higher stability than Lac/GO at different ethyl alcohol concentrations. The Lac/CNx-MWCNT hybrid can measure concentrations, not previously reported, as low as 1 × 10−8 mol L−1 by measuring the electric current responses. 相似文献
10.
Shin-ichi Aoqui Tamiko Ohshima Tomoaki Ikegami Kenji Ebihara 《Science and Technology of Advanced Materials》2013,14(3-4):533-537
Pulsed laser deposition (PLD) technique has been widely used in thin film preparation because of its wonderful and excellent properties and amorphous carbon nitride (CNx) thin films are recognized to have potential for applications like hard coating and electron field emission device. We have deposited CNx thin films by KrF excimer laser – (λ= 248 nm) ablation of pure graphite target in pure NO gas ambient condition. In this paper, we have prepared the CNx thin films at various ambient NO gas pressure of 1.3–26 Pa and laser fluence of 2– 5J cm?2 on Si (100) substrate. We consider that the hardness of CNx thin films improves due to the increase the nitrogen/carbon (N/C) ratio. The N/C ratio depended on the ambient NO gas pressure and laser fluence. We obtainedthe maximum N/C ratio of 1.0 at NO 3.3 Pa. The typical absorption of CN bonds such as sp2 C–N, sp3 C–N, G band and D band were detected from the infrared absorption measurement by FTIR in the deposited CNx thin films. 相似文献
11.
Yiran Wang 《Materials Letters》2009,63(2):206-208
We developed a simple method to prepare individual nitrogen-containing carbon (CNx) nanobells with high yield. A mass of nanobells were produced from polymerized CNx nanobells by in situ plasma etching inside a chemical vapor deposition chamber. Scanning electron microscopy and transmission electron microscopy characterization reveals that the polymerized nanobells have been totally separated into individual nanobells, where each nanobell keeps its structure as that before etched. The present method sheds a light in the large-scale production of size-controllable short nanotubes. 相似文献
12.
CN
x
/TiN
y
multilayers were prepared by ion-beam sputtering and analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive X-ray (EDX). EDX results show that the atom ratios of [N]/([C] + [N] + [Ti]) in the multilayers vary from 20 at.% to 41 at.%. XPS analysis presents that the N content of the CN
x
layer in CN
x
/TiN
y
is about 32.18 at.%. The nature of chemical bonding of the CN
x
layer in CN
x
/TiN
y
was also analyzed. The X-ray and electron diffraction analyses suggest that three kinds of C3N4 phases, such as -C3N4, graphite-C3N4 and cubic-C3N4, are embodied in the multilayers. In CN
x
/TiN
y
bilayers, a hetero-epitaxial relationships, of (1 1 2) cubic-C3N4//(1 1 13) Ti2N, and [42 3¯] cubic-C3N4//[1 1¯ 0] Ti2N, was observed between cubic-C3N4 and Ti2N. 相似文献
13.
M. Akiyama I. Alexandrou M. Chhowalla G. A. J. Amaratunga 《Journal of Materials Science》2001,36(22):5397-5401
We have investigated the effects of seven sputtering control factors on the hardness of carbon nitride (CN
x
) thin films by design of experiments and the analysis of variance (ANOVA) to synthesize hard CN
x
thin films. It was determined statistically that the substrate temperature, the sputtering pressure and the target to substrate distance are significant control factors for the hardness of the CN
x
thin films within the experimental range of this study. Especially, the distance is the most important control factor of the seven factors; the hardest films are obtained at the distance of 4.5 cm. On the other hand, the effects of the substrate treatment, the dc power, the nitrogen concentration and the sputtering time are not statistically significant. It is suggested that these statistical methods are effective to compare the importance of many sputtering control factors. The CN
x
thin films deposited under the optimized sputtering conditions exhibit a relatively high hardness value of 55 ± 11 GPa, Young's modulus of 228 ± 21 GPa and an elastic recovery (%R) of 98%. The compressive stress in the films is a low value of 0.3 GPa. 相似文献
14.
Yi Lai Zhiai Xu Xianli Hu Li Lei Lingling Li Liang Dong Haijun Yu Wen Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(49)
1D peptide nanostructures (i.e., peptide nanotubes, PNTs) exhibit tunable chemo‐physical properties and functions such as improved tissue adhesion, increased cellular uptake, and elongated blood circulation. In this study, the application of PNTs as a desirable 1D template for biomineralization of Cu2?xS nanoparticles (Cu2?xS NPs, x = 1–2) is reported. Monodisperse Cu2?xS NPs are uniformly coated on the peptide nanotubes owing to the specific high binding affinity of Cu ions to the imidazole groups exposed on the surface of nanotubes. The Cu2?xS NP–coated PNTs are further covalently grafted with an oxaliplatin prodrug (Pt–CuS–PNTs) to construct a versatile nanoplatform for combination cancer therapy. Upon 808 nm laser illumination, the nanoplatform induces significant hyperthermia effect and elicits reactive oxygen species generation through electron transfer and Fenton‐like reaction. It is demonstrated that the versatile nanoplatform dramatically inhibits tumor growth and lung metastasis of melanoma in a B16‐F10 melanoma tumor‐bearing mouse model by combined photo‐ and chemotherapy. This study highlights the ability of PNTs for biomineralization of metal ions and the promising potential of such nanoplatforms for cancer treatment. 相似文献
15.
《Journal of Experimental Nanoscience》2013,8(16):1256-1268
Mn-doped ZnO nanoparticles, Zn1?xMnxO, were synthesised by a polyethylene glycol (PEG) sol–gel method and the physicochemical properties of compounds were characterised by atomic absorption spectroscopy (AAS), energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The catalytic degradation of an organic dye, methylene blue (MB), in the presence of Zn1?xMnxO as the catalyst and hydrogen peroxide (H2O2) as the oxidant at room temperature in water has been studied. Effects of oxidant, catalyst amount, catalyst composition, pH value of the solution and an OH-radical scavenging agent on the degree of the decomposition of MB dye were also studied. 相似文献
16.
Binary, ternary, and quaternary carbonitride materials, such as CNx, BCN, SiCN, SiBCN, AlBCN, are of significant industrial interest because of their light weight and multi‐functional properties, combining extreme hardness, oxidation resistance, and chemical inertness. The most exciting material in this family is carbon nitride C3N4 with expected ‘superdiamond’ properties. This report describes new approaches to the preparation of CNx thin films, and nanoscale or bulk solids of C3N4 and BCN. 相似文献
17.
《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(1-2):235-241
Abstract We show that application of the non‐hydrostatic pressure to the cluster‐based molecular material, like fullerite C60, provides a new opportunity to create elastically and structurally anisotropic carbon materials, including 2D polymerized rhombohedral C60 and graphite‐type (sp 2) disordered atomic‐based phases. The elastic anisotropy, detected by the difference in the ultrasound velocities propagating along and across the loading axis, is directly confirmed by the results of x‐ray diffraction. 相似文献
18.
Ning Fu Ying Liu Rui Liu Xiaodong Wang Zhenglong Yang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(20)
Nearly inexhaustible sodium sources on earth make sodium ion batteries (SIBs) the best candidate for large‐scale energy storage. However, the main obstacles faced by SIBs are the low rate performance and poor cycle stability caused by the large size of Na+ ions. Herein, a universal strategy for synthesizing amorphous metals encapsulated into amorphous B, N co‐doped carbon (a‐M@a‐BCN; M = Co, Ni, Mn) nanotubes by metal cation‐assisted carbonization is explored. The methodology allows tailoring the structures (e.g., length, wall thickness, and metals doping) of a‐M@a‐BCN nannotubes at the molecular level. Furthermore, the amorphous metal sulfide encapsulated into a‐BCN (a‐MSx@a‐BCN; MSx: CoS, Ni3S2, MnS) nanotubes are obtained by one‐step sulfidation process. The a‐M@a‐BCN and a‐MSx@a‐BCN possess the larger interlayer spacing (0.40 nm) amorphous carbon nanotube rich in heteroatoms active sites, making them exhibit excellent Na+ ions diffusion kinetics and capacitive storage behavior. As SIBs anodes, they show high capacity, excellent rate performance, and long cycle stability. 相似文献
19.
Abstract Pb1‐x Sn x Te epitaxial layers were successfully grown on PbTe substrates by liquid phase epitaxy (LPE) technique. The compositions and surface morphology of the epitaxial Pb1‐x Sn x Te layers were controlled in the LPE growth, and p‐Pb1‐x Sn x Te/n‐PbTe heterodiodes with a good junction‐perfection factor were made. 相似文献
20.
The ZnO/FeOx core/shell nanorods were prepared with ZnO nanorods as templates, on which ferric oxide was deposited by thermal decomposition of Fe(acac)3 in solution. The thickness of the ferric oxide shell could be precisely controlled by the concentration of Fe(acac)3. The amorphous ferric oxide nanotubes were fabricated by wet-etching the ZnO core nanorods in HAc solution and polycrystalline ZnFe2O4 nanotubes were prepared by annealing the core/shell ZnO/FeOx nanocomposites in air. The obtained ZnFe2O4 nanotubes showed paramagnetism at room temperature. 相似文献