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Find video protocols related to scientific articles indexed in Pubmed.
Highly porous structure strategy to improve the SnO2 electrode performance for lithium-ion batteries.
Phys Chem Chem Phys
PUBLISHED: 01-23-2014
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SnO2 is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability due to its huge volume variation during the lithium uptake and release process. In this work, SnO2 nanofibers and nanotubes with highly porous (HPNFs, HPNTs) structure have been synthesized by a facile emulsion electrospinning and subsequent calcination process in air at 500 °C. Pores with a diameter range of 2-30 nm were distributed evenly on the surface of the nanofibers and nanotubes. The HPNFs and HPNTs manifested high capacities and excellent cycle performance as the anode electrode for LIBs, and they can deliver reversible capacities of 583 and 645 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles, respectively. When the current density is up to 5 A g(-1), the electrodes still exhibit a good retention, and the reversible capacities were about 370 and 432 mA h g(-1), which performs much better than the nanofibers and nanotubes without a porous structure. Our results demonstrated that this simple method could be extended for the synthesis of porous metal oxide nanotubes with high performances in the applications of lithium ion batteries and other fields.
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Bio-Inspired Hierarchical Polymer Fiber-Carbon Nanotube Adhesives.
Adv. Mater. Weinheim
PUBLISHED: 09-12-2013
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Hierarchical pillar arrays consisting of micrometer-sized polymer setae covered by carbon nanotubes are engineered to deliver the role of spatulae, mimicking the fibrillar adhesive surfaces of geckos. These biomimetic structures conform well and achieve better attachment to rough surfaces, providing a new platform for a variety of applications.
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Super Long-Life Supercapacitors Based on the Construction of Nanohoneycomb-Like Strongly Coupled CoMoO4 -3D Graphene Hybrid Electrodes.
Adv. Mater. Weinheim
PUBLISHED: 08-17-2013
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Nanohoneycomb-like strongly coupled CoMoO4 -3D graphene hybird electrodes are synthesized for supercapacitors which exhibit excellent specific capacitance and superior long-term cycle stability. The supercapacitor device can power a 5 mm-diameter LED efficiently for more than 3 min with a charging time of only 2 s, and show high energy densities and good cycle stability.
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Electrospinning directly synthesized metal nanoparticles decorated on both sidewalls of TiO2 nanotubes and their applications.
Nanoscale
PUBLISHED: 05-20-2013
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The hybrid structure of nanoparticle-decorated nanotubes has the advantage of both large specific surface areas of nanoparticles and anisotropic properties of nanotubes, which is desirable for many applications. In this study, Ag nanoparticles on highly porous TiO2 nanotubes (NTs) on both internal and external sidewalls (Ag@TiO2@Ag NTs) are directly synthesized by emulsion electrospinning and thermal evaporation for the first time. The Ag@TiO2@Ag NT heterostructures, which have large surface-to-volume ratios, improved electrical conductivity, and an excellent material synergetic effect, demonstrate excellent electrochemical properties and superior photocatalytic performance. The new method for the synthesis of Ag@TiO2@Ag NT heterostructures can be applied to fabricate various types of other novel metal nanoparticles (for example Au and Pt) on highly porous nanotubes on both internal and external sidewalls. The possible growth mechanism and reasons for excellent electrochemical properties and superior photocatalytic performance were discussed in detail.
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Carbon and graphene double protection strategy to improve the SnO(x) electrode performance anodes for lithium-ion batteries.
Nanoscale
PUBLISHED: 05-15-2013
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SnOx is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. In this paper, SnOx carbon nanofibers (SnOx@CNFs) are firstly obtained in the form of a nonwoven mat by electrospinning followed by calcination in a 0.02 Mpa environment at 500 °C. Then we use a simple mixing method for the synthesis of SnOx@CNF@graphene (SnOx@C@G) nanocomposite. By this technique, the SnOx@CNFs can be homogeneously deposited in graphene nanosheets (GNSs). The highly scattered SnOx@C@G composite exhibits enhanced electrochemical performance as anode material for LIBs. The double protection strategy to improve the electrode performance through producing SnOx@C@G composites is versatile. In addition, the double protection strategy can be extended to the fabrication of various types of composites between metal oxides and graphene nanomaterials, possessing promising applications in catalysis, sensing, supercapacitors and fuel cells.
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Encapsulating gold nanoparticles or nanorods in graphene oxide shells as a novel gene vector.
ACS Appl Mater Interfaces
PUBLISHED: 03-21-2013
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Surface modification of inorganic nanoparticles (NPs) is extremely necessary for biomedical applications. However, the processes of conjugating ligands to NPs surface are complicated with low yield. In this study, a hydrophilic shell with excellent biocompatibility was successfully constructed on individual gold NPs or gold nanorods (NRs) by encapsulating NPs or NRs in graphene oxide (GO) nanosheets through electrostatic self-assembly. This versatile and facile approach remarkably decreased the cytotoxicity of gold NPs or NRs capping with surfactant cetyltrimethylammonium bromide (CTAB) and provided abundant functional groups on NPs surface for further linkage of polyethylenimine (PEI). The PEI-functionalized GO-encapsulating gold NPs (GOPEI-AuNPs) were applied to delivery DNA into HeLa cells as a novel gene vector. It exhibited high transfection efficiency of 65% while retaining 90% viability of HeLa cells. The efficiency was comparable to commercialized PEI 25 kDa with the cytotoxicity much less than PEI. Moreover, the results on transfection efficiency was higher than PEI-functionalized GO, which can be attributed to the small size of NPs/DNA complex (150 nm at the optimal w/w ratio) and the spherical structure facilitating the cellular uptake. Our work paves the way for future studies focusing on GO-encapsulating, NP-based nanovectors.
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Electrospinning-thermal treatment synthesis: a general strategy to decorate highly porous nanotubes on both internal and external side-walls with metal oxide/noble metal nanoparticles.
Nanoscale
PUBLISHED: 02-28-2013
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The hybrid structure of nanoparticle-decorated highly porous nanotubes combines the advantages of large specific surface areas of nanoparticles and anisotropic properties of highly porous nanotubes, which is desirable for many applications, including batteries, photoelectrochemical water splitting, and catalysis. Here, we report a novel emulsion electrospinning-thermal treatment method to synthesize the nanoparticles deposited on both side walls of nanotubes with two unique characteristics: (1) large loading amount of nanoparticles per highly porous nanotubes (with the morphology of nanoparticles); (2) intimate contact between nanoparticles and highly porous nanotubes. Both features are advantageous for the above applications that involve both surface reactions and charge transportation processes. Moreover, the emulsion electrospinning-thermal treatment method is simple and straightforward, with which we have successfully decorated various highly porous metal oxide nanotubes with metal oxide or noble metal nanoparticles. The new method will have an impact on diverse technologies such as lithium ion batteries, catalysts, and photoelectrochemical devices.
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Temperature effect on electrospinning of nanobelts: the case of hafnium oxide.
Nanotechnology
PUBLISHED: 06-09-2011
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Electrospinning is a convenient and versatile method for fabricating different kinds of one-dimensional nanostructures such as nanofibres, nanotubes and nanobelts. Environmental parameters have a great influence on the electrospinning nanostructure. Here we report a new method to fabricate hafnium oxide (HfO(2)) nanobelts. HfO(2) nanobelts were prepared by electrospinning a sol-gel solution with the implementation of heating and subsequent calcination treatment. We investigate the temperature dependence of the products by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive x-ray (EDX) spectroscopy. The heating temperature of spinning ambient is found to be crucial to the formation of HfO(2) nanobelts. By tuning the temperature, the morphological transformation of HfO(2) from nanowires to nanobelts was achieved. It was found that the rapid evaporation of solvent played an important role in the formation process of HfO(2) nanobelts. It is shown that nanobelts can only be obtained with the temperature higher than 50?°C and they are in the high quality monoclinic phase. A possible growth mechanism of the nanobelts based on phase separation is proposed. The enhanced photoluminescence (PL) of HfO(2):Eu(3+) nanobelts is also illustrated.
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Direct preparation of carbon nanotubes and nanobelts from polymer.
Nanoscale
PUBLISHED: 03-30-2011
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Carbon nanotubes and carbon nanobelts were obtained via single-needle electrospinning on a basis of water-in-oil (W/O) emulsion technique, respectively. The morphology of electrospun products can be controlled by controlling the temperature of the collector during the electrospinning process. The mechanism of fabricating PAN nanotubes and nanobelts by emulsion electrospinning is discussed in detail. Transmission electron microscopy and scanning electron microscope results show that the carbon nanotubes (the inner diameter of 25-50 nm and the outer diameter of 50-100 nm) have a wall thickness of 10-50 nm, and the width and thickness of the nanobelts range from 100 to 300 nm, and 1 to 5 nm, respectively. A slight difference of bonding configuration of the carbon nanofibers, carbon nanotubes and carbon nanobelts is attributed partly to their different topological structures. The novel method is versatile and could be extended to the fabrication of various types of nanotubes and nanobelts.
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High-performance photoelectrochemical-type self-powered UV photodetector using epitaxial TiO?/SnO? branched heterojunction nanostructure.
Small
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TiO?/SnO? branched heterojunction nanostructure with TiO? branches on electrospun SnO2 nanofiber (B-SnO? NF) networks serves as a model architecture for efficient self-powered UV photodetector based on a photoelectrochemical cell (PECC). The nanostructure simultaneously offers a low degree of charge recombination and a direct pathway for electron transport. Without correcting 64.5% loss of incident photons through light absorption and scattering by the F-doped tin oxide (FTO) glass, the incident power conversion efficiency reaches 14.7% at 330 nm, more than twice as large as the nanocrystalline TiO? (TiO? NC, 6.4%)-film based PECC. By connecting a PECC to an ammeter, the intensity of UV light is quantified using the output short-circuit photocurrent density (J(sc)) without a power source. Under UV irradiation, the self-powered UV photodetector exhibits a high responsivity of 0.6 A/W, a high on/off ratio of 4550, a rise time of 0.03 s and a decay time of 0.01 s for J(sc) signal. The excellent performance of the B-SnO? NF-based PECC type self-powered photodetector will enable significant advancements for next-generation photodetection and photosensing applications.
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?-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors.
Nanoscale
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Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper ?-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g(-1)) at a current density of 2 A g(-1), high-power density (11.98 kW kg(-1)) at a discharge current density of 40 A g(-1) and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.
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A facile method to prepare SnO2 nanotubes for use in efficient SnO2-TiO2 core-shell dye-sensitized solar cells.
Nanoscale
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A high-efficiency photoelectrode for dye-sensitized solar cells (DSSCs) should combine the advantageous features of fast electron transport, slow interfacial electron recombination and large specific surface area. However, these three requirements usually cannot be achieved simultaneously in the present state-of-the-art research. Here we report a simple procedure to combine the three conflicting requirements by using porous SnO(2) nanotube-TiO(2) (SnO(2) NT-TiO(2)) core-shell structured photoanodes for DSSCs. The SnO(2) nanotubes are prepared by electrospinning of polyvinyl pyrrolidone (PVP)/tin dichloride dihydrate (SnCl(2)·2H(2)O) solution followed by direct sintering of the as-spun nanofibers. A possible evolution mechanism is proposed. The power conversion efficiency (PCE) value of the SnO(2) NT-TiO(2) core-shell structured DSSCs (?5.11%) is above five times higher than that of SnO(2) nanotube (SnO(2) NT) DSSCs (?0.99%). This PCE value is also higher than that of TiO(2) nanoparticles (P25) DSSCs (?4.82%), even though the amount of dye molecules adsorbed to the SnO(2) NT-TiO(2) photoanode is less than half of that in the P25 film. This simple procedure provides a new approach to achieve the three conflicting requirements simultaneously, which has been demonstrated as a promising strategy to obtain high-efficiency DSSCs.
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A simple method for the preparation of hollow ZnO nanospheres for use as a high performance photocatalyst.
Nanoscale
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We have used classical electrospinning and subsequent thermal treatment to successfully fabricate hollow ZnO nanospheres. The hollow ZnO nanospheres were then used to study the degradation of Rhodamine B (RhB) dye and were proven to have excellent photocatalytic activity. The mechanism of formation of hollow ZnO nanospheres and the reason for the high photocatalytic activity were also investigated.
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Graphene-based composite materials beneficial to wound healing.
Nanoscale
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We use electrospinning to prepare chitosan-PVA nanofibers containing graphene. The nanofibers can be directly used in wound healing: graphene, as an antibacterial material, can be beneficial for this. A possible antibacterial mechanism for graphene is presented.
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Growth of ultrahigh density single-walled carbon nanotube forests by improved catalyst design.
ACS Nano
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We have grown vertically aligned single-walled carbon nanotube forests with an area density of 1.5 × 10(13) cm(-2), the highest yet achieved, by reducing the average diameter of the nanotubes. We use a nanolaminate Fe-Al(2)O(3) catalyst design consisting of three layers of Al(2)O(3), Fe, and Al(2)O(3), in which the lower Al(2)O(3) layer is densified by an oxygen plasma treatment to increase its diffusion barrier properties, to allow a thinner catalyst layer to be used. This high nanotube density is desirable for using carbon nanotubes as interconnects in integrated circuits.
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A new ultrahigh-speed method for the preparation of nanofibers containing living cells: a bridge towards industrial bioengineering applications.
Nanoscale
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A novel method is reported of producing nanofibers/nanotubes (measuring from tens of nanometres to several hundreds of nanometres) containing living cells, mechanically and with ultrahigh speed and at low cost. High-pressure gas was used to extrude viscous precursors through a spray with micron-sized holes into air. The sprayed micro-sized droplets had high velocity and were continuously elongated into uniform nanofibers/nanotubes in a temperature field during their flight. We demonstrated that the throughput of this spinning method to fabricate nanofibers/nanotubes from an individual setup could be as high as 10 g s(-1). A possible mechanism for this extrusion method was proposed based on flow mechanics and the experimental results. Additionally, it was shown that the new method could be used to directly prepare nanofibers containing living cells. It was demonstrated that the living cells with high survival rate can be used in bioengineering.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.