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Hollow Nanospheres (hollow + nanosphere)

Distribution by Scientific Domains
Polymers and Materials Science71%

Selected Abstracts

Designed Synthesis of Coaxial SnO2@carbon Hollow Nanospheres for Highly Reversible Lithium Storage

ADVANCED MATERIALS, Issue 24 2009
Xiong Wen Lou
A proof-of-concept structural design is demonstrated for high-capacity lithium-ion batteries anode materials by multistep synthesis of coaxial SnO2@carbon hollow nanospheres. This material integrates two beneficial features: hollow structure and carbon nanopainting. When evaluated for reversible lithium storage, these functional materials manifest excellent cycling performance and rate capabilities. [source]

Template-Free Synthesis of SnO2 Hollow Nanostructures with High Lithium Storage Capacity,

ADVANCED MATERIALS, Issue 17 2006
W. Lou
A facile one-step template-free method based on a novel inside-out Ostwald ripening mechanism is developed for inexpensive mass preparation of hollow and hollow core/shell-type SnO2 nanostructures using potassium stannate as the precursor. As-prepared SnO2 hollow nanospheres (see figure) exhibit ultrahigh lithium storage capacity and improved cycle performance as high-energy anode materials in lithium-ion secondary batteries. [source]

Fabrication of poly(aniline- co -pyrrole) hollow nanospheres with Triton X-100 micelles as templates

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2008
Chuanqiang Zhou
Abstract A one-step route has been reported for the fabrication of poly(aniline- co -pyrrole) (PACP) copolymer hollow nanospheres via the oxidation polymerization of a mixture of aniline and pyrrole in the presence of Triton X-100. It was found that the variations in polymerization conditions, such as the concentrations of Triton X-100 and comonomers, and [pyrrole]/[aniline] molar ratios, could change the size and uniformity of copolymer hollow nanospheres. The result of DLS has attested the presence of the spherical Triton X-100 micelles swelled by the comonomers in reaction system, and such micelles might play template for the formation of hollow nanospheres, followed by developing a possible formation mechanism. The chemical structures and crystallinity of products were characterized by FTIR, UV,visible, 1H NMR spectra, and XRD patterns, respectively, to prove the copolymer chemical structures of hollow nanospheres. The thermal-stability and solubility of PACP were improved compared with homopolymers (polyaniline and pyrrole). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3563,3572, 2008 [source]

A General Method for the Rapid Synthesis of Hollow Metallic or Bimetallic Nanoelectrocatalysts with Urchinlike Morphology

CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2008
Shaojun Guo
Abstract We have reported a facile and general method for the rapid synthesis of hollow nanostructures with urchinlike morphology. In-situ produced Ag nanoparticles can be used as sacrificial templates to rapidly synthesize diverse hollow urchinlike metallic or bimetallic (such as Au/Pt) nanostructures. It has been found that heating the solution at 100,°C during the galvanic replacement is very necessary for obtaining urchinlike nanostructures. Through changing the molar ratios of Ag to Pt, the wall thickness of hollow nanospheres can be easily controlled; through changing the diameter of Ag nanoparticles, the size of cavity of hollow nanospheres can be facilely controlled; through changing the morphologies of Ag nanostructures from nanoparticle to nanowire, hollow Pt nanotubes can be easily designed. This one-pot approach can be extended to synthesize other hollow nanospheres such as Pd, Pd/Pt, Au/Pd, and Au/Pt. The features of this technique are that it is facile, quick, economical, and versatile. Most importantly, the hollow bimetallic nanospheres (Au/Pt and Pd/Pt) obtained here exhibit an area of greater electrochemical activity than other Pt hollow or solid nanospheres. In addition, the ,6,nm hollow urchinlike Pt nanospheres can achieve a potential of up to 0.57,V for oxygen reduction, which is about 200,mV more positive than that obtained by using a ,6,nm Pt nanoparticle modified glassy carbon (GC) electrode. Rotating ring-disk electrode (RRDE) voltammetry demonstrates that ,6,nm hollow Pt nanospheres can catalyze an almost four-electron reduction of O2 to H2O in air-saturated H2SO4 (0.5,M). Finally, compared to the ,6,nm Pt nanoparticle catalyst, the ,6,nm hollow urchinlike Pt nanosphere catalyst exhibits a superior electrocatalytic activity toward the methanol oxidation reaction at the same Pt loadings. [source]