scholarly journals Synthesis and Photocatalytic Properties of CuO-CuS Core-Shell Nanowires

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1106 ◽  
Author(s):  
Yuan-Tse Kao ◽  
Shu-Meng Yang ◽  
Kuo-Chang Lu
Keyword(s):  
Surface Area ◽  
Dye Degradation ◽  
Horizontal Tube ◽  
Processing Parameters ◽  
Photocatalytic Properties ◽  
Polluted Water ◽  
Core Shell ◽  
Cuo Nanowires ◽  
Transmission Electron ◽  
Shell Nanowires

In this study, an efficient method to synthesize CuO-CuS core-shell nanowires by two-step annealing process was reported. CuO nanowires were prepared on copper foil via thermal oxidation in a three-zone horizontal tube furnace. To obtain larger surface area for photocatalytic applications, we varied four processing parameters, finding that growth at 550 °C for 3 h with 16 °C/min of the ramping rate under air condition led to CuO nanowires of appropriate aspect ratio and number density. The second step, sulfurization process, was conducted to synthesize CuO-CuS core-shell nanowires by annealing with sulfur powder at 250 °C for 30 min under lower pressure. High-resolution transmission electron microscopy studies show that a 10 nm thick CuS shell formed and the growth mechanism of the nanowire heterostructure has been proposed. With BET, the surface area was measured to be 135.24 m2·g−1. The photocatalytic properties were evaluated by the degradation of methylene blue (MB) under visible light irradiation. As we compared CuO-CuS core-shell nanowires with CuO nanowires, the 4-hour degradation rate was enhanced from 67% to 89%. This could be attributed to more effective separation of photoinduced electron and hole pairs in the CuO-CuS heterostructure. The results demonstrated CuO-CuS core-shell nanowires as a promising photocatalyst for dye degradation in polluted water.

Growth and Optical Properties of GaP, GaP@GaN and GaN@GaP Core-shell Nanowires

2003 ◽  
Vol 776 ◽  
Author(s):  
Hung-Min Lin ◽  
Jian Yang ◽  
Yong-Lin Chen ◽  
Yau-Chung Liu ◽  
Kai-Min Yin ◽  
...  
Keyword(s):  
Phonon Mode ◽  
Piezoelectric Effect ◽  
Lattice Mismatch ◽  
Core Shell ◽  
Photoluminescence Intensity ◽  
X Ray ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Surface Phonon Mode ◽  
Shell Nanowires

AbstractHigh-quality GaP, GaP@GaN and GaN@GaP nanowires were grown by a convenient vapor deposition technique. The wire-like and two-layers structures of GaP@GaN and GaN@GaP core-shell nanowires were clearly resolved using X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) and their growth directions were identified. Photoluminescence intensity of GaP@GaN nanowires increased as temperature increased. The result was interpreted by the piezoelectric effect induced from lattice mismatch between two semiconductor layers. An unexpected peak at 386 cm-1 was found in the Raman spectra of GaN@GaP and assigned to a surface phonon mode due to the interface. Detailed synthetic conditions and possible growth mechanisms of those nanowires were proposed.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

Hydrogen generation enhanced by nano-forest structures

RSC Advances ◽  
2016 ◽  
Vol 6 (16) ◽  
pp. 12953-12958 ◽  
Author(s):  
Keumyoung Seo ◽  
Taekyung Lim ◽  
Edmund M. Mills ◽  
Sangtae Kim ◽  
Sanghyun Ju
Keyword(s):  
Surface Area ◽  
Hierarchical Structure ◽  
Hydrogen Generation ◽  
Three Dimensional ◽  
Core Shell ◽  
Porous Disk ◽  
One Dimensional ◽  
Reaction Surface ◽  
Shell Nanowires

A hierarchical structure of one-dimensional CeO2/SnO2 core–shell nanowires on a three-dimensional porous disk (namely the “nanowire forest”) could maximize the reaction surface area and avoid coarsening during hydrogen generation.

scholarly journals Bi Incorporation and Segregation in the MBE-Grown GaAs-(Ga,Al)As-Ga(As,Bi) Core-Shell Nanowires

2021 ◽  
Author(s):  
Janusz Sadowski ◽  
Anna Kaleta ◽  
Serhii Kryvyi ◽  
Dorota Janaszko ◽  
Bogusława Kurowska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Flux Ratio ◽  
Growth Conditions ◽  
Nanowire Growth ◽  
Core Shell ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Shell Nanowires

Abstract Incorporation of Bi into GaAs-(Ga,Al)As-Ga(As,Bi) core-shell nanowires grown by molecular beam epitaxy is studied with transmission electron microscopy. Nanowires are grown on GaAs(100) substrates with Au-droplet assisted mode. Bi-doped shells are grown at low temperature (300 °C) with a close to stoichiometric Ga/As flux ratio. At low Bi fluxes, the Ga(As,Bi) shells are smooth, with Bi completely incorporated into the shells. Higher Bi fluxes (Bi/As flux ratio ~ 4%) led to partial segregation of Bi as droplets on the nanowires sidewalls, preferentially located at the nanowire segments with wurtzite structure. We demonstrate that such Bi droplets on the sidewalls act as catalysts for the growth of branches perpendicular to the GaAs trunks. Due to the tunability between zinc-blende and wurtzite polytypes by changing the nanowire growth conditions, this effect enables fabrication of branched nanowire architectures with branches generated from selected (wurtzite) nanowire segments.

Ag–Ni core–shell nanowires with superior electrocatalytic activity for alkaline hydrogen evolution reaction

2017 ◽  
Vol 5 (32) ◽  
pp. 16646-16652 ◽  
Author(s):  
Cong Zhang ◽  
Sijia Liu ◽  
Zhongzhang Mao ◽  
Xin Liang ◽  
Biaohua Chen
Keyword(s):  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electrocatalytic Activity ◽  
Active Surface ◽  
Core Shell ◽  
Active Surface Area ◽  
Electrochemically Active ◽  
Electrochemically Active Surface ◽  
Shell Nanowires

Ag–Ni nanowires with high electrochemically active surface area and small impedances were synthesized to show enhanced alkaline HER activity.

scholarly journals Preparation of Porous MnO@C Core-Shell Nanowires as Anodes for Lithium-Ion Batteries

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Shouhui Chen ◽  
Yaqin Chen ◽  
Rihui Zhou ◽  
Jiafeng Wu ◽  
Yonggui Song ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Surface Area ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Bet Surface Area ◽  
Core Shell ◽  
Electrochemical Performances ◽  
Phase Purity ◽  
Shell Nanowires

Porous MnO@C core-shell nanowires were prepared via a simple and facile method. The morphologies, the phase purity, the mass contents, and the BET surface area of the composite were characterized by SEM, XRD, TGA, and N2adsorption test, respectively. When the composite served as an anode for lithium-ion batteries, it showed superior electrochemical performances. The MnO@C composite presented a reversible capacity of 448.1 mAh g−1after 100 cycles at the current rate of 200 mA g−1.

Unveiling hidden epitaxial interfaces in novel SnO2/Zn2SnO4 core–shell nanowires with a multi-domain shield via cross-sectional transmission electron microscopy

CrystEngComm ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1895-1902 ◽  
Author(s):  
Bojia Xu ◽  
Baobao Cao
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Core Shell ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Shell Nanowires

Hidden epitaxial interfaces were revealed via cross-sectional TEM study of novel quasi-hexagonal SnO2/Zn2SnO4 core–shell nanowires.

scholarly journals Synthesis and Characterization of ZnO/ZnS Core/Shell Nanowires

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Taher Ghrib ◽  
Muneera Abdullah Al-Messiere ◽  
Amal Lafi Al-Otaibi
Keyword(s):  
Electron Microscopy ◽  
Thin Layer ◽  
Photoelectron Spectroscopy ◽  
Zno Nanowires ◽  
Core Shell ◽  
Wurtzite Phase ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Shell Nanowires

ZnO nanowires of approximately 3 µm length and 200 nm diameter are prepared and implanted vertically on substrate glass which is coated with thin layer of ITO which is too covered with bulk ZnO thin layer via electrodeposition process by cyclic voltammetry-chronoamperometry and with a chemical process that is described later; we have synthesized a ZnS nanolayer. ZnO/ZnS core/shell nanowires are formed by ZnO nanowires core surrounded by a very thin layer of porous ZnS shell principally constituted with a crystal which is about 15–20 nm in diameter. In the method, ZnS nanoparticles were prepared by reaction of ZnO nanowires with Na2S in aqueous solution at low temperature and also we have discussed the growth mechanism of ZnO/ZnS nanowires. The morphology, structure, and composition of the obtained nanostructures were obtained by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). For the structure, SEM and XRD measurements indicated that the as-grown ZnO nanowires microscale was of hexagonal wurtzite phase with a high crystalline quality, and TEM shows that the ZnS is uniformly distributed on the surface of the ZnO nanowires.

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