Facile Synthesis of Cobalt Oxide Uniformly Coated on Multi-Wall Carbon Nanotubes for Supercapacitors

2011 ◽  
Vol 306-307 ◽  
pp. 1148-1152 ◽  
Author(s):  
Liang Yu Gong ◽  
Ling Hao Su
Keyword(s):  
Carbon Nanotubes ◽  
Cobalt Oxide ◽  
Solid Phase ◽  
Synthesis Method ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Phase Synthesis ◽  
Multi Wall Carbon Nanotubes ◽  
Electrochemical Tests ◽  
Transmission Electron

The composite electrodes of cobalt oxide and multi-wall carbon nanotubes (MWCNTs) are prepared by a simple low-temperature solid-phase synthesis method with the assistance of polyethylene glycol and their pseudocapacitive performances are investigated in alkaline solution by cyclic voltammetry and galvanostatic charge/discharge tests, respectively. Transmission electron microscope images show that cobalt oxide is uniformly coated on multi-wall carbon nanotubes and the homogeneous hybrid nanostructure are considered to be responsible for their preferable electrochemical performances. The electrochemical tests further reveal that the composite can deliver a maximum specific capacitance of 217 F/g with a biggest utilization of Co element when the content of MWCNTs increases to 50 wt.%.

Study on Multi-Doped Ceria-Based Solid Electrolytes

2012 ◽  
Vol 519 ◽  
pp. 28-31
Author(s):  
Yong Li Yao ◽  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
Electron Microscopy ◽  
Solid Electrolytes ◽  
Solid Phase ◽  
Synthesis Method ◽  
Fluorite Structure ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
Phase Synthesis ◽  
Transmission Electron ◽  
Trivalent Cations

Doped ceria-based (Gd0.2Ce0.8O1.9, GDC) solid electrolytes were prepared by Solid-phase synthesis method. The effect of doping bismuth oxide and samarium oxide on the phase and microstructure of GDC was investigated. The phase composition was analyzed by the X-ray diffraction (XRD).The single cubic fluorite structure was observed after doping these oxides. Appearance and microstructure of doped ceria-based solid electrolytes were analyzed by the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The results showed that the doped trivalent cations had entered into the ceria structure uniformly. The density, porosity rate and water absorption of GDC were measured by Archimedes principle. It indicated that the density of doped GDC solid electrolyte increased with the rising of sintering temperature.

Electrochemical Performance of Iron and Cobalt Tetrapyrazinoporphyrazines Supported on Multiwalled Carbon Nanotubes

2013 ◽  
Vol 634-638 ◽  
pp. 2155-2159 ◽  
Author(s):  
Sen Liu ◽  
Jin Hua Lu ◽  
He Jun Li ◽  
Ying Bo Fei
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Solid Phase ◽  
Synthesis Method ◽  
Rotating Disk ◽  
Rotating Disk Electrode ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
O2 Reduction ◽  
One Step

Iron tetrapyrazinoporphyrazine (FePTpz) and cobalt tetrapyrazinoporphyrazines (CoPTpz) supported on multiwalled carbon nanotubes (MWCNTs) are prepared by solid phase synthesis method. The products are characterized by scanning and transmission electron microscopy. The electrocatalytic activity of the obtained MWCNTs-supported FePTpz and CoPTpz assemblies (MPTpz/MWCNTs) is measured by cyclic voltammetry and rotating disk electrode techniques in an oxygen-saturated 0.1M KOH. The results show that MPTpz/MWCNTs are more efficient than reference MPTpz. FePTpz/MWCNTs are more efficient for O2 reduction than CoPTpz/MWCNTs, both of FePTpz/MWCNTs and CoPTpz/MWCNTs exhibit a one-step, four-electron pathway for ORR.

MORPHOLOGY EFFECT OF Ni–Ag/CARBON NANOMATERIALS ON THEIR ELECTROCATALYTIC ACTIVITY FOR GLUCOSE OXIDATION

2016 ◽  
Vol 23 (06) ◽  
pp. 1650059 ◽  
Author(s):  
RUIZHUO OUYANG ◽  
WEIWEI LI ◽  
YANG YANG ◽  
WANGYAO ZHANG ◽  
KAI FENG ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Morphology ◽  
Active Sites ◽  
Carbon Nanomaterials ◽  
Modified Electrodes ◽  
Single Wall Carbon Nanotubes ◽  
Composite Electrodes ◽  
Ag Nps ◽  
Multi Wall Carbon Nanotubes ◽  
Ag Deposition

We presented here three carbon-nanomaterials-based modified glassy carbon electrodes (GCE) with Ni–Ag nanohybrid nanoparticles (NPs) deposited upon, including single-wall carbon nanotubes (SWCNTs), multi-wall carbon nanotubes (MWCNTs) and the mesoporous carbons (MPCs), and compared their morphology effects on both Ni–Ag deposition quality and electrocatalytic performances toward Glu oxidation. After being deposited with Ni–Ag NPs, a homogenous surface with very small Ni–Ag NPs was obtained for Ni–Ag/SWCNTs/GCE, while heterogeneous, coarse surfaces with obvious embedment with large Ni–Ag particles were observed for both Ni–Ag/MWCNTs/GCE and Ni–Ag/MPC/GCE. All three modified electrodes were well characterized in terms of surface morphology, electron transfer rate, hydrophilicity, interference resistance, stability, electrocatalytic behaviors as well as practicability in real samples, based on which Ni–Ag/SWCNTs/GCE was always proved to be more advantageous over other two composite electrodes. Such advantage of Ni–Ag/SWCNTs/GCE was attributed to its desirable surface morphology good for Ni–Ag deposition and exposure of as many active sites as possible to Glu oxidation, leading to the extraordinary electrocatalytic performance.

scholarly journals Enhanced Electrochemical Performances of Cobalt-Doped Li2MoO3 Cathode Materials

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 843 ◽  
Author(s):  
Zhiyong Yu ◽  
Jishen Hao ◽  
Wenji Li ◽  
Hanxing Liu
Keyword(s):  
Cathode Materials ◽  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Phase Method ◽  
Electrochemical Performances ◽  
X Ray ◽  
Electrochemical Tests ◽  
Co Doping ◽  
Solid Phase Method ◽  
Better Than

Co-doped Li2MoO3 was successfully synthesized via a solid phase method. The impacts of Co-doping on Li2MoO3 have been analyzed by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) measurements. The results show that an appropriate amount of Co ions can be introduced into the Li2MoO3 lattices, and they can reduce the particle sizes of the cathode materials. Electrochemical tests reveal that Co-doping can significantly improve the electrochemical performances of the Li2MoO3 materials. Li2Mo0.90Co0.10O3 presents a first-discharge capacity of 220 mAh·g−1, with a capacity retention of 63.6% after 50 cycles at 5 mA·g−1, which is much better than the pristine samples (181 mAh·g−1, 47.5%). The enhanced electrochemical performances could be due to the enhancement of the structural stability, and the reduction in impedance, due to the Co-doping.

Ultrasound promoted green oxidation of alkenes with hydrogen peroxide in the presence of iron porphyrins supported on multi-walled carbon nanotubes

2015 ◽  
Vol 19 (04) ◽  
pp. 622-630 ◽  
Author(s):  
Saeed Rayati ◽  
Zahra Sheybanifard
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Hydrogen Peroxide ◽  
Heterogeneous Catalyst ◽  
Multi Wall Carbon Nanotubes ◽  
Mechanical Stirring ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

In the present work, oxidation of alkenes with hydrogen peroxide in the presence of meso-tetrakis(4-hydroxyphenyl)porphyrinatoiron(III) chloride supported onto surface of functionalized multi-wall carbon nanotubes (FMWCNT), [ Fe ( THPP ) Cl@MWCNT ], is reported. The simple heterogeneous catalyst was characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and also thermal analysis. The amount of the catalyst loaded on the nanotubes was determined by atomic absorption spectroscopy. This heterogeneous catalyst proved to be an efficient and green catalyst and was successfully able to activate hydrogen peroxide without any additive toward the oxidation of alkenes in ethanol as a green solvent. Performance of the catalyst in oxidation of various alkenes was inspected under reflux, ultrasonic irradiation and mechanical stirring. Moreover, the catalyst can be reused several times under similar conditions.

Electrical Conductivity of Mixed Conductors (YO1.5)x-(CeO2)y-(ZrO2)1-x-y

2007 ◽  
Vol 336-338 ◽  
pp. 424-427
Author(s):  
Xiang Yong Zhou ◽  
Zeng Fan ◽  
Zi Long Tang ◽  
Zhong Tai Zhang
Keyword(s):  
Electrical Conductivity ◽  
Metal Ion ◽  
Solid Phase ◽  
Electronic Conductivity ◽  
Synthesis Method ◽  
Conductivity Measurement ◽  
Fluorite Structure ◽  
Charge Balance ◽  
Phase Synthesis ◽  
Oxygen Ion

The Y2O3-ZrO2 binary system ceramic is considered to be most developed in application to the ZrO2-based materials. A cubic fluorite structure is generally achieved, as the metal ion of the additive (Y) takes place of the Zr4+ and oxygen ion vacancies are produced in the lattice to maintain the charge balance. This leads to almost totally ionic conductivity. The introduction of changeable valued CeO2 can further improve the total electronic conductivity through the defect equilibrium reaction between tetravalent Ce4+ and trivalent Ce3+ at high temperature and reducing atmosphere. In this study, solid phase synthesis method was employed for the preparation of (YO1.5)x-(CeO2)0.08-(ZrO2)0.9-x and (YO1.5)0.05-(CeO2)y- (ZrO2)0.95-y ceramics, while four probe DC conductivity measurement method was also applied under the temperature between 300 to 800°C. The results prove that the concentration of Y3+ is the main contribution of the electrical conductivity at low temperature.

Multi-wall carbon nanotubes with nitrogen-containing carbon coating

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Elena Tomšík ◽  
Zuzana Morávková ◽  
Jaroslav Stejskal ◽  
Miroslava Trchová ◽  
Petr Šálek ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Carbon Coating ◽  
Covalent Bonding ◽  
Inert Atmosphere ◽  
New Materials ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes ◽  
Transmission Electron

AbstractPolyaniline coating was deposited on the surface of multi-wall carbon nanotubes of Russian and Taiwanese origin in situ during the polymerization of aniline. The deposited polyaniline film was subsequently carbonized under an inert atmosphere at various temperatures to produce coaxial coating of the carbon nanotubes with nitrogen-containing carbon. The new materials were investigated by infrared and Raman spectroscopies, which demonstrated the conversion of the polyaniline coating to a carbonized structure. X-ray photoelectron spectroscopy proved that the carbonized overlayer contains nitrogen atoms in various covalent bonding states. Transmission electron microscopy confirmed the coaxial structure of the composites. The Brunauer-Emmett-Teller method was used to estimate the specific surface area, the highest being 272 m2 g−1. The conductivity of 0.9–16 S cm−1 was measured by the four-point method, and it was only a little affected by the carbonization of the polyaniline coating.

Photovoltaic properties of multi walled carbon nanotubes - poly(3-octathiophene) conducting polymer blends structures

2013 ◽  
Vol 1493 ◽  
pp. 139-144 ◽  
Author(s):  
Punya A. Basnayaka ◽  
Pedro Villalba ◽  
Manoj K. Ram ◽  
Lee Stefanakos ◽  
Ashok Kumar
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Conducting Polymer ◽  
Photoelectrochemical Cell ◽  
Photovoltaic Properties ◽  
Multi Wall Carbon Nanotubes ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

AbstractIn the present study, we have studied photoelectrochemical properties of poly(3-octathiophene) (P3OT), blending with multi-wall carbon nanotubes (MWCNTs). P3OT blended with MWCNTs was characterized using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Raman spectroscope, and Cyclic Voltammetry (CV) techniques, respectively. The photoelectrochemical current of the MWCNs-P3OT based cell under illumination was investigated by applying a voltage. The blend consisting of 10% MWCNTs in P3OT gave the promising photocurrent in 0.2 M tetra-butyl-ammonium-tetrafluoroborate (TBATFB), electrolyte. Experimental results indicate that photocurrent obtained from MWCNT-P3OT was three times higher than simple P3OT-based conducting polymer. The electrochemical responses of MWCNT-P3OT films in different electrolytes such as 0.2M TBATFB, 0.2 M LiClO4, 1 M H2SO4 and 0.2 M LiBF6 were investigated for comparative photocurrent properties of the photoelectrochemical cell.

Aligned Carbon Nanotubes Via Microwave Plasma Enhanced Chemical Vapor Deposition

1999 ◽  
Vol 593 ◽  
Author(s):  
H. Cui ◽  
D. Palmer ◽  
O. Zhou ◽  
B. R. Stoner
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
Multi Wall Carbon Nanotubes ◽  
Field Emission Properties ◽  
Transmission Electron

ABSTRACTAligned multi-wall carbon nanotubes have been grown on silicon substrates by microwave plasma enhanced chemical vapor deposition using methane/ammonia mixtures. The concentration ratio of methane/ammonia in addition to substrate temperature was varied. The morphology, structure and alignment of carbon nanotubes were studied by scanning electron microscopy and transmission electron microscopy. Both concentric hollow and bamboo-type multi-wall carbon nanotubes were observed. Growth rate, size distribution, alignment, morphology, and structure of carbon nanotubes changed with methane/ammonia ratio and growth temperature. Preliminary results on field emission properties are also presented.

Electrochemical performances of cobalt oxide–carbon nanotubes electrodes via different methods as negative material for alkaline rechargeable batteries

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73410-73415 ◽  
Author(s):  
Yanan Xu ◽  
Yanyin Dong ◽  
Xiaofeng Wang ◽  
Yijing Wang ◽  
Lifang Jiao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cobalt Oxide ◽  
Rechargeable Batteries ◽  
Electrochemical Performances ◽  
Negative Materials ◽  
Negative Material ◽  
First Time

Co3O4/CNTs samples are synthesized via different methods and investigated as negative materials for alkaline rechargeable batteries for the first time.

Sign in / Sign up

Export Citation Format

Share Document