Graphene Oxide Nanoplate-MnO2 Composites for Supercapacitors

2012 ◽  
Vol 512-515 ◽  
pp. 944-947 ◽  
Author(s):  
Jia Wei Deng ◽  
Huan Pang ◽  
Shao Mei Wang ◽  
Jiang Shan Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Ambient Temperature ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Supercapacitor Electrode ◽  
Scanning Electron

Graphene oxide nanoplate-MnO2composites have been synthesized by oxidizing part of the carbon atoms in the framework of graphene oxide nanoplates at ambient temperature. The composites were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Their microstructures and morphologies have affected their electrochemical properties. Compared with MnO2nanoparticles, the nanocomposite prepared reveals better electrochemical properties as a supercapacitor electrode material.

Preparation and Electrochemical Properties of LaMnO3 Powder as a Supercapacitor Electrode Material

2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Raw Materials ◽  
Sol Gel ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Lanthanum Manganate ◽  
Pure Phase ◽  
Charge Discharge

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.

Zinc Electrodeposition in the Presence of an Aqueous Electrolyte Containing 1-Ethylpyridinium Bromide: Unexpected Oddities

2017 ◽  
Vol 70 (9) ◽  
pp. 1025 ◽  
Author(s):  
Max E. Easton ◽  
Lisa C. Player ◽  
Anthony F. Masters ◽  
Thomas Maschmeyer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Aqueous Electrolyte ◽  
Redox Couple ◽  
Nucleation Process ◽  
Zinc Electrodeposition ◽  
Unusual Behaviour ◽  
Scanning Electron

The reversible electrodeposition of zinc was investigated in an aqueous electrolyte containing zinc bromide (50 mM) and 1-ethylpyridinium bromide ([C2Py]Br, 50 mM) by cyclic voltammetry, chronoamperometry, and scanning electron microscopy. Unusual voltammetric behaviour for the Zn/ZnII redox couple was observed in the presence of [C2Py]Br. Passivation of the redox couple was observed after a single deposition–stripping cycle at switching potentials more negative than −1.25 V versus Ag/AgCl. This unusual behaviour was attributed to the reduction of 1-ethylpyridinium cations to pyridyl radicals and their follow-up reactions, which influenced the zinc electrochemistry. This behaviour was further seen to modify the nucleation process of electrodeposition, which altered the morphology of zinc electrodeposits.

scholarly journals The Preparation and Study of Ethylene Glycol-Modified Graphene Oxide Membranes for Water Purification

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 188 ◽  
Author(s):  
Yang Zhang ◽  
Lin-Jun Huang ◽  
Jian-Guo Tang ◽  
Yao Wang ◽  
Meng-Meng Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Water Purification ◽  
Interlayer Spacing ◽  
Filtration Method ◽  
Vacuum Filtration ◽  
X Ray ◽  
Molecular Separation ◽  
Scanning Electron

In this work, graphene oxide (GO)/ethylene glycol (EG) membranes were designed by a vacuum filtration method for molecular separation and water purification. The composite membranes were characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The interlayer spacing of GO membranes (0.825 nm) and GO/EG membranes (0.634 nm) are measured by X-ray diffraction (XRD). Using the vacuum filtration method, the membrane thickness can be controlled by selecting the volume of the solution from which the membrane is prepared, to achieve high water permeance and high rejection of Rhodamine B (RhB). The membrane performance was evaluated on a dead-end filtration device. The water permeance and rejection of RhB of the membranes are 103.35 L m−2 h−1 bar−1 and 94.56% (GO), 58.17 L m−2 h−1 bar−1 and 97.13% (GO/EG), respectively. The permeability of GO/EG membrane is about 40 × 10−6 L m-1 h−1 bar−1. Compared with the GO membrane, the GO/EG membrane has better separation performance because of its proper interlayer spacing. In this study, the highest rejection of RhB (99.92%) is achieved. The GO/EG membranes have potential applications in the fields of molecular separation and water purification.

ALIGNED MULTIPLE-WALLED CARBON NANOTUBES AS BIOSENSORS BY COLORIMETRIC AND AMPEROMETRIC TECHNIQUES

2005 ◽  
Vol 04 (02) ◽  
pp. 245-252 ◽  
Author(s):  
JING-RU WU ◽  
EDWIN JAHNGEN ◽  
KUANG-PANG LI ◽  
WAN-SUN TSE ◽  
PING CHIANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Cyclic Voltammetry ◽  
Detection Limit ◽  
Linear Response ◽  
Subsequent Reduction ◽  
Covalently Bonded ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Vertically oriented multiple-walled carbon nanotubes (MWCNTs) aligned on a silicon substrate were covalently bonded with horseradish peroxidase (HRP) and used as biosensors or electrodes. The modified platform was investigated with Scanning Electron Microscopy (SEM), UV-Vis spectrophotometer and Cyclic Voltammetry (CV). The enzyme catalyzed reaction and the subsequent reduction of the enzymatic products by the platform were carefully investigated. The assay was done by measuring the absorbance of the dye formed from the reaction product of the substrates (phenol) and 4-aminoantipyrine. From the linear response, phenol can be quantitized in the range from 47 ppm to 750 ppm with a detection limit of 19 ppm (based on S/N = 3). The resulting modified aligned MWCNTs still exhibited enzymatic activities after storage of 13 days. The activity of the attached HRP was also demonstrated electrochemically.

scholarly journals Understanding the degradation mechanism of rechargeable lithium/sulfur cells: a comprehensive study of the sulfur–graphene oxide cathode after discharge–charge cycling

2014 ◽  
Vol 16 (32) ◽  
pp. 16931-16940 ◽  
Author(s):  
Xuefei Feng ◽  
Min-Kyu Song ◽  
Wayne C. Stolte ◽  
David Gardenghi ◽  
Duo Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Degradation Mechanism ◽  
X Ray ◽  
Oxide Cathode ◽  
Lithium Sulfur ◽  
Scanning Electron ◽  
Comprehensive Study

Degradation mechanism of rechargeable lithium/sulfur-graphene oxide cell was studied using scanning electron microscopy and X-ray spectroscopy.

scholarly journals Synthesis and characterization of graphene oxide flakes for transparent thin films

2021 ◽  
Vol 22 (3) ◽  
pp. 595-601
Author(s):  
R.G. Abaszade ◽  
S.A. Mamedova ◽  
F.G. Agayev ◽  
S.I. Budzulyak ◽  
O.A. Kapush ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Indium Tin Oxide ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

We have synthesized large scale, thin, transparent graphene oxide (GO) flakes by Hummer’s method and investigated their suitability for fabrication of transparent nanocomposites. The GO flakes were comprehensively characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy and Differential Scanning Calorimetry (DSC). X-ray diffraction displayed the peak of graphene oxide at 9°degree, which is characteristic peak of GO in agreement with the literature results. Scanning Electron Microscopy images revealed that thin, transparent, flake form GO with 14,8 µm lateral size and 0,31µm thickness were synthesized. The comparison with literature results show that for the first time, our group could synthesize large scale, thin and more transparent GO flakes by simple Hummer’s method using simple dispersed graphite. EDX measurements indicate the formation of layered structure with oxygen containing functional groups. The intensity ratio between D and G peaks in the Raman spectra proves that less defective GO flakes have been synthesized. The solution ability of the synthesized material indicate that high quality GO flakes were synthesized, which make them effective soluble material due to oxygen containing groups formed on the graphene plane during synthesis process.DSC results shows that these flakes are thermally stable till 200°C.  Due to high solubility properties, large scale and transparency they can be very useful in fabrication of high optical transparent nanocompoties for replacement indium tin oxide transparent conductors in solar panels, biomedical applications and microwave absorbers for electromagnetic interference (EMI) environmental protection.

scholarly journals Facile and green synthesis of silver nanoparticle-reduced graphene oxide composite and its application as nonenzymatic electrochemical sensor for hydrogen peroxide

2021 ◽  
pp. 295-308 ◽  
Author(s):  
Jagdish C. Bhangoji ◽  
Srikant Sahoo ◽  
Ashis Kumar Satpati ◽  
Suresh S. Shendage
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Metal Foil ◽  
Reduced Graphene ◽  
Scanning Electron

A simple and environment friendly protocol has been developed for the synthesis of Ag nanoparticles (AgNPs) supported on reduced graphene oxide (rGO) with copper metal foil as reductant. The prepared AgNPs-rGO, nanocomposite was characterized by various analytical techniques such as scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD). The electrochemical performance of the material has been evaluated using cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The average crystallite size of AgNPs is found to be 32.34 nm. The application of prepared electrocatalyst (AgNPs-rGO) as a non-enzymatic sensor is examined through the modified electrode with the synthesized AgNPs-rGO. The sensor showed excellent performance toward H2O2 reduction with a sensitivity of 12.73 µA.cm-2.mM-1, with a linear dynamic range of 1.5 µM – 100 mM, and the detection limit of 1.90 µM (S/N = 3). Furthermore, the sensor displayed high sensitivity, reproducibility, stability and selectivity for the determination of H2O2. The results demonstrated that AgNPs-rGO has potential applications as sensing material for quantitative determination of H2O2.

scholarly journals Microstructure and microwave absorbing properties of reduced graphene oxide/Ni/multi-walled carbon nanotubes/Fe3O4 filled monolayer cement–based absorber

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882288 ◽  
Author(s):  
Yafei Sun ◽  
Min Chen ◽  
Peiwei Gao ◽  
Tianshu Zhou ◽  
Hongwei Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Pore Structure ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

In this article, reduced graphene oxide/Ni/multi-walled carbon nanotubes/Fe3O4 filled paste is synthesized with the aim of developing a novel shielding material. To do so, nano-dispersion presenting homogeneous distribution is made by ultrasonic dispersing technology. Next, the effects of nano-absorbent content on the fluidity, mechanical strength, pore structure, resistivity, and absorbing reflectivity of paste are studied. At the end, the microstructure of composite is uncovered by scanning electron microscopy, Fourier transformer infrared, X-ray diffraction images as well as the pore size distribution and absorbing reflectivity are revealed. The results indicate that a small load of reduced graphene oxide and other nano-absorbents can significantly reduce the fluidity and resistivity of paste, but its pore structure is improved so that its mechanical properties are increased. Scanning electron microscopy images indicate that reduced graphene oxide promotes the increasing and thickening of the cement hydration products as well as the growth of a large number of flower-like and compact bulk crystals. Furthermore, the minimum reflectivity of −10.6 dB is obtained in the range of 2–18 GHz while the effective bandwidth of 16 GHz is obtained when reflectivity is less than −5 dB. This research provides a new pathway for the preparation of monolayer cement–based absorber.

Synthesis, Structure and Properties of Super Fine LiMn2O4

2010 ◽  
Vol 177 ◽  
pp. 9-11 ◽  
Author(s):  
Jie Song ◽  
Bing Xu ◽  
De Xin Huang ◽  
Cai Xia Li ◽  
Qiang Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Electrode Material ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
X Ray ◽  
Size And Morphology ◽  
Scanning Electron

In this paper, super fine LiMn2O4 powder was synthesized by mechanochemical method starting from Li2CO3 and Mn2O3. The structure, size and morphology of LiMn2O4 were explored with X-ray diffraction and scanning electron microscopy (SEM). The electrochemical properties of LiMn2O4 were studied in 2 mol/L (NH4)2SO4 solution. The result showed that pure spinel LiMn204 powder was prepared after 8h grinding with 3.0KW of power and the particle size was about 1µm. Cyclic vohammetry curve indicate LiMn2O4 electrode material has better capacitive performances.

Synthesis and characterization of conducting copolymer of (N 1,N 3-bis(thiophene-3-ylmethylene)benzene-1,3-diamine-co-3,4-ethylenedioxythiophene)

2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Altuğ Kümbül ◽  
Ersen Turaç ◽  
Tuğba Dursun ◽  
Ertuğrul Şahmetlioğlu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nuclear Magnetic Resonance ◽  
Cyclic Voltammetry ◽  
Chemical Structure ◽  
Synthesis And Characterization ◽  
Conductivity Measurements ◽  
Electrochemical Copolymerization ◽  
Scanning Electron

AbstractElectrochemical copolymerization of N 1,N 3-bis(thiophene-3-ylmethylene)benzene-1,3-diamine (TMBA) with 3,4-ethylenedioxythiophene (EDOT) was carried out in a CH3CN/LiClO4 (0.1 M) solvent-electrolyte via potentiodynamic electrolysis. Chemical structure of the monomer was determined by nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopy. The resulting copolymer was characterized by cyclic voltammetry (CV), FTIR, scanning electron microscopy (SEM), and thermogravimetry analyses (TGA). Conductivity measurements of the copolymer and PEDOT (poly(3,4-ethylenedioxythiophene)) were carried out by the four-probe technique.

Sign in / Sign up

Export Citation Format

Share Document