scholarly journals Carbon Nanotubes Generated from Polyphenyl Acetylene

2016 ◽  
Vol 3 (1) ◽  
pp. 11 ◽  
Author(s):  
B. Rajesh ◽  
S. Karthikeyan ◽  
J.-M. Bonard ◽  
K. Ravindranathan Thampi ◽  
B. Viswanathan
Keyword(s):  
Carbon Nanotubes ◽  
Pore Diameter ◽  
Composite Electrode ◽  
Average Particle Size ◽  
Outer Diameter ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Alumina Matrix ◽  
Alumina Membrane ◽  
Ru Nanoparticles

<p>The carbonization of polyphenyl acetylene in alumina matrix yields uniform, cylindrical, monodisperse carbon nanotubes with outer diameter almost equal to pore diameter of the alumina membrane used. The<br />electrochemical characteristics reveal that the charge transfer at the composite electrode based on carbon nanotube might be higher compared to that of planar graphite, glassy carbon and composite electrode based on commercially available Vulcan XC72R carbon. Pt-Ru nanoparticles are highly dispersed inside the tube with an average particle size of 1.7 nm as revealed by HR-TEM images. </p>

scholarly journals Commercial Cokes and Graphites as Anode Materials for Lithium - Ion Cells

1997 ◽  
Vol 496 ◽  
Author(s):  
David J. Derwin ◽  
Kim Kinoshita ◽  
Tri D. Tran ◽  
Peter Zaleski
Keyword(s):  
Electron Microscopy ◽  
Ethylene Carbonate ◽  
Average Particle Size ◽  
Chemical Properties ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Bet Surface Area ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Wide Range

AbstractSeveral types of carbonaceous materials from Superior Graphite Co. were investigated for lithium ion intercalation. These commercially available cokes, graphitized cokes and graphites have a wide range of physical and chemical properties. The coke materials were investigated in propylene carbonate based electrolytes and the graphitic materials were studied in ethylene carbonate / dimethyl solutions to prevent exfoliation. The reversible capacities of disordered cokes are below 230 mAh / g and those for many highly ordered synthetic (artificial) and natural graphites approached 372 mAh / g (LiC6). The irreversible capacity losses vary between 15 to as much as 200 % of reversible capacities for various types of carbon. Heat treated cokes with the average particle size of 10 microns showed marked improvements in reversible capacity for lithium intercalation. The electrochemical characteristics are correlated with data obtained from scanning electron microscopy (SEM), high resolution transmission electron microscopy (TAM), X - ray diffraction (XRD) and BET surface area analysis. The electrochemical performance, availability, cost and manufacturability of these commercial carbons will be discussed.

An Integrated Sonication Technique for Electrodeposition of Platinum and Ruthenium on Carbon Nanotubes for Methanol Oxidation

2012 ◽  
Vol 9 (4) ◽  
Author(s):  
Tsung-Kuang Yeh ◽  
Yu-Ming Chang ◽  
Chuen-Horng Tsai ◽  
Ming-Chi Tsai ◽  
Mei-Ya Wang
Keyword(s):  
Carbon Nanotubes ◽  
Sulfuric Acid ◽  
Methanol Oxidation ◽  
Cyclic Voltammogram ◽  
Electrochemical Characteristics ◽  
H2so4 Solution ◽  
Peak Current Density ◽  
Surface Distribution ◽  
Ru Nanoparticles ◽  
Sonication Technique

An electrodeposition technique that could significantly improve the deposition of platinum-ruthenium (Pt-Ru) nanoparticles onto carbon nanotubes (CNTs) directly grown on carbon cloths was adopted in this study. Integrated sonication (IS) was activated during the electrodeposition process conducted in a sulfuric acid (H2SO4) solution containing Pt and Ru precursor chemicals of hexachloroplatinic acid and ruthenium trichloride, respectively, and ethylene glycol (EG) as a dispersing agent. In comparison with our earlier work, this new technique would further reduce the size of Pt-Ru particles from 4-6 nm to 2-3 nm and lead to a more even and higher surface distribution of these nanoparticles on the CNTs. In addition, the loadings of Pt and Ru on the CNTs were both markedly increased. Electrochemical characteristics of methanol oxidation on specimens bearing these catalysts (Pt-Ru/CNTs) were investigated via cyclic voltammetry analysis in mixed 1 M methanol and 0.5 M sulfuric acid solutions. It was found that the peak current density of methanol oxidation obtained from the cyclic voltammogram on the new Pt-Ru/CNTs specimen was nearly three times of that on the specimen prepared with EG in the absence of IS. The outcome signified better catalyst morphology and distribution and a significantly improved methanol oxidation efficiency of the new specimen prepared in the mixed EG and H2SO4 solution by electrodeposition in the presence of IS.

scholarly journals Evolution of microstructure and electrochemical corrosion characteristics of cold compacted magnesium

2017 ◽  
Vol 61 (4) ◽  
pp. 123-130 ◽  
Author(s):  
M. Březina ◽  
P. Doležal ◽  
M. Krystýnová ◽  
J. Minda ◽  
J. Zapletal ◽  
...  
Keyword(s):  
Degradation Mechanism ◽  
Compaction Pressure ◽  
Average Particle Size ◽  
Light And Electron Microscopy ◽  
Electrochemical Corrosion ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
Modern Approach ◽  
Magnesium Powder ◽  
Compacting Pressure

Abstract The main advantage of magnesium and its alloys is high specific strength and biocompatibility. A modern approach to magnesium-based materials preparation is powder metallurgy. This technique allows preparation of new materials with a unique structure, chemical composition, and controlled porosity. In this study, cold compaction of magnesium powder was studied. Magnesium powder of average particle size of 30 μm was compacted applying pressures of 100 MPa, 200 MPa, 300 MPa, 400 MPa and 500 MPa at laboratory temperature. Influence of compacting pressure was studied with microstructural and electrochemical corrosion characteristics analysis. The resulting microstructure was studied in terms of light and electron microscopy. Obtained electrochemical characteristics were compared with those of wrought magnesium. Compacting pressure had a significant influence on microstructure and electrochemical characteristics of prepared bulk magnesium. With the increase in compaction pressure, the porosity decreased. Compacting pressures of 300 MPa, 400 MPa and 500 MPa led to the similar microstructure of the prepared material. Polarization resistance of compacted magnesium was much lower and samples degraded faster when compared to wrought magnesium. Also, the corrosion degradation mechanism changed due to the microstructural differences between the material states.

The Impregnating Reduction Method for Synthesis of Pt–Ru Nanoparticles and Its Catalytic Performance for Methanol Electro-oxidation

2015 ◽  
Vol 12 (4) ◽  
Author(s):  
Long-long Wang ◽  
Hong-min Mao ◽  
Xiao-jin Zhou ◽  
Qun-jie Xu ◽  
Qiao-xia Li
Keyword(s):  
Reduction Method ◽  
Average Particle Size ◽  
Catalytic Performance ◽  
Average Particle ◽  
X Ray ◽  
Onset Potential ◽  
Ru Nanoparticles ◽  
Oxidation Of Methanol ◽  
Transmission Electron ◽  
Electro Oxidation

Well-dispersed and low Pt content Pt–Ru/C nanoparticles were prepared by a developed impregnating reduction method with sodium citrate as stabilizer. The as-prepared Pt–Ru/C catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. TEM showed that the Pt–Ru particles were quite uniformly distributed on the surface of the carbon with an average particle size of 3.5–4.5 nm. The effect of pH values on methanol electro-oxidation reaction was examined by cyclic voltammetry (CV) and chronoamperometry (CA). Pre-adsorbed CO monolayer stripping was used to evaluate the antipoisoning ability. The results showed that Pt–Ru/C (pH = 8) catalyst had the highest catalytic activity and stability toward the oxidation of methanol. Finally, comparing Pt–Ru/C (Pt–Ru 20 wt.%, Pt/Ru = 1:1) catalysts with Pt/C (Pt 20 wt.%), the onset potential was 200 mV lower and electrochemical active area was much bigger.

PREPARATION AND CHARACTERIZATION OF SiO2 NANOPARTICLE AND MESOPOROUS SILICATE MOLECULAR SIEVE MCM-48

2002 ◽  
Vol 01 (05n06) ◽  
pp. 539-543
Author(s):  
KYUNG WON SEO ◽  
SUNG DU MOON ◽  
YOUNG SOO KANG ◽  
YONG JOO KIM
Keyword(s):  
Particle Size ◽  
Molecular Sieve ◽  
Pore Diameter ◽  
Average Particle Size ◽  
Mesoporous Molecular Sieve ◽  
Average Particle ◽  
Narrow Size Distribution ◽  
Sem Image ◽  
Mesoporous Silicate

Nanosize SiO 2 particles with narrow size distribution were produced by modified Stober–Fink–Bohn method. Average particle size was determined as 170 nm by SEM image. Organosilica mesoporous molecular sieve (MCM-48) was synthesized. The calcined MCM-48 has pore diameter of 26.8 Å and a surface area of 1024 m 2 g -1 by BET (Brunauer–Emmet–Teller) measurement.

scholarly journals Synthesis and Characterization of Cu2FeSnSe4 Nanofilms

2021 ◽  
pp. 1873-1878
Author(s):  
Omar Abdulsada Ali ◽  
Sarmed S.M. Al-Awadi
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Photovoltaic Applications ◽  
Tem Transmission Electron Microscopy

Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application in photovoltaic applications.

SYNTHESIS AND ELECTROCATALYSIS APPLICATION OF HYBRID PLATINUM/CERIUM OXIDE/MULTI-WALLED CARBON NANOTUBES

2011 ◽  
Vol 04 (03) ◽  
pp. 295-298 ◽  
Author(s):  
CHENG HAN CHEN ◽  
YUH-JING CHIOU ◽  
WEI JEN LIOU ◽  
WEI SYUAN LIN ◽  
HONG MING LIN ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cerium Oxide ◽  
Average Particle Size ◽  
Pt Nanoparticles ◽  
Pt Catalyst ◽  
Average Particle ◽  
Redox Peak ◽  
Multi Walled Carbon Nanotubes ◽  
Electro Oxidation ◽  
Walled Carbon Nanotubes

The hybrid nanomaterials of platinum/cerium oxide/multi-walled carbon nanotubes ( Pt/CeO2 /MWCNTs) are synthesized successfully via impregnation and polyol processes. MWCNTs serve as an excellent supporter where CeO2 nanoparticles are decorated with well-distributed Pt nanoparticles. Images show the average particle size of crystalline Pt and CeO2 on MWCNTs are 3–7 and 20–30 nm, respectively. In electrochemical reaction, the redox peak of Pt/CeO2 -700°C/MWCNTs reveals lower potential and higher current density in methanol electro-oxidation than those of other Pt -based ones. The study indicates that the cerium oxide in Pt/CeO2 -700°C/MWCNTs catalyst will enhance significantly the oxygen ions transportation between the interface of Pt and MWCNTs to eliminate the CO poison effect on Pt catalyst.

Preparation of Low Pt-Decorated Ru/C Catalyst and Electrochemical Research

2010 ◽  
Vol 152-153 ◽  
pp. 1620-1623 ◽  
Author(s):  
Qun Jie Xu ◽  
Xiao Jin Zhou ◽  
Qiao Xia Li ◽  
Jin Guang Li ◽  
Yu Zeng Zhao
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Hydrogen Atmosphere ◽  
Average Particle ◽  
Deposition Method ◽  
Spontaneous Deposition ◽  
Catalytic Activities ◽  
Oxidation Current ◽  
Ru Nanoparticles ◽  
Surface Oxides

The Ru/C nanocomposites with loading of 20wt% were prepared by ethylene glycol in the presence of XC-72. Carbon-supported Ru nanoparticles were decorated with Pt by spontaneous deposition method after Ru surface oxides were reduced in the hydrogen atmosphere at 180 for 2h. TEM indicated that the average particle size of catalyst was about 4nm with excellent dispersion and the XRD analyzing results showed that Pt had decorated on surface of Ru. The anti-poisoning ability was studied by pre-adsorbing CO striping voltammetric curves in 0.1M HClO4. Catalytic activities of the prepared Pt/Ru/C were studied by cyclic voltammetry in a solution of 0.5 mol/L CH3OH + 0.1 mol/L HClO4. The results showed that the oxidation current density was far more than 60wt% RuPt/C (E-TEK) and 20wt% Pt/C (Johnson Matthey). At the same time, the study also showed that the prepared catalyst not only had a higher catalytic activity to methanol, but also had lower Pt loading.

Desalination mechanism of modified activated carbon/carbon nanotubes composite electrode

2019 ◽  
Vol 19 (7) ◽  
pp. 2054-2060
Author(s):  
Wang Li ◽  
Hu Yusha ◽  
Lu Yifei ◽  
Fu Jiangtao ◽  
Hu Ning ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Composite Electrode ◽  
Electrochemical Characteristics ◽  
Order Kinetic ◽  
Capacitive Deionization ◽  
Modified Activated Carbon

Abstract Modified activated carbon/carbon nanotubes (AC*/CNT*) composite electrode was used as the electrode in a capacitive deionization (CDI) process for desalination in this study. The morphology and electrochemical characteristics of the modified electrode were discussed, and the results showed that after modification, the specific surface area of AC* reached 672.48 m2/g, increased by 29.43%; while the specific surface area of CNT* was 117.39 m2/g, reduced by 9.94% due to the strong oxidation of the mixed acid, the pore volume of CNT* increased by 48.28%. The electrode regeneration test proved that the electrode had good cycling stability. The pseudo-first-order kinetic model could better describe the adsorption rate of the electrodes for ions and the desalination ratio of the AC*/CNT* electrode reached 7.11 mg/g; the Langmuir model could well describe the adsorption mechanism of capacitive deionization, and indicated that the adsorption process of CDI was near to single ion layer adsorption; the change trend of electric mobility with migration time could be well fitted by exponential equations. This study explored a novel composite electrode coating, and initially explored the behavioral characteristics and trends of CDI technology.

scholarly journals Immobilization of Nuclear Waste Using Carbon Nanotubes Prepared by Laser Ablation in Liquid Method

2021 ◽  
Vol 19 (49) ◽  
pp. 32-41
Author(s):  
Thuraya Amer Abed al-hussein ◽  
Ghufran S. Jaber
Keyword(s):  
Carbon Nanotubes ◽  
Nuclear Waste ◽  
Wave Length ◽  
Average Particle Size ◽  
Beta Radiation ◽  
Average Particle ◽  
Laser Ablation In Liquid ◽  
Before And After ◽  
Sem Micrograph ◽  
Standard Card

In an attempt to disposal from nuclear waste which threats our health and environments. Therefore we have to find appropriate method to immobilize nuclear waste. So, in this research the nuclear waste (Strontium hydroxide) was immobilized by Carbon nanotubes (CNTs).  The Nd-YAG laser with wave length 1064 nm, energy 750 mJ and 100 pulses used to prepare CNTs. After that adding Sr(HO)2 powder to the CNTs colloidal in calculated rate to get homogenous mixing of CNTs-Sr(OH)2. The Sr(HO)2 absorbs carbon dioxide from the air to form strontium carbonate so, the  new solution is CNTs-SrCO3. To dry solution putting three drops from the new solution on the glass slides. To investigate the radiation damage on CNTs structure, the sample was irradiation by Beta source (90Sr/90Y) for different period of time. The structure properties were measured using X-ray diffraction XRD while the shape and size property was measured by scanning electron microscope SEM. The result shows homogenous distribution of nanoparticles with average particle size about 20nm. The XRD spectra for all sample before and after irradiation shows the higher peaks that it’s almost appearance at 2  = 25 degree and when compared the XRD phase with Standard card the resultant nanomaterial is Strontium carbonite (SrCo3). From SEM micrograph, CNTs-SrCO3 were well decorated on the surface of CNTs and there was not any remarkable difference in the corresponding due to Beta radiation exposure.

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