scholarly journals Pt-Amorphous Barium Aluminum Oxide/Carbon Catalysts for an Enhanced Methanol Electrooxidation Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 708
Author(s):  
Tzu Hsuan Chiang ◽  
Wan-Yu Hou ◽  
Jia-Wei Hsu ◽  
Yu-Si Chen
Keyword(s):  
Aluminum Oxide ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Synergistic Effects ◽  
Methanol Electrooxidation ◽  
Pt Catalyst ◽  
Thermal Method ◽  
Active Surface Area ◽  
Maximum Current Density ◽  
Maximum Current

A new type of amorphous barium aluminum oxide was synthesized using a polyol thermal method involving a mixture with Vulcan XC-72 carbon and supported with 20%Pt catalysts to enhance the activity of a methanol electrooxidation reaction (MOR). The maximum current density, electrochemically active surface area (ECSA), and electrochemical impedance spectra (EIS) of the obtained catalysts for MOR were determined. The MORs of barium aluminum oxide with different calcination temperatures and Ba and Al contact ratios were studied. The MOR of the uncalcined amorphous Ba0.5AlOx catalysts prepared with a mole ratio of 2/1 Ba/Al mixed with Vulcan XC-72 carbon and supported with 20%Pt catalyst (Pt-Ba0.5AlOx/C) was enhanced compared with that of 20%Pt-Al2O3/C and 20%Pt/C catalysts due to its obtained largest maximum current density of 3.89 mA/cm2 and the largest ECSA of 49.83 m2/g. Therefore, Pt-Ba0.5AlOx/C could provide a new pathway to achieve a sufficient electrical conductivity, and possible synergistic effects with other active components improved the catalytic activity and stability of the prepared catalyst in MOR.

scholarly journals Ordered SnO2@C Flake Array as Catalyst Support for Improved Electrocatalytic Activity and Cathode Durability in PEMFCs

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2412
Author(s):  
Zhaoyi Yang ◽  
Ming Chen ◽  
Baizeng Fang ◽  
Gaoyang Liu
Keyword(s):  
Electrochemical Impedance ◽  
Proton Exchange ◽  
Pt Catalyst ◽  
Carbon Paper ◽  
Potential Range ◽  
Active Surface Area ◽  
Reduction Peak ◽  
Electrode Structure ◽  
Positive Interaction ◽  
Supported Pt Catalyst

Pt-SnO2@C-ordered flake array was developed on carbon paper (CP) as an integrated cathode for proton exchange membrane fuel cell through a facile hydrothermal method. In the integrated cathode, Pt nanoparticles were deposited uniformly with a small particle size on the SnO2@C/CP support. Electrochemical impedance spectroscopy analysis revealed lower impedance in a potential range of 0.3–0.5 V for the ordered electrode structure. An electrochemically active surface area and oxygen reduction peak potential determined by cyclic voltammetry measurement verified the synergistic effect between Pt and SnO2, which enhanced the electrochemical catalytic activity. Besides, compared with the commercial carbon-supported Pt catalyst, the as-developed SnO2@C/CP-supported Pt catalyst demonstrated better stability, most likely due to the positive interaction between SnO2 and the carbon coating layer.

scholarly journals Computer-based Finite Element Modeling of Insulated Tuohy Needles Used in Regional Anesthesia

2009 ◽  
Vol 110 (6) ◽  
pp. 1229-1234 ◽  
Author(s):  
Meredith B. Cantrell ◽  
Warren M. Grill ◽  
Stephen M. Klein
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Nerve Fiber ◽  
Current Density ◽  
Three Dimensional ◽  
Element Modeling ◽  
Maximum Current Density ◽  
Maximum Current ◽  
Distal Edge ◽  
Computer Based

Background Differences in needle design may impact nerve localization. This study evaluates the electrical properties of two insulated Tuohy needles using computational finite element modeling. Methods Three-dimensional geometric computer-based models were created representing two 18-gauge, insulated Tuohy needles: (1) with an exposed metal tip and (2) with an insulated tip. The models were projected in simulated human tissue. Using finite element methodology, distributions of current-density were calculated. Voltages in the modeled medium were calculated, and activation patterns of a model nerve fiber around the tip of each needle were estimated using the activating function. Results Maximum current density on the exposed-tip needle occurred along the edge of the distal tip; the distal edge was 1.7 times larger than the side edges and 3.5 times larger than the proximal edge. Conversely, maximum current density occurred along the proximal edge of the insulated-tip Tuohy opening; the proximal edge was 1.9 times larger than the side edges of the opening and 3.5 times larger than the distal edge of the opening. Voltages generated by the exposed-tip needle were larger and had a wider spatial distribution than that of the insulated-tip needle, which restricted to the area immediately adjacent to the opening. Different changes in threshold were predicted to excite a nerve fiber as the needles were rotated or advanced toward the modeled nerve. Conclusions The needles displayed different asymmetric distributions of current density and positional effects on threshold. If this analysis is validated clinically, it may prove useful in testing stimulating needles before clinical application.

scholarly journals Polarization Potential Has No Effect on Maximum Current Density Produced by Halotolerant Bioanodes

Energies ◽  
2018 ◽  
Vol 11 (3) ◽  
pp. 529 ◽  
Author(s):  
Muriel González-Muñoz ◽  
Xochitl Dominguez-Benetton ◽  
Jorge Domínguez-Maldonado ◽  
David Valdés-Lozano ◽  
Daniella Pacheco-Catalán ◽  
...  
Keyword(s):  
Current Density ◽  
Polarization Potential ◽  
Maximum Current Density ◽  
Maximum Current

Preparation and Hydrogen Pumping Characteristics of BaCe0.8Y0.2O3-δ Thin Film

2004 ◽  
Vol 835 ◽  
Author(s):  
T. H. Lee ◽  
B. J. Harder ◽  
C. Zuo ◽  
S. E. Dorris ◽  
U. Balachandran
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Current Density ◽  
Applied Voltage ◽  
Spray Deposition ◽  
High Hydrogen ◽  
Maximum Current Density ◽  
Maximum Current ◽  
Very High

ABSTRACTThin films of BaCe0.8Y0.2O3-δ (BCY) were prepared by colloidal spray deposition. Dense, crack-free BCY films having a grain size of 2–7 μm were successfully deposited on NiO/BCY substrates. Electrochemical hydrogen pumping with the BCY films showed that the maximum current density increased with temperature. The maximum current density was sensitive to the moisture in the cathode gas; the value obtained with a dry cathode gas was only half that with a wet cathode gas. A very high hydrogen-pumping current density of 3.4 A/cm2 was measured at 700°C with an applied voltage of 1.5 V.

scholarly journals Electrochemical Behaviour of Chalcopyrite in Chloride Solutions

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 67 ◽  
Author(s):  
Luis Beiza ◽  
Víctor Quezada ◽  
Evelyn Melo ◽  
Gonzalo Valenzuela
Keyword(s):  
Current Density ◽  
Electrochemical Behaviour ◽  
Sweep Rate ◽  
Chloride Ions ◽  
Ferrous Ions ◽  
Maximum Current Density ◽  
Maximum Current ◽  
Density Values ◽  
Current Densities ◽  
Copper Ores

Due to the depletion of oxidized copper ores, it necessitates the need to focus on metallurgical studies regarding sulphide copper ores, such as chalcopyrite. In this research, the electrochemical behaviour of chalcopyrite has been analysed under different conditions in order to identify the parameters necessary to increase the leaching rates. This was carried out through cyclic voltammetry tests at 1 mV/s using a pure chalcopyrite macro-electrode to evaluate the effect of scan rate, temperature, and the addition of chloride, cupric, and ferrous ions. Lastly, the feasibility of using seawater for chalcopyrite dissolution was investigated. An increase in the sweep rate and temperature proved to be beneficial in obtaining highest current densities at 10 mV/s and 50 °C. Further, an increase of chloride ions enhanced the current density values. The maximum current density obtained was 0.05 A/m2 at concentrations of 150 g/L of chloride. An increase in the concentration of cupric ions favoured the oxidation reaction of Fe (II) to Fe (III). Finally, the concentration of chloride ions present in seawater has been identified as favourable for chalcopyrite leaching.

Effect of Current Densities on the Microstructure and Electrochemical Behavior of the Porous β-PbO2 Electrode

2019 ◽  
Vol 956 ◽  
pp. 21-34
Author(s):  
Shi Chuan Wang ◽  
Sheng Chen ◽  
Bu Ming Chen ◽  
Tai Xiang Huang ◽  
Hui Huang ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Surface Morphology ◽  
Oxygen Evolution ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Active Surface Area ◽  
Galvanostatic Polarization

In order to obtain a titanium-based PbO2 electrode with high electrocatalytic activity and good stability, A porous β-PbO2 electrode is prepared by electrodepositing on titanium substrate Sn-Sb-RuOx coating. The surface morphology and phase analysis of the porous β-PbO2 electrode prepared at different current density were investigated by SEM and XRD. Results showed that the current density changes the surface morphology and active surface area of the porous β-PbO2 electrode. When the current density is 2 A/dm2, the surface of the porous β-PbO2 prepared by electrodeposition has a uniform porous morphology with a pore diameter of 50-200 µm with main crystal phase of β-PbO2. Influence of current density on the electrochemical activity of the electrode was analyzed using anodic polarization curve, electrochemical impedance spectroscopy and galvanostatic polarization. Results revealed that with the increase of current density, the oxygen evolution potential of the porous β-PbO2 electrode decreases first and then increases while the exchange current density first increases and then decreases. When the current density is 2 A/dm2, the oxygen evolution potential is 2.0075 V(at 0.05 A/cm2) and the maximum exchange current density is 1.77×10-4 A/cm2. According to the electrochemical impedance spectroscopy, when the current density is 2 A/dm2, Qf and Qdl are the largest, Rf and Rct are the smallest, and the RF first increases and then decreases with the current density increases. When the current density is 2 A/dm2, the maximum RF value is 655.7. The results with galvanostatic polarization at current density of 0.05 A/cm2 showed that the electrode has a minimum electrode voltage of 2.05 V at a current density of 2 A/dm2. Accelerated life experiments were carried out in 2 g/L Cl- and 150 g/L H2SO4 bath at 25 °C, and the porous β-PbO2 electrode obtained under the current density of 2 A/dm2 has the longest life, and the electrode life is 68 h, which is 2.5 times of the PbO2 electrode obtained under the current density of 4 A/dm2.

An Integrated Maximum Current Density Approach for Noninvasive Detection of Myocardial Infarction

2018 ◽  
Vol 22 (2) ◽  
pp. 495-502 ◽  
Author(s):  
Chen Zhao ◽  
Shiqin Jiang ◽  
Yanhua Wu ◽  
Junjie Zhu ◽  
Dafang Zhou ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Current Density ◽  
Noninvasive Detection ◽  
Maximum Current Density ◽  
Maximum Current
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