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Proton Exchange Membrane Fuel Cells (Pemfcs)
Published in Xianguo Li, Principles of Fuel Cells, 2005
The application of the catalyst layer on the carbon paper/cloth can be achieved by paint brushing, spraying, screen printing, and so on. Each method of application requires a different formulation of the catalyst particles, PTFE, and ionomer mixture. For example, the mixture is made paste-like before paint brushing, dilute solution with catalyst particle suspension before spraying, and ink-like solution before screen printing. The exact formulation of the mixture is often held confidential for obvious reason. In some projects of demonstrating PEMFC technology feasibility, platinum black is used as catalyst in order to guarantee the reproductibility, the durability, and the high performance of MEAs. In general, carbon-supported platinum such as 10% wt. Pt/C and 20% wt. Pt/C is used as the catalyst. Supported platinum particles can be made much smaller than the platinum black counterparts; particle diameter of 2 nm is easily obtained in carbon-supported form, as compared with 10–50 nm typical for platinum blacks. Such increased platinum dispersion and the effective access of the protons, electrons, and reactant gas to the active sites provide a PEMFC performance with much reduced platinum loadings, as low as 0.4 mg Pt/cm2, an order of magnitude lower than the conventional platinum loadings. The catalyst layer thickness is typically 100μm for 10% Pt/C and 50μm for 20% Pt/C. These thicknesses for the catalyst layer are substantial as oxygen may only penetrate a fraction of the layer thickness due to the limited rate of mass diffusion, hence the catalyst utilization is still fairly low.82
Enhanced corrosion protection of AZ31B magnesium alloy by MgAl-LDHs composite coatings double-doped with imidazolium ionic liquid and sodium dodecylbenzenesulphonate
Published in Corrosion Engineering, Science and Technology, 2023
Yingxue Liu, Huijie Huangfu, Shuai Gao, Xugeng Guo, Li Wang
The corrosion resistance of the AZ31B Mg alloy samples with and without MgAl-LDHs coatings (exposed area: 1 cm2) was measured in 3.5 wt-% NaCl solution by using different electrochemical methods in the electrochemical workstation (CHI660E, Shanghai Chenhua), as presented in previous reports [48]. In the three-electrode cell, saturated calomel electrode, platinum black electrode and AZ31B Mg alloy electrode were used as reference electrode, auxiliary electrode and working electrode, respectively. To achieve a stable status of the system, an open circuit potential (EOCP) test was carried out for 2000 s before the electrochemical measurements. The potentiodynamic polarisation (PDP) curves were explored from −0.5 to 0.5 V vs. OCP with a scan rate of 1 mV s–1. The electrochemical impedance spectroscopy (EIS) was tested using a frequency range from 100 kHz to 10 mHz with an amplitude of 5 mV, and the EIS data were processed by the ZView software.
Effect of nonionic surfactant on micellization thermodynamics and spectroscopic profile of dye-surfactant aggregation
Published in Journal of Dispersion Science and Technology, 2023
Muhammad Babar Taj, Sadia Noor, Tariq Javed, Anaum Ihsan, Ghulam Sarwari, Sobia Jabeen, Tehmina Sharif, Zubera Naseem, Iram Naz, Humaira Iqbal, Naila Ghani
The conductivity of micellar solutions in the absence and presence of dye was observed using Hanna bench conductivity meter (Cond HI-99301) in a temperature range 298–328 K with 10 K increment rate and accuracy was controlled within ±0.5% ±2. The conductivity meter was equipped with an electrode especially coated with platinum black to offset polarization. The instrument has a conductivity range from 0.01 µS to 199.9 mS (cell constant 0.1/cm ± 10%). The electrode was pre-calibrated using potassium chloride solution within a specified concentration range using molar conductivity data.[18–20,22,23,26,27]
Metal Alloy ICF Capsules Created by Electrodeposition
Published in Fusion Science and Technology, 2018
Corie Horwood, Michael Stadermann, Thomas L. Bunn
The counter electrode was a perforated titanium foil rolled into a cylindrical shape. Platinum (platinum black) was electrodeposited to create the high-surface-area anode. The wire cage cathode frame was inserted into the center of the cylindrical counter electrode, which provides a uniform field around each microsphere inside the cage. Alternatively, a platinum or titanium wire could be wound around the outside of the frame of the cage, provided it does not contact the copper cathode wires. A silver/silver chloride reference electrode was placed ~1 cm from the two-electrode assembly during electrodeposition.27