Membrane electrode assemblies blacks

Fig. 16. Fuel cell and X-band microwave resonator for in situ ESR experiments with membrane-electrode assembly (black rectangle) and electrical contacts and gas feeds (from the left).

The catalytic-electrocatalytic reactor consists of a membrane electrode assembly, such as Pt-black/Nafion/Pd/C sandwiched between sheets of porous carbon cloth, housed in a fuel cell assembly. 

Yasuda K, Taniguchi A, Akita T, loroi T, Siroma Z. 2006a. Characteristics of a platinum black catalyst layer with regard to platinum dissolution phenomena in a membrane electrode assembly. J Electrochem Soc 153 A1599-A1603. 

Carbon Black (300 nin) Figure 1. Basic membrane electrode assembly. 

Figure 12.1 Schematic representation of a membrane-electrode assembly of a PEMFC. Platinnm particles and carbon agglomerates are colored in black and dark gray, respectively.

In this work, three membrane electrode assemblies (MEAs) with the same composition of the anode Pt/Ru black layer and different cathode layers were prepared. The cathode layer of the first MEA ( 1) was made using a Pt-black catalyst with 3.6 mg/cm Pt loading on the cathode side. The cathode layer of the second MEA ( 2) consisted of two layers the external Pt-black layer in contact with the gas diffusion layer (2.8 mg/cm ) and the internal Pt/C layer (0.3 mg/cm ) in contact with the membrane. The cathode layer of the third MEA ( 3) was made using carbon-supported Pt/C catalyst from Tanaka Inc. (1.3 mg/cm ). The anode layers were made in a similar way using Pt/Ru-black with 5.0 O.lmg/cm catalyst loading and 10 wt % of Nafion. 

Nafion 117 (purchased from DuPont) was used as electrolyte membrane for the DMFC single cell, which was pretreated in mildly boiling water with 3% H2O2 for 2 hours, then boiled in 2 M H2SO4 for 2 hours. For each treatment the membrane was washed in de-ionized water several times. After these treatments it was stored in water for preparation of membrane electrode assembly (MEA). Johnson Matthey s unsupported Pt black (2mg/cm ) and Pt-Ru... 

Challenges in the Assembly of Membrane Electrode Assemblies for Regenerative Fuel Cells using Pt/C, Iridium Black, and lr02 Catalysts... 

A painting technique was used to fonn electrodes on both sides of SPIES membranes, using ink slurry. This slurry consisted of platinum black, water, and Nafion solution (5 wt%) as binder. Catalyst loading of 5 mg cm" was used. The ink slurry was sonicated to break up the catalyst powder in order to obtain a homogenous distribution. Several layers of the ink were painted on both sides of the membranes. Samples were dried at 80°C under vacuum for 10 h to eliminate aU solvents. Membrane electrode assembly (MEAs) with effective areas of 5 cm were fabricated. 

Fig. 3. Electrochemical measurements on 15.0 wt.% Pt/C catalysts (double impregnation) reduced under H2 during Ih at 200°C, sample C-200-1 (O) and 5h at 450°C, sample C-450-5 (O). (a) COads stripping voltammograms, measurements in H2SO4 1 M at 25°C, sweep rate of 0.02 V s. Curves in grey first CO stripping curves in black voltammogram after 7 consecutive CO strippings, (b) Polarization curves at 70°C for Membrane-Electrode Assemblies with cathode processed with the same catalysts.

Assemble 5 mg (dry weight) of thermostated algae on the Clark electrode by a dialysis membrane and a special O-ring, which have the same dimensions of flow cell. A black cloth protected all. 

Membrane fuel cells have zero-gap electrodes on both sides of the membrane. Typically the electrodes are made of a carbon fiber mat impregnated with platinum on carbon (Pt/C) catalyst. To achieve an extended surface for the gas to be adsorbed and react and to maintain continuity for ionic transport, interpenetration of electrode and membrane is necessary. This is usually accomplished by impregnating the porous electrode with. Nafion solution. One assembly technique is to suspend the Pt/C in Nafion solution by sonication and spray it onto carbon paper. Then the membrane is hot pressed between the two impregnated electrodes [44]. Another approach is to make an aqueous suspension of three powders - Pt/C, carbon black, and PTFE - and spray it onto the carbon paper. Then 5% Nafion solution is applied by spraying or by floating the electrode on the Nafion solution, after which the membrane is pressed between the electrodes [45]. The Nafion solution serves as an adhesive as well as a means of extending the electrolyte into the structure of the porous electrode. 

Figure 3.5 Drawing of a bipolar electrode-separator stack used in Zn/Br RFBs manufactured by RedHow Ltd. (Brisbane, Australia), showing the components (from top to bottom) current collector (grey sheet with red copper strip), membrane separator (brown sheet), bipolar electrode (black sheet), another membrane separator and bipolar electrode, followed by the casing used to house the assembly (Reproduced with kind permission...

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