Cathode disk design

One important application of amperometry is in the construction of chemical sensors. One of the first amperometric sensors to be developed was for dissolved O2 in blood, which was developed in 1956 by L. C. Clark. The design of the amperometric sensor is shown in Figure 11.38 and is similar to potentiometric membrane electrodes. A gas-permeable membrane is stretched across the end of the sensor and is separated from the working and counter electrodes by a thin solution of KCl. The working electrode is a Pt disk cathode, and an Ag ring anode is the... 

For these reasons, the cathodic corrosion protection of chemical plant parts is restricted to neutral solutions, service water, and alkalis. Various types of anodes are available for the protection of container interiors. Platinized disk electrodes, bar anodes, and titanium basket anodes are used. They are now supplied ready for installation and are designed in such a way that, in continuous operation, they can emit 8-10 A at a current density of 6-8 A/dm. ... 

The sentiment of the design team was to avoid using option 3, the cathode insulator disk, because of the additional development effort required to implement this technique, and the cost of conversion of all 26,400 cathodes in the cellhouse. 

Now, the overpotentials are approximated sis t = j. - E, rfo = (f>o Eeorr o due to Eeorr 0 sincc the pipeline is designed against corrosion. Thus, these assumptions lead to the cathodic protection attenuation equation known as Uhlig s equation for an infinite pipeline which is compared with the disk model equation in mathematical and graphical form (Figure 8.13)... 

A cross-sectional view of the oxygen electrode is given in Figure 1. The electrode has an anode(A) of silver tubing(about 150 mm in length and 10 mm in diameter) and a platinum disk(about 5 mm in diameter) as cathode(F). The electrode is sheathed by an outer tube of stainless steel(B). An electrolyte solution(0.5N KCl aqueous solution) partially fills the annular space(C). The electrode was designed for easy change of membranes, to ensure favorable contact between the cathode and the membrane which is at the end of the outer tube, and to permit measurements on water-swallen membranes. Prior to each run, the cathode was polished to minimize contamination. 

The first glucose BFC implanted in a live animal was reported by Cinquin et al. in 2010 [65]. They designed a glucose bioelectrode based on composite graphite disks containing GOx and ubiquinone at the anode and polyphenol oxidase (PPO) and quinone at the cathode. Their BFC was implanted in a rat and produced apeak specific power of 24.4 pW cm , reportedly greater than the power required to operate a pacemaker. 

Sealless planar Electrochemical cells made up of electrolyte, cathode, and anode are stacked with metal interconnects without using sealing materials. For example, disk-type planar sealless stacks have been constructed by Mitsubishi Materials Corporation. For this purpose, fuel and air are introduced through the central part of the respective cells. Outside the cells, the remaining fuel becomes combusted with air. Self-supporting cells are usually used for this design. 

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