Multielectrode cells

Figure 3. Electrical connections in multielectrode cells, (a) Monopolar, (b) Bipolar...

A muitielectrode photoelectrochemlcal ceil for unassisted photocatalysis and photosynthesis, and incorporating a bipolar T102/Pt multielectrode cell with five panels has been described. It has been used for unassisted photolysis of H2O and produces an H t 0 molar ratio of 2.4 1. In a new induced junction solar cell a strong inversion layer is induced by an external bias voltage across an insulating layer. Its... 

There are two types of multielectrode reactor monopolar and bipolar cells, as shown in Fig. 15.2. The bipolar configuration has the advantage that the electrical circuit has only to be linked at the ends of the electrode pile the disadvantage is limitation to certain electrode materials when the anode and cathode are of the same material or when they can be easily glued to each other. 

Andreescu, S. Sadik, O. A. McGee, D. W., Autonomous multielectrode system for monitoring the interactions of isoflavonoids with lung cancer cells, Anal. Chem. 2004, 76, 2321-2330... 

Figure 1.3 Working electrode designs for external reflectance SEC cells, (a) Single element, (b) temperature controlled, " and (c) multielectrode assembly. ...

Figure 1.14. The outer casing of the cell is constructed from stainless steel and the IR beam enters and departs through a 7-mm thick Cap2 window. The solution is contained by a Teflon insert and this is fashioned so as to minimise the volume required for operation. The connections to the electrodes are most easily managed if a multielectrode assembly is used.

Figure 1.14 Cross-sectional (a) and top (b) schematic views of an external reflection SEC cell suitable for operation at gas pressures to 1 MPa. The details of the multielectrode assembly are shown in Figure 1.3(c).

There is also an increasing interest for developing practical electrode systems for impedance-based monitoring of cell growth and other cellular processes in chambers or scaffolds. Examples are Lu et al. (2013), who used a multielectrode bioimpedance system... 

Some commercially available electrochemical impedance test systems have the ability to measure not only the overall impedance of a complete electrochemical cell, but also the impedance contribution of various component parts of the cell allowing, for example, direct comparison of different anode or cathode materials in a battery. Multielectrode measurement techniques may also be used to investigate individual cells in a battery or fuel cell stack (Figures 3.2.6 and 3.2.7). 

As mentioned in Section 5.2, commercial scale reactors contain modules of multielectrode units. Scaling down for tests is done by reducing a cell stack to one or two electrode pairs. Preliminary tests may use geometrically scaled-down versions. This brings out facets of reactor design associated with scale-up. Problems that may arise are current distribution and mass transfer rates these are dealt with later in this chapter. The design procedure... 

Figure 12.10. Component of array fuel cell array flow field (center), clockwise from upper right array MEA, graphite flow field sensor, counter electrode flow field, and assembled cell with multielectrode potentiostat [15]. (Reprinted, with permission, from the Annual Review of Materials Research, Volume 33 2003 by Annual Reviews www.annual reviews.org.)...

The use of multielectrode BCD in combination with SPE using Ci8 material and HPLC separation was described for the identification of 27 phenolic compoimds in water samples [64]. The multielectrode consisted of four coulometric array cells, each containing four electrochemical detector cells. These employed porous graphite-working sensors with palladium as reference and coimter electrodes were arranged in series after the analytical column. Tap water and mineral water were analyzed the authors reported very low detection limits for the phenols. 

Reiter et al. [15] have reported a multielectrode system that is compatible with the format of standard 96-well microplates. The system, housed in a Faraday cage, is capable of sequentially monitoring, by cyclic or differential pulse voltammetry, the contents of 16 wells, using three-electrode cells with Pt working electrodes. The authors used this system to optimize conditions for redox modification of pyrroquinolinequinone-dependent glucose dehydrogenase with a ruthenium complex for enhanced electrochemical properties. 

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