Electrode, copper coated, oxidative

The glass tubes contain mercury and are firmly fixed in the ebonite cover of the cell so that the distance between the electrodes may not change during the experiment. Contact with the platinum electrodes is made by dipping the copper wires of the circuit in the mercury contained in the tubes. The coating of the electrodes with platinum black is carried out in order to inhibit polarization. When examining certain electrolytes, platinized electrodes cannot be used since platinum black may catalyze the decomposition or the oxidation of the electrolyte. The cell is maintained at constant temperature thermostatically, as conductivity increases rather significantly with temperature. 

DSA-02 oxide-coated Ti anode (DSA = Dimensionally Stable Anode) is placed, thus creating a large cathode volume. The effluent solution flows perpendicularly through the electrodes with a typical flow rate of 0.5 dm3 s-1. The flowthrough metal electrodes have an active area approximately 15 times their geometric area. The cell allows air sparging to increase the mass-transfer. The current efficiency is about 40% when the inlet concentration of the metal ions is 150 to 1500 ppm and the concentration at the out-let is about 50 ppm. The cell is currently used for the treatment of recirculated wash-waters from acid copper, copper cyanide, zinc cyanide, zinc chloride, cadmium sulphate, cadmium cyanide and precious metal plating and washwaters from electroless copper deposition. Since the foam metal electrodes are relatively expensive the electrodes... 

Other commonly employed redox electrodes are metals such as copper, cobalt, silver, zinc, nickel, and other transition metals. Some p-block metals such as tin, lead and indium can also function as redox electrodes. However, s-block metals such as magnesium do not make good redox electrodes since the elemental metal is reactive and forms a layer of oxide coating, which leads to poor reproducibility, poor electronic conductivity and electrode potentials that are difficult to interpret, (see Section 3.3.1). 

Komsiyska, L. Tsakova, V. Ascorbic acid oxidation at nonmodified and copper-modified polyaniline and poly-ortho-methoxyaniline coated electrodes. Electroanalysis. 2006, 18, 807-813... 

Most recently, they have developed a cell configuration for the study of modified electrodes that employs, as a working electrode, colloidal graphite deposited onto kapton tape (typical window material). Such an arrangement minimizes attenuation due to the electrolyte solution. They coated the working electrode with a thin film of Nafion (a perfluoro sulfonate ionomer from E. I. DuPont de Nemours, Inc.) and incorporated [Cu(2,9-dimethy-1,10-phenanthroline)2] by ion exchange. They were able to obtain the EXAFS spectra around the copper K edge for the complex in both the Cu(I) and Cu(II) oxidation states. 

Table 22.3 shows the standard electrode potentials of the Period 4 transition metals in their -1-2 oxidation state in acid solution. Note that, in general, reducing strength decreases across the series. All the Period 4 transition metals, except copper, are active enough to reduce from aqueous acid to form hydrogen gas. In contrast to the rapid reaction at room temperature of the Group 1A(1) and 2A(2) metals with water, however, the transition metals have an oxide coating that allows rapid reaction only with hot water or steam. 

PPV-based block copolymers with phenylene oxide units are suitable to detect organic vapors, such as acetone, ethanol, ethyl acetate, hexane, toluene, acetic acid, methanol, and diethyl ether. The device is constructed as gold-coated copper interdigitated electrodes with a gap of 1 mm. No response is detected when the sensors are exposed to air saturated with water. Thus, hirmidity does not affect the performance. 

Several metal oxides (platinum, gold," nickel, copper, ) and cobalt phtalo-cyanine have been employed as surface bound mediators for carbohydrate detection. In a dc amperometric mode of operation detectors based on these mediators exhibit a significant loss of response with time and/or exposure to analyte. Various potential pulse programs have circumvented this stability problem, but at the expense of sensitivity and complexity of the instrumentation. Silver electrodes coated with electrogenerated silver oxide exhibit electrocatalytic activity with respect to carbohydrate oxidation. This paper describes our efforts to utilize an electrode as a carbohydrate detector in a dc amperometric mode. 

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