Silver anode

Jeanmaire D L and Van Duyne R P 1977 Part I heterocyclic, aromatic and aliphatic amines adsorbed on the anodized silver electrode J. Electroanal. Chem. 84 1-20... 

The kinetics and mechanism of the growth of anodic silver sulfide films on silver metal in aqueous sulfide solutions has been studied under potentiodynamic conditions [162], The Ag2S film formation was presumed to proceed as... 

Jeanmaire D.L., Vanduyne R.P., Surface Raman spectro-electrochemistry. 1. Heterocyclic, aromatic, and aliphatic-amines adsorbed on anodized silver electrode, J. Electroanal. Chem. 1977 84 1-20. 

Oxidation occurs at the anode. Silver is lower in the activity series than copper. Therefore, the oxidation half-reaction is... 

Jeanmaire, D. L. and Van Duyne, R. P. (1977). Surface Raman spectroelectrochemistry Part I. Heterocyclic, aromatic, and aliphatic amines adsorbed on the anodized silver electrode. J. Electroaml. Chem. 84 1-20. Albrecht, M. G. and Creighton, J. A. (1977). Anomalously intense Raman spectra of pyridine at a silver electrode. J. Am. Chem. Soc. 99 5215-5217. Van Duyne, R. P. (1979). In Chemical and biochemical applications of lasers, Moore, C. B. (Ed.), academia press. New York, pplOl-185,... 

The cyclic voltammograms of all the carbons carrying preadsorbed silver, recorded in dilute nitric acid solution (Fig. 51), exhibit a Ag"/Ag" couple (cathodic wave < +0.4 V and an anodic response in the +0.40-0.60 V potential range), as well as the electroactive quinone/hydroquinone-like surface system ( p, s +0.50 V p.a2 = +0.90 V). The presence of distinctly shaped anodic silver oxidation peaks indicates the partial solution of sorbed (deposited) metal. An almost sixfold higher anodic peak for D—Ox carbon confirms the partially ionic form of the adsorbed silver. 

A fundamental requirement for all coulometric methods is 100% current efficiency that is, each faraday of electricity must bring about chemical change in the analyte equivalent to one mole of electrons. Note that 100% current efficiency can be achieved without direct participation of the analyte in electron transfer at an electrode. For example, chloride ion may be determined quite easily using poten-tiostatic coulometry or using coulometric titrations with silver ion at a silver anode. Silver ion then reacts with chloride to form a precipitate or deposit of silver chloride. The quantity of electricity required to complete the silver chloride formation serves as the analytical variable. In this instance, 100% current efficiency is realized because the number of moles of electrons is essentially equal to the number of moles of chloride ion in the sample despite the fact that these ions do not react directly at the electrode surface. 

Electroplating Objects can be electroplated with a metal such as silver in a method similar to that used to refine copper. The object to be silver-plated is the cathode of an electrolytic cell. The anode is a silver bar or sheet, as shown in Figure 20.23. At the anode, silver is oxidized to silver ions as electrons are removed by the power source. At the cathode, the silver ions are reduced to silver metal by electrons from the external power source. The silver forms a thin coating over the object being plated. Current passing through the cell must be carefully controlled in order to get a smooth, even metal coating. 

Some of the first methods of measuring quantities of electricity involved the use of chemical coulometers. To do this, an electrolytic cell is placed in seri with the sample electrolysis cell so that the same current passes through both. A typical coulometer cell consists of a platinum crucible containing a silver-nitrate solution and a silver anode. Silver metal is deposited on the preweighed platinum crucible and the latter reweighed to determine the amount of electricity passed Q is calculated from Equation 4.10. 

D. L. (eanmaire and R. P. Vanduyne, Sur-fiace Raman Spectroelectrochemistry. I. Heterocyclic, Aromatic, and Aliphatic-Amines Adsorbed on Anodized Silver Electrode,... 

A known volume of seawater is acidified and the carbon dioxide produced is stripped out of the sample by an inert gas. The gas is bubbled through a reagent containing ethanol-amine, which reacts with the carbon dionde to produce hydroxyethylcarbamic add (Eq. (8-26)). The latter is coulometrically titrated by the hydroxide ions generated at the cathode (Eq. (8-27)), and the pH in the reagent solution is monitored colorimetrically through the indicator thymolphthalein. At the anode silver is oddised (Eq. (8-28)). The amount of electrons produced corresponds to the amount of carbon dioxide in the sample and can thus be converted into concentration by dividing by the sample volume. 

Consideration of the consequences of production of anode silver slime due to insoluble impurities. The anodes must remain active and precious metals must be continuously reclaimed from the slime. The cathode product must not be affected detrimentally by inclusions. 

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