Silver electrode process

Before examining the processes in a cell, we should name the parts of a cell and clear away some language matters. The electrons enter and leave the cell through electrical conductors—the copper rod and the silver rod in Figure 12-5— called electrodes. At one electrode, the copper electrode, electrons are released and oxidation occurs. The electrode where oxidation occurs is called the anode. At the other electrode, the silver electrode, electrons are gained and reduction occurs. The electrode where reduction occurs is called the cathode. 

It is recognized, that the overall process consists of the catalysis of reaction 1, an intermediate step being the reduction of water. Reaction 4 can be treated as hydrogen evolution on a compact silver electrode at negative potential. Silver has a small overpotential for evolution Of the two steps of which reaction 4 is composed... 

Corrigan and Weaver employed the PDIR approach to study the potential-dependent adsorption of azide, N , at a silver electrode. The potential was switched between the reference value, —0.97 V vs. SCE (where adsorption is known to be limited) and the working potential every 30-60 scans, i.e. up to a minute per step, to a total of c. 1000 scans. The high number of scans was required in order to obtain the required S/N ratio hence the PDIR technique was employed to minimise instrumental drift. Since the electrochemical process under study was totally reversible on the timescale of the experiment, the PDIR technique was a viable option. 

Thus, an equation in agreement with the experimental data for the hydroquinone-silver ion reaction can be derived either on the basis of the assumption that adsorption of silver ions by the silver is a prelude to the reaction, or on the basis of the assumption that the rate-controlling step in an electrode process is the rate of transfer of electrons to the silver electrode. The first mechanism carries with it the assumption that a silver ion adsorbed by silver is more easily reduced than an ion in solu-... 

Various problems related to the construction and performances of these batteries, such as changes in materials of membranes and additives both to the electrode materials and to the electrolyte, were studied in recent years. Some instability of the silver electrode during such storage period and the ways of avoiding these difficulties were studied and discussed [347]. Reserve activated silver oxide-zinc cells were constructed [348] with synthetic Ag20 and Pb-treated zinc electrodes were produced by a nonelec-trolytic process. The cells were tested before and after thermally accelerated aging. 

UPD process has also been studied on screen-printed silver electrodes using voltammetric techniques and scanning electron microscope analysis [293]. The relative occurrence of UPD and bulk Pb process has been dependent on the scan rate, with increasing role of UPD process in higher rates. Studies on Pb deposition on silver colloids have pointed to its similarity to bulk electrode [283]. 

Electrode Processes with Participation of Silver Electrodes. 935... 

Bare Ag electrodes. It is noteworthy that the recently studied electrode processes of organic compounds at pc-Ag electrodes involve mainly biochemically important species. For example, Zeng et al. [278] have investigated the voltammetric behavior of 2-mercaptopyrimidine (MPD) and have found that at appropriate potentials, MPD adsorbs on and interacts with the electrode to form an insoluble silver salt at the surface. The first of two cathodic... 

CN ions. Anodic dissolution of silver electrode in cyanide solutions and also the behavior of Ag at potentials preceding dissolution have been studied applying electrode impedance measurements [381]. At potentials of anodic dissolution, the process was represented by the equivalent circuit with two parallel branches. 

A term used to describe how easily a metal is oxidized is active. A more active metal is one that is more easily oxidized. A listing of metals in order of activity is known as an activity series. The activity series is used to determine which substances will be oxidized and reduced in an electrochemical cell the element higher on the list will be oxidized. For example, in a cell with aluminum and silver electrodes in their appropriate solutions, aluminum is oxidized and silver is reduced. Therefore, aluminum is the anode and silver is the cathode. If you have ever bitten a piece of aluminum foil and experienced discomfort, you had this electrochemical process occur in your mouth. Silver (or mercury) fillings and the aluminum serve as electrodes and your saliva serves as an electrolyte between the two. The resulting current stimulates the nerves in your mouth resulting in the discomfort. 

The silver ions used in the bacterial snsceptibility tests were released from pure silver electrodes using a 12 V battery-operated direct cnrrent generator. The apparatus used for silver ion generation was described previonsly in [13]. The water-based silver colloidal solution was obtained by a three-stage process based on the... 

Let s assume that the silver electrode is composed of a thin layer of silver plated on a polished noble metal. Then at the time when all of the silver is stripped, the potential of the electrode will shoot to higher (more positive) territory until the next species in the electrolyte gets oxidized. Suppose this next anodic process is decomposition of water, (d) Calculate the time it takes to raise the electrode potential to oxygen evolution. (Kang)... 

Though not electrode processes, solvents such as DMF and formamide can act as reductants for silver and gold salts.10 Recently the reduction of Ag+ in DMF (HC0NMe2+2Ag++H20 -> 2Ag°+Me2NCOOH+2H+) has been used to form thin... 

The electrode process is a special case of the (Ag" " Ag) couple, except that silver in the +1 oxidation state collects as solid AgCl on the electrode itself. Even solid AgCl, however, has some Ag+ in equilibrium with it in solution. This [Ag+] can be calculated from the KSp equation as follows ... 

At a silver electrode the latter process is facilitated via formation of a Ag1— OH bond the shift in oxidation potential from +2.42 to +0.80 V is a measure of the bond-formation energy (—AGBF) ... 

SERS has also been found to be valuable in characterizing modified electrodes and electrochemical processes (61). SERS was used to observe the sequential electrochemical formation of adsorbed O2-, OH- and H2O on a silver electrode in 0.1-0.001 M alkali chloride solution containing... 

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