Electrodes properties

Shi, J., T. Makoto, T. Hiroyuki, N. Kuriyama, and T. Sakai, Influence of carbon on electrode properties of V-Ti-Ni type hydrogen storage alloy, /. Alloys Compd., 293-295, 716-720,1999. 

Li Q, Zhao H, Huo L, Sun L, Cheng X, and Grenier JC. Electrode properties of Sr doped La2Cu04 as new cathode material for intermediate-temperature SOFCs. Electrochem. Commun. 2007 9 1508-1512. 

U sually, there is a significant interdependency between the electrode properties and the electrolyte composition, that is, reactants, products, solvents, and supporting electrolytes, including impurities. 

Dimensions and structures of pores in electrode materials will vary in an extremely wide range. The influence of the porosity on the electrode properties includes also mass-transfer effects. 

Fig. 8.10 Principles of GITT for the evaluation of thermodynamic and kinetic data of electrodes. A constant current Iq is applied and interrupted after certain time intervals t until an equilibrium cell voltage is reached. The combined analysis of the relaxation process and the variation of the steady state voltage results in a comprehensive picture of fundamental electrode properties.

O. Isatd, The dependence of glass-electrode properties on composition. 

A poly (vinylchloride) membrane electrode was described for local anesthetics, based on dibenzo-24-crown-8 as the electroactive material, and di(2-ethyl)hexyl phthalate as the plasticizer [74]. It was reported that the electrode exhibited a Nemstian response to procaine, and other electrode properties were also presented. The analysis was performed at pH 6 to 6.5 vs. S.C.E., with a 0.2 M lithium acetate agar bridge. Less efficient crown ethers studied at this time were benzo-15-crown-5, dibenzo-18-crown-6, and dibenzo-30-crown-10. 

The blocking effect of ben2yl and substituted ben2yl alcohol additives on the electrodeposition of cadmium [220] and stabilization of cadmium electrode properties [221] were studied voltammetrically. 

O Brien. 1235 Ohmic drop, 811, 1089, 1108 Ohmic resistance, 1175 Ohm s law, 1127. 1172 Open circuit cell, 1350 Open circuit decay method, 1412 Order of electrodic reaction, definition 1187. 1188 cathodic reaction, 1188 anodic reaction, 1188 Organic adsorption. 968. 978. 1339 additives, electrodeposition, 1339 aliphatic molecules, 978, 979 and the almost-null current test. 971 aromatic compounds, 979 charge transfer reaction, 969, 970 chemical potential, 975 as corrosion inhibitors, 968, 1192 electrode properties and, 979 electrolyte properties and, 979 forces involved in, 971, 972 977, 978 free energy, 971 functional groups in, 979 heterogeneity of the electrode, 983, 1195 hydrocarbon chains, 978, 979 hydrogen coadsorption and, 1340 hydrophilicity and, 982 importance, 968 and industrial processes, 968 irreversible. 969. 970 isotherms and, 982, 983... 

On this basis it seems that metal properties do affect the total capacity, C, through the changes in M- Thus, the next question seems quite obvious Would it be possible to measure and then corroborate its contribution to the total capacity of the double layer Unfortunately a direct measurement of CM is not possible because the metal will always form part of the total double layer and therefore only the total capacity can be measured. However, we may still have some weapons left. It is possible to obtain an indirect measurement of in the absence of specific adsorption. The way to proceed is as follows. From Eq. (6.124) we see that CH is independent of the concentration in solution, in contrast to the term Qji which involves the term c0 [see Eq. (6.130)]. However, CM should be independent of the concentration of the solution since it involves only the electrode properties. Thus, it is reasonable to combine the concentration-independent terms and say, for example, that the term CM is included in the CH term.48 Thus, a plot of CH vs. the charge of the electrode, qu, would give an indication of the effect of CM on the interfacial properties. Figure 6.70 shows one of those graphs. Thus, the shape of this graph, the asymmetric parabola, is most probably due to the influence of the properties of the metal in the interfacial properties. 

Rapid polymerization of electrochemically generated species such as organic radicals can cover an electrode with a polymeric film. Such films are sometimes impenetrable and difficult to remove, which results in passivation of the electrode surface. A typical case is the oxidation of 1,2-diaminobenzene [9]. The modification of electrode properties by coating with thin polymer films is currently an area of active investigation [10— 12]. 

We have discussed the effects of chemisorption and of electron and hole transport across the semiconductor/electrolyte interface. These have been shown to play a large role in determining electrode properties. Recently another mechanism of... 

Figure 15 shows the spectral response and I-V characteristics for a SrTiO electrode in 1 M KOH after being aged for two days at +5 V vs SCE in 1 M KF. These electrode properties appear constant with respect to operation in a PEC. The quantum efficiency at 0 V vs SCE is substantially improved as is the collec-... 

Of the various types of oxygen pumping sensors, the double-cell devices appear to have the best overall performance characteristics. These devices can be constructed to achieve the best combination of response time, independence of temperature and absolute pressure, insensitivity to electrode properties and operation not limited by the resistance of the Zr02 material. 

The exchange current density is the electrode reaction rate at the equilibrium potential (identical forward and reverse reaction rates) and depends on the electrode properties and operation. The typical expression for determining the exchange current density is the Arrhenius law (3.23), where the constant A depends on the gas concentration. Costamagna et al. [40] provide the following expressions for the anodic and cathodic exchange current density, respectively ... 

Fig. 12.9. A metal can corrode (a) by a heterogeneous mechanism if it contains areas of different electrodic properties or (b) by a homogeneous one if the surface is uniform.

Thin-film electrode — An electrode covered with a thin film of a given substance. The purpose of placing a thin film on the electrode surface is to obtain desired electrode properties. Many different substances have been used to prepare film electrodes they include among others mercury (see - thin mercury film electrodes) gold, boron-doped diamond (see - boron-doped diamond electrode), conductive polymers (see - polymer-modified electrode), and alkanethiols. The film thickness can vary from several micrometers (mercury) to monomolecular layers (thiols). In some cases (e.g., for - spectroelectrochemistry purposes) very thin layers of either gold or tin oxide are vapor-deposited onto glass plates. Thin film electrodes are often called - surface-modified electrodes. 

Deakin and coworkers [647,651 ] analyzed the effect of pH on the redox behavior of the Fe(CN)f, couple and the mechanisms of oxidation of catechols and ascorbic acid at carbon electrodes. They concluded that some [electrode] property other than microscopic area changes or electrostatics plays a role in the observed effects," and suggested that the hydrophobic nature of unactivated surfaces is a major contribution to the observed results. ... 

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