Frumkin

An adsorption equation known as the Frumkin isotherm has the form... 

Rehbinder and co-workers were pioneers in the study of environmental effects on the strength of solids [144], As discussed by Frumkin and others [143-145], the measured hardness of a metal immersed in an electrolyte solution varies with applied potential in the manner of an electrocapillary curve (see Section V-7). A dramatic demonstration of this so-called Rehbinder effect is the easy deformation of single crystals of tin and of zinc if the surface is coated with an oleic acid monolayer [144]. 

The Frumkin isotherm can be regarded as a general isotherm from which both the Temkin and Langmuir isotherms can be obtained as special cases. Szklarska-Smialowski and Wieczorek found that the adsorption of various aliphatic compounds (acids, alcohols and amines) on steel in H2SO4 conformed with the Frumkin isotherm. 

FIG. 24 ct-c Isotherms at 22°C for purified alkanesulfonates. The curve is fitted by the Frumkin isotherm. , Sodium n-decanesulfonate x, sodium /i-dodecanesulfonate. 

The parameters of the Frumkin isotherms shown in Fig. 24 are listed in Table 16. 

TABLE 16 Parameters of Frumkin Adsorption Isotherms Depicted in Fig. 24... 

The relevance of the pzc to the structure of the metal/solution interface and its relation to the metal/vacuum situation was first emphasized by Frumkin and Gorodetzkaya in 1928.18 The first compilation of pzc values was prepared by Frumkin in 1933.19... 

The notion of pzc is absent in early textbooks. A table with pzc values for about 10 metals (but for only 5 are reliable values claimed) was given by Parsons in 1954 in the first volume of this series.4 After a more complete attempt by Frumkin in 196520 to compare work function, extensive work on pzc was reported by Perkins and Andersen9 in this series and by Frumkin etal.8 in another series. Compilations of pzc values were also made by Campanella, Trasatti, Frumkin et al., and Frumkin and Petrii14 up to 1979. A book by Frumkin10 devoted entirely to the potential of zero charge was published posthumously in 1979. 

Models have been proposed to reproduce the curves in Fig. 8. Behavior at metal electrodes was discussed by Frumkin and Damaskin in this... 

The EasQ for Hg, as well as for other liquid metals has been obtained using the Lippman electrometer12 (y, E curve method) modified by Gouy, Frumkin, Koening, and others. The principles of the technique and its problems have been extensively described in previous reviews1,10,16 and will not be dealt with further here. 

Frumkin was the first to give a qualitative consideration of the electrochemical properties of pc electrodes.10,20 70 He noted that the charge fixed value of the potential E and this may change the form of the capacitance curve near the diffuse-layer capacitance minimum. Important results were obtained in a pioneering paper by Valette and Hamelin.67 They compared experimental capacitance curves for a pc-Ag electrode and its three basic faces. They found that the capacitance of a pc-Ag electrode can be obtained by the superposition of the corresponding Cj, E curves for individual faces exposed at the pc surface, i.e. 

The electrical double-layer structure at the liquid Ga/H20 interface has been studied by Frumkin and Bagotskaya et al 10,103,120,333-335 pez ... 

The electrical double layer at a pc-Au/H20 interface has been studied mainly by Clavilier and Nguyen Van Huong,213,256,457-464 Hamelin,465 167 Beck et al.,468-470 and others.471 472 Detailed reviews have been given by Frumkin,10 Hamelin,63 and Vorotyntsev.74 Only a few comments will be added here. 

Results for other metals of the Pt-group are due to Frumkin and co-workers8,10,11,14 (Table 22). However, an electrode with the surface renewed in closed circuit has been used by Lazarova767 to study depend linearly on pH with a slope ofca. 55 mV. This has been explained by the adsorption properties of Rh toward H and O, which shift <7-0 to more negative values. Anions have been observed to specifically adsorb on Rh more strongly than on Pt in the sequence... 

The metals of the Pt-group constitute a particular case. Their catalytic activity has long frustrated the determination of the pzc because of interference from adsorbed hydrogen and oxygen. Nevertheless, estimated values of pzc for polycrystalline Pt are included in all compilations in Table 26. However, after the publication by Frumkin and Petrii14 of a summary of pzc values forPt, Rh, Ir, and Pd, no further progress was made for about 20 years until recently UHV techniques of surface preparation have enabled pzc determinations using methods other than the traditional... 

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