ИСТИНА

The double electric layer structure in various aqueous solutions was earlier studied in details on polycrystalline Au- and Ag- electrodes and individual faces of single-crystal electrodes [1]. Differential capacitances of Au- and Ag- electrodes at large negative charges obtained by different authors differ by more than 1 F/cm2 . This is due to the fact that, in the case of solid metal, several complicating factors manifest themselves: the roughness and crystallographic and energetic nonuniformity of a solid-electrode surface, insufficient reproducibility of its state, the dependence of double electric layer parameters on the surface preparation method, the accumulation of solution impurities at the interface, etc. These factors taken together can yield a large error. All the above problems partly disappear when we pass to electrochemical measurements on renewable electrodes. The surface of such electrodes is subjected in situ (i.e., immediately in solution without interrupting polarization) to the mechanical renewal (by cutting a thin metal layer) [2, 3]. Note that the in situ procedure of mechanical renewal also makes it possible to solve the problem of data reliability very serious for solid electrodes, because allows one to avoid contact between the electrode surface and the atmosphere which is usually the origin of uncontrolled contamination and/or oxidation of the metal surface.