Interfadal lattice transformation

The clean surface of metals in vacuum sustains a surface lattice transformation, as described in Sec. 6.1. Similarly, an interfadal lattice transformation takes place also on metal electrodes in aqueous solutions. In general, the interfadal lattice transformation of metal electrodes is affected by both the electrode potential and the ionic contact adsorption. 

Fig. 6-96. Change in differential capacity of an interfadal double layer leading or not leading to interfadal lattice transformation in anodic and cathodic potential sweeps for a gold electrode surface (100) in perchloric add solution Ey = critical potential beyond which the interfadal lattice transforms from (5 x 20) to (1 x 1) E = critical potential below which the interfadal lattice transforms from (1 x 1) to (5 x 20) Ejm = potential of zero charge VacE = volt referred to the saturated calomel electrode. [From Kolb-Schneider, 1985.]...

Fi . 5-37. Degree of transformation of interfadal lattice (1x1) - (5x20) observed as a function of cathodic potential for a gold electrode with a plane (100) in perchloric add solution A(total) = total interface area A(5x20) s interface area of (5x20) supper lattice. [From Kolb-Schneider, 1988.]... 

Transformation of interfadal lattice has been observed not only on gold metal electrodes but also on other sp-metal electrodes [Kolb, 1993]. In general, on the electrode interface of sp-metals the interfadal lattice of high atomic density vanishes with anion adsorption in anodic polarization and reappears with increasing electron density at the interface in cathodic polarization as shown in Fig. 5-35. 

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