Quasi-homogeneous substrate surface approach

In this simplest approach, following the concept of Delahay [3.305, 3.306] and Parsons [3.307], all adsorption sites of S are considered to be energetically equal. It is further assumed that localized adsorption of and desorption of Me Jg takes place 

Assuming y = z (no cosorption or competitive adsorption phenomena), the flux j(t) is related to the overall current density, i, by 

The potential dependence of both terms Aads and ifdes is described by the well-known Butler-Volmer equation [3.308, 3.309]. Both terms involve the exchange current density, s/j g +  

Sign convention cathodic currents are taken to be negative 

39) describes r(E,f) changes under any polarization conditions (small and large signal system perturbation). 

---

Experimental results on the basis of a kinetic approach of Me UPD on quasi-homogeneous substrate surfaces using large and small signal system perturbation techniques are rather rare [3.89, 3.119, 3.214-3.216, 3.313, 3.314]. 

These controversial results on the kinetics of Me UPD processes, obtained on the basis of the simplest approach assuming quasi-homogeneous substrate surfaces, led to the development of a different kinetic model including surface inhomogeneities, gradients of Meads> and surface diffusion as discussed in the following. 

---