Irreversible Electron Transfer and Adsorbed Redox Species

16 Irreversible Electron Transfer and Adsorbed Redox Species 

Problems 7.14 and 7.15 have assumed that the coverages of the reduced and oxidised surface-bound species can be described through the use of the Nernst equation. In the case of a surface-bound species where the electron transfer is slow (irreversible), this approximation no longer holds. 

Note that as we are dealing with an irreversible electron transfer we may ignore the reverse process (i.e. the oxidation of B to A). 

But because the Nernst equation does not apply, we cannot express Fa as a function of t directly. Rather, in order to find the variation in the surface coverage of A with respect to time, it is necessary to solve the following differential equation  

Integration of the right-hand side of this equation is simpler if we make a 

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