Multiple-Electron Transfers Adaptive Spatial Grids

Multiple-Electron Transfers Adaptive Spatial Grids 

In the previous chapter we have introduced the case of multiple-electron transfers (multi-E mechanisms). As discussed then, depending on the formal potentials of the different electrochemical steps comproportiona-tion/disproportionation reactions may be thermodynamically favourable and may affect the voltammetry if the electron transfers are not reversible, the diffusion coefficients of the species are different, there is mass transport by migration or other chemical reactions take place. For example, let us consider the case of two consecutive reduction processes (the EE mechanism) where the formal potential of the second step is much more negative than the first one  

When one or more of the conditions mentioned above do not apply, the process (6.29) must be considered for rigorous simulation of the voltammetric response  

The corresponding kinetic-diffusion differential equation system to be solved is non-linear  

After normalisation and discretisation of the above equations, the Newton-Raphson method discussed in the previous section can be employed for the determination of the concentration profiles and the cmrent response that 

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Multiple-Electron Transfers Adaptive Spatial Grids... 

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