The four components of an electrochemical model

How does one go about constructing such a model Three pieces of information are required to define the experimental system kinetics, mass transport and experimental technique. 

The rate of electron transfer and its potential dependence can be described by the Butler-Volmer equation (20) (see Section 2). An electron transfer often initiates a cascade of homogeneous chemical reactions by producing a reactive radical anion/cation. The mechanism can be described mathematically by a rate equation for each species these form part of the electrochemical model. The rate law of the overall sequence is probed by the voltammetric experiment. 

Each of the three mass transport components may be described mathematically, as discussed in Section 2. The effect of all three modes of mass transport may be summed giving the partial differential equation (PDE) (98), 

The experimental technique controls how the mass transport and rate law are combined (and filtered, e.g. by removing convective transport terms in a diffusion-only CV experiment) to form the overall material balance equation. Migration effects may be eliminated by addition of supporting electrolyte steady-state measurements eliminate the need to solve the equation in a time-dependent manner excess substrate can reduce the kinetics from second to pseudo-first order in a mechanism such as EC. The material balance equations (one for each species), with a given set of boundary conditions and parameters (electrode/cell dimensions, flow rate, rate constants, etc.), define an I-E-t surface, which is traversed by the voltammetric technique. 

If all of these are known, the concentration distributions of the species throughout the experiment may be described mathematically as a set of simultaneous partial differential equations. The way these equations are perturbed during the course of the experiment and the boundary conditions required to solve them may also be deduced from these three pieces of information. 

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