Diffusion-convection process oxidant reduction

Normally, if the electron transfer kinetics of oxidant reduction in Reaction (5-1) is very fast so that the diffusion-convection process could not catch up the speed of this electron-transfer process, the oxidant s surface concentration is quickly exhausted to zero, and the obtained Levich plot of /dc,o vs according to Eqn (5.14a) will be a straight line. From the slope (= 0.62nFDQ r / CQ) of the straight line, the parameter either as n, Do, v, or Cq can be estimated if the other three are known. 

In this chapter we consider systems under conditions in which the kinetics of the electrode reaction is sufficiently fast that the control of the electrode process is totally by mass transport. This situation can, in principle, always be achieved if the applied potential is sufficiently positive (oxidation) or negative (reduction). First we consider the case of pure diffusion control, and secondly systems where there is a convection component. 

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