Electrochemical reactions macrokinetics

Electrochemical macrokinetics deals with the combined effects of polarization characteristics and of ohmic and diffusion factors on the current distribution and overall rate of electrochemical reactions in systems with distributed parameters. The term macrokinetics is used (mainly in Russian scientific publications) to distinguish these effects conveniently from effects arising at the molecular level. 

The use of immobilized biocatalysts is likely to bring about certain variations in the macrokinetics of electrochemical reactions, as compared with the case of conventional electrocatalysts which have been analyzed in detail in previous monographs. Linear dimensions of the enzymes are of the order of some hundred A and the area occupied by them at the interface is of the order of a thousand A. The matrix in which the enzymes are immobilized has a thickness of 50-200 /im, which is commensurable with the parameters of the diffusion layer. Furthermore, the specificities of the enzymatic kinetics may exert an effect on the macrokinetic characteristics of the system as a whole. 

The parameter F represents the integral current density for the microstmctuie. At the same time it represents the local current density for the macrostmctuie. Using this parameter and taking Ohm s law into account, the equation describing the secondary macrokinetics (ion transport and electrochemical reaction in the macrostructure) can be written as... 

The overall kinetics or macrokinetics of an electrochemical process with a conversion reaction is determined by the kinetics of several subsequent processes (microkinetics). These involve... 

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