Coupling Between the Acid-Base and Redox Equilibria

Coupling Between the Acid-Base and Redox Equilibria 

Besides the dependence of peak potential with solution pH, there is other evidence of the acid-base and redox coupling, namely the prediction of amine deprotonation during film oxidation. Deprotonation is a response to the creation of Os(III) sites that increment the concentration of positive charges in the film. This is an example of charge regulation a chemical equilibrium at the interface is displaced as the system tries to reduce its electrostatic charge. 

It is interesting to find out the optimal conditions for the coupling between redox and acid-base equilibria. To do that, we will look at the variation of the average charged fraction upon oxidation Aox fc), defined as 

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