Electrochemical irreversibility:
The electrochemical irreversibility is caused by slow electron exchange of the redox species with the working electrode.
The electrochemical irreversibility is caused by slow electron exchange of the redox species with the working electrode. The procedure is said to be quasi-reversible if it is reversible at low sweep rates other than becomes irreversible at higher ones after having passed by a region known as quasi-reversible at intermediate values. That transition from reversibility occurs while the associative rate of electron transfer along with respect to which of mass transport is insufficient to maintain Nernstian equilibrium at the electrode surface. Within the quasi-reversible region, both forward and backward reactions make a contribution to the observed current.
Peak separation greater than the predicted theoretical value (59/n mV) is typically caused by IR drop due to high resistance between working and reference electrodes. This is especially a problem at fast scan rates where 'I' can be large and in non- aqueous solvent where 'R' can be large. Also, slow heterogeneous electron exchange with the electrode can increase Ep.