On the influence of RRC and RSC dimerizations on the shape of semi-integrated voltammograms: a mixed asymptotic and numerical analysis

With the ultimate purpose of determining experimentally whether rate-determ ining adsorption effects are involved in the electroreduction of vinylic mo nomers in electropolymerization synthesis, we have examined whether the dia gnosis of adsorption proposed by Bowling and McCreery is still valid when d imerization reactions (RRC and RSC) are coupled to the charge transfer. The analysis we made in a previous work suggests that maxima are likely to occ ur on systems in which the coupled chemistry directly or indirectly consume s the depolarizer, enough to cause a significant and non-electrochemical de pletion of this compound in the diffusion layer. The overall result of this study is that the RSC scheme is responsible for maxima on the convolved cu rrents in most regions of the kinetic zones diagram even when adsorption ef fects are absent, while the diagnosis remains unconditionally valid for the RRC scheme. The issue as to whether these maxima are detectable experiment ally is also considered. (C) 1999 Elsevier Science Ltd. All rights reserved .