Electrode kinetics at constant potential

Abstract

Previous theory has been limited to first-order charge-transfer mechanisms, with the added restriction that the electrical work involved in the reaction take place only during the rate-determining step. These restrictions are eliminated here in a new theoretical development which treats generalized higher-order charge-transfer processes coupled with semi-infinite linear diffusion. Approximate solutions of the diffusion problem, valid for small concentration changes, are derived in closed form. These are compared with exact solutions developed numerically. The agreement is good over the range of reaction times most useful for extracting the parameters which characterize the charge-transfer mechanism.