Analysis of a complex electrochemical process: The anodic dissolution and passivation of cobalt in H2CO3/HCO3-/CO32- aqueous media near neutral pH

In H2CO3/HCO3-/CO32- solutions, the anodic dissolution and the active–passive transition of cobalt lead to complex electrochemical phenomena. In order to identify each individual process, a numerical method has been developed and used to resolve into single processes the electrochemical behaviour. Indeed, by using a deconvolution method, we have been able to establish the sequence of processes and the involvement of each chemical species at the rotating cobalt electrode surface during potentiodynamic scans in H2CO3/HCO3-/CO32- solutions at pH ranging from 7.65 to 8.30. Moreover, using different convective conditions, we identified the types of controls that govern the dissolution processes. The results presented in this paper improve and confirm theories reported in literature.