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Considerations of the pH dependence of hydrous oxide films formed on iridium by voltammetric cycling
Author(s) -
Hitchman Michael L.,
Ramanathan Subramaniam
Publication year - 1992
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140040306
Subject(s) - iridium , electrochemistry , oxide , electrode , inorganic chemistry , chemistry , proton , population , cycling , electron , analytical chemistry (journal) , materials science , catalysis , environmental chemistry , biochemistry , physics , demography , organic chemistry , quantum mechanics , archaeology , sociology , history
The electrochemical behavior and the analytical utility of hydrous oxide films, formed on iridium by voltammetric cycling, have been studied by evaluating the dependence of the apparent Standard Electrode Potential ( E °′) and the ratio of protons to electrons (p/e) participating in the potential determining equilibria on the charge storage capacity. A model based on electron exchange involving protons in solution and conductive sites on the hydrous oxide surface is proposed and it is shown that an increase in population of the conductive sites can be correlated with an enhancement in proton exchange capacity. The influence of the pretreatment is shown to be an important factor in determining both E °′ and p/e. The implications of these results for the use of hydrous iridium oxide electrodes as potentiometric pH sensors are considered.