Mechanism of peroxide reactions: the reduction of peroxomonophosphoric acid at a platinum electrode

Abstract

The electrochemical behaviour of peroxomonophosphoric acid has been studied on platinized platinum. The process of electroreduction is irreversible and involves one electron in the rate-determining step. From the dependence of the half-wave potential on the acidity it is concluded that the species H₃PO₅, [H₂PO₅]^–, and [HPO₅]^2– are simultaneously reduced. The electrode reaction is interpreted in terms of a mechanism involving nucleophilic attack by the electrode on the outer peroxidic oxygen of the depolarizer, and mechanistic analogies with the reduction of H₃PO₅ by iodide ion are discussed.