The reduction of oxygen and hydrogen peroxide on dinuclear ruthenium phthalocyanine electrocatalytic surfaces

The electrochemical properties of both mononuclear (L2RuPc)-Pc-II and dinuc lear [(THF)Rupc](2) species are described. The former is dominated by ring oxidation and reduction processes while the latter displays a series of met al localized processes. A Pourbaix diagram describes the various surfaces w hich can be generated by exposing a graphite electrode modified with [(THF) Rupc](2) to aqueous buffer at different polarization over a wide range of p H. The behavior of these various surfaces towards the electrocatalytic redu ction of both oxygen and hydrogen peroxide is described. Most importantly, three different regimes of hydrogen peroxide reduction are observed depende nt on the nature of the modified electrode surface. At high pH the four ele ctron reduction of oxygen to water is observed via a 2 + 2 mechanism.