Electrochemical oxidation of hydrogen peroxide at platinum electrodes. Part IV: Phosphate buffer dependence

The electrochemical oxidation of H₂O₂ at platinum rotating disc electrodes and microelectrodes was studied as a function of phosphate buffer concentration in the range 0-100 mM and pH from pH 4 to pH 10. The results were interpreted in terms of development of a surface binding site for H₂O₂ from a precursor site through interaction with H₂PO₄^- from the electrolyte. In the absence of phosphate an alternative binding site mechanism was evident. The precursor site was shown to be inhibited by protons at low pH producing an inactive site.