The electrochemical reduction of oxygen to hydrogen peroxide at the dropping mercury electrode : Part II. Its kinetics at 0.4<=pH<=5.9

Abstract

From experiments in acidic solutions it is shown that though the mechanism found in alkaline and neutral solutions (Part I) remains valid, the rate constant of the protonation step of the superoxide ion becomes pH-dependent. The experimental results can be quantitatively explained on the assumption of simultaneous protonation by water and free protons, the rate constants of electron transfer and protonation by water retaining their value.

Therefore, the kinetics of the reduction of oxygen can be described by four parameters only, in the range 0.4≤pH≤12.5.

The applicability of some other conceivable mechanisms is discussed.