Electrochemical oxidation of hydrogen peroxide at platinum electrodes. Part III: Effect of temperature

The electrochemical oxidation of H2O2 at a platinum rotating disc electrode was studied in 0.1 M phosphate buffer at pH 7.26 for the [H2O2] range 0-40 mM, rotation rates 630-10000 rpm and anodic potential +264 to +712 mV vs. Ag/AgCl using staircase potentiometry over the temperature range 5-35 degre es C. The results were interpreted in terms of a surface binding site model involving two modes of product inhibition. Potential- and temperature-inva riant values of the constants for H2O2, H+ and O-2 binding were determined and the rate constants for reduction and the re-oxidation of the binding si te as a function of potential and temperature were evaluated together with the activation energy for the reduction of the binding site. (C) 1999 Elsev ier Science Ltd. All rights reserved.