The kinetics of the oxidation and reduction of H2O2 at a Pt electrode: A differential electrochemical mass spectrometric study

Abstract The kinetics of the oxidation and reduction of hydrogen peroxide (HPOOR, HPORR) at a Pt electrode in 0.1 M HClO 4  + 2 mM H 2 O 2 are investigated by Differential Electrochemical Mass Spectrometry (DEMS) in a flow cell. The O 2 mass signal was recorded during cyclic voltammetry, and its potential dependence follows the shape of the cyclic voltammogram. Partial currents for HPOOR and HPORR are estimated based on the O 2 mass signal and the total Faradaic current. The onset overpotential for HPORR at the Pt electrode is above 0.6 V. It is limited by the thermodynamics of OH ad desorption, as is also the case with ORR. The onset overpotential for HPOOR is below 0.1 V, due to the faster consumption of H 2 O 2 through HPORR at these potentials and the small bulk H 2 O 2 concentration used.