New insights into the hydrogen peroxide reduction reaction and its comparison with the oxygen reduction reaction in alkaline media on well-defined platinum surfaces

The hydrogen peroxide reduction reaction (HPRR) is investigated at pH = 13 on the Pt basal planes and stepped surfaces with (1 1 1) terraces separated by either monatomic (1 0 0) or (1 1 0) steps. A quantitative analysis of the surface structure effect revealed that Pt(1 1 1) is the most active surface and its activity progressively decreases when steps are introduced. Additionally, inhibition of the HPRR is observed at low potentials, which onset potential is governed by the OHads and the point of maximum entropy (pme) of the interphase. Experiments with different rotation rates suggest the formation of an HPRR intermediate linked to the inhibition process, which is more strongly adsorbed on (1 1 0) than (1 0 0) steps. Finally, a comparison of the HPRR and ORR (oxygen reduction reaction) illustrated the important differences for both reactions, which are dependent on the step density. These divergences have been discussed based on adsorbed intermediates and O-2 interactions with the Pt surface. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The HPRR on Pt surfaces was studied at pH = 13, showing that Pt(1 1 1) is the most active surface, but its activity decreases with the introduction of steps. Inhibition of HPRR was observed at low potentials, with the onset potential controlled by OHads and the point of maximum entropy. Experiments with different rotation rates suggested the formation of an HPRR intermediate linked to the inhibition process.