Electrocatalysis of H2O2 reduction/oxidation at model platinum surfaces

•Hydrogen peroxide oxidation is affected by surface oxidation at Pt(111) terraces.•The overall reaction can be split in two independent processes.•The reactions are faster at stepped surfaces on less oxidized Pt surfaces.•On PtO surfaces, the reduction reaction is faster at Pt(111).

Oxidation (HPOR) and reduction (HPRR) reactions of hydrogen peroxide were studied on platinum single crystalline surfaces. Experimental curves were fitted to a simple model in which the whole process is described by the sum of two independent, mass controlled reactions. It is shown that stepped surfaces are more catalytic than basal planes for both HPOR and HPRR reactions. On the contrary, on oxide covered surfaces, those having large {111} terraces are better electrocatalysts for HPRR, but worse for HPOR. These results shed light concerning H2O2 reactivity on platinum surfaces and may help to unveil oxygen reduction reaction mechanism.