Local reactivity of hydrogen oxidation reaction on heteroatomic junctions investigated by scanning electrochemical microscopy

JOSE LUIS FERNANDEZ; BRITES HELÚ, MARIELA A.

Santa Fe

Congreso; VI San Luis Conference; 2018

The aim of this work is to apply SECM to analyze the complete mechanism of the hydrogen oxidation reaction (hor: H2 2H+ + 2e-) on heterogonous substrates composed by an active metal (i.e. Pt) and an inert metal (i.e. Au) with the goal to sense the local reactivity at the bimetallic junctions in order to detect changes with respect to the mono-metallic substrates. This study was carried out on highly ordered arrays of Pt microelectrodes supported on Au. It was possible to detect changes in the hor kinetic parameters across the interface. On one hand, the shoulder observed in the IT(ES) curves that is characteristic of transition between mechanistic routes appears at lower overpotentials than on Pt, which leads to a sharp increase of the Heyrovsky equilibrium rate measured in the junctionregion.