The influence of Pt-activation on the corrosion of carbon in gas diffusion electrodes. A DEMS study

Abstract Investigations of the dependence on the potential of the anodic oxidation of carbon electrodes using differential electrochemical mass spectroscopy (DEMS) show that pure carbon is oxidized only at potentials higher than 0.9 V (RHE) (with CO2 and, to a lesser extent, CO being the main products), and that Pt activation catalyzes the oxidation of a COsurf surface layer to CO2 at potentials between 0.6 and 0.8 mV (RHE), with the COsurf being formed on the carbon at E>0.3 V (RHE). It is assumed that the Pt-induced carbon corrosion occurs in the neighbourhood of the Pt-sites, thus damaging the Pt to carbon contact. Surface segregation of Pt-clusters and a loss of catalytic activity is the result.