On the mobility of carbon-supported platinum nanoparticles towards unveiling cathode degradation in water electrolysis

Abstract This study investigates the influence of the hydrogen evolution reaction (HER) overpotential on the mobility of carbon-supported platinum particles. The migration of the platinum over the carbon support was analyzed by means of identical location transmission electron microscopy (IL-TEM). While at potentials of 0.1 and 0 V vs. reversible hydrogen electrode (RHE), no changes to the Pt/C material were observed. With a decrease of the overpotential to −0.1 V vs. RHE, an increase in the quantity of migrating platinum particles took place. At −0.2 V vs. RHE, a further rise in the particle migration was observed. The effect of the overpotential on the migration was explained by a higher hydrogen generation rate, the formation of a hydrogen monolayer on the platinum and the resulting changes of the platinum support distance. The mechanisms revealed in this study could describe a relevant source of degradation of PEM water electrolyzers.