Temperature dependency of the electrooxidation of Pt

The surface oxidation of platinum is an important process in the degradation of platinum electrocatalysts in polymer-exchange membrane fuel cells (PEMFCs). Upon growth and reduction of an ultrathin Pt oxide layer on the Pt catalyst surface, the surface morphology changes irreversibly and Pt dissolution occurs. In the past we performed comprehensive operando surface diffraction studies of the oxide formation and reduction on Pt(111) and Pt(100) and were able to provide an atomistic view of the oxide growth process. Up to now these fundamental studies have only been performed at room temperature. However, the operating temperature of PEMFCs is around 70°C and higher. In this experiment, we want to investigate the influence of the temperature on the oxide structure and oxide growth kinetics by operando high-energy X-ray diffraction (HESXRD). Thus, we want to provide further insight into the Pt surface processes under PEMFC-relevant conditions.