Degradation kinetics of Pt during high-temperature PEM fuel cell operation Part III: Voltage-dependent Pt degradation rate in single-cell experiments

Degradation of the Pt catalyst is one of the most serious problems related to the high-temperature fuel cell with a proton-exchange membrane (HT PEM FC). Despite many publications on this topic, no clear relationship between Pt nanoparticle growth and HT PEM FC operating conditions has been formulated yet. The goal of the presented study is to determine the dependence of Pt nanoparticle growth on the operational voltage of the HT PEM FC by means of experimental single-cell testing with subsequent post mortem analysis of the catalyst layers on the two electrodes. Well-defined, long-term tests performed at constant voltage in combination with several post mortem instrumental methods enabled the prediction of the development of Pt nanoparticle distribution. At higher voltages, Pt nanoparticle growth was less pronounced than at low voltages. This was likely caused by the change in the rate-limiting step in Pt nanoparticle growth. (C) 2020 Elsevier Ltd. All rights reserved.