Temperature dependent model of carbon supported platinum fuel cell catalyst degradation

The use of mathematical modelling for describing the degradation of platinum-based carbon-supported catalysts (Pt/C) in PEMFC plays a crucial role in the development of new materials and mitigation strategies as well as in the improved understanding of individual degradation mechanisms and their relation to the operational conditions. In this work we present the first physically based model of Pt/C catalyst degradation that fully covers the effects of temperature on detrimental electrochemical reactions, consequent platinum particles dissolution, detachment and agglomeration, and the resulting loss of electrochemical surface area. The model is verified on the results of six accelerated stress tests performed on an industrial benchmark catalyst at various temperatures and potential cycling windows. The model is capable of reproducing the results of all experiments using the same set of model parameters, compatible with DFT calculations for energy barriers of similar electrochemical reactions as well as with the parameters of existing degradation models, which confirms its plausibility. According to the model results, the dissolution and subsequent redeposition of platinum is strongly affected by the temperature and represents the main mechanism of particle growth at temperatures below 60 °C, with carbon corrosion induced detachment and agglomeration playing only a minor role in particle growth. • Temperature-dependent electrochemical model of Pt fuel cell catalyst is developed. • Catalyst electrochemical surface loss due to dissolution and agglomeration is modelled. • The model is tested on degradation experiments at various potentials and temperatures. • The credibility of the model is confirmed by good agreement with the experimental data. • Platinum dissolution and redeposition is recognised as the main degradation mechanism.