Accelerated stress tests for Pt/C electrocatalysts: An approach to understanding the degradation mechanisms

The degradation of the nanostructured platinum-based electrocatalysts during their operation poses a major problem for the performance and durability of PEMFCs and devices based on them. Therefore, the methodological aspects of research related to the quantitative assessment of the materials' degradation as well as the mechanism of the processes causing it are gaining increasing attention. The degradation processes of the same Pt/C catalyst containing the nanoparticles of similar size uniformly distributed over the surface of the carbon support were studied using eight relevant protocols of the accelerated stress testing. Special attention was paid to electron microscopy examination of the catalyst's microstructure before and after stress tests as well as to determination of the electrochemically active surface area and the activity of the catalyst in the ORR after the stress testing. We also studied the influence of the atmosphere, in which testing was performed, as well as the effect of the electrode rotation on the degradation rate. The results of the study carried out demonstrate the features of the catalyst's degradation in different modes and facilitate the choice of optimal protocols and stress testing conditions.