Role of catalyst layer composition in the degradation of low platinum-loaded proton exchange membrane fuel cell cathodes: An experimental analysis

This study investigates the impact of catalyst layer (CL) composition on the performance and durability of proton exchange membrane fuel cells (PEMFCs). Membrane electrode assemblies (MEAs) are manufactured using six different cathode CLs (CCLs) by varying the platinum (Pt)-loading, Pt-to-carbon weight percentages (Pt/C wt.%), mass fraction of bare carbon particles, carbon support material, and CL thicknesses. Each MEA is subjected to comprehensive electrochemical characterization procedures followed by one of the two different accelerated stress tests (ASTs) to analyze the impacts of Pt-dissolution and carbon corrosion degradation mechanisms separately. Experimental results show that the Pt/C wt.% and CL thickness have a dominant role in the rate of Pt- dissolution. While the addition of bare carbon particles decreases the rate of Pt-dissolution degradation, lower Pt/C wt.% causes higher performance loss. The carbon corrosion degradation is more pronounced in high Pt- loaded CLs since Pt particles catalyze the carbon oxidation reaction, whereas for constant Pt-loaded CLs, higher Pt utilization leads to increased degradation and CCL thinning, as observed through post-mortem scanning electron microscopy (SEM). No significant relation is found between the carbon corrosion rate and the CL thickness.