Manipulating agglomerate morphology in catalyst slurries: Insights into the synergistic effect of multiple parameters

It is well-established that the composition of catalyst slurry significantly impacts the formation of the catalyst layer in proton exchange membrane fuel cells (PEMFCs), particularly concerning the morphology and size of agglomerates. These aspects play a crucial role in determining the structure of the three-phase interface and the number of effective catalyst sites. This study explores the influence of various parameters and solvents used during slurry preparation on the size and morphology of agglomerate particles. Our research results indicate that the particle size in the slurry can be reduced to 212.8 nm, through high pressure, prolonged duration, and lower temperature, while higher temperatures will lower the surface potential of particles, causing to re-aggregate. Changes in pH and Zeta potential reflect variations in ionomer solvation during the aggregation of the slurry. Augmenting water content contracts ionomer agglomerate morphology, enhancing surface particle morphology on the catalyst layer, promoting pore formation, ameliorating drainage capacity (particularly under high current density), increase the polarization voltage and power density to 0.632V@2A cm−2 and 1.26W @ 2A cm−2.