Particle Atomic Layer Deposition for Synthesis of Fuel Cell Catalytic Material

Fluidized bed Atomic Layer Deposition (ALD) is a scalable method for nanoscale catalyst design, and has potential to address many of the persistent material challenges associated with PEM fuel cells, namely utilization and durability of the platinum catalyst. ALD was carried out to deposit platinum nanoparticles on functionalized and unmodified carbon black with both combustion and hydrogenation chemistries. Reactions throughout the ALD cycle were monitored using mass spectrometry and IR spectroscopy to clarify the deposition chemistry. The synthesized materials were evaluated in hydrogen pumping tests and as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cell experiments. Hydrogenation made finer, more dispersed Pt nanoparticles that performed similarly to their commercial equivalent when pumping hydrogen; oxygenation made a coarser catalyst that underperformed commercial Pt/C. The hydrogenation catalysts deposited on functionalized carbon were found to be ineffective in ORR testing due to poor water management in the fuel cell, which was attributed to reduced hydrophobicity within the catalyst layer.