Structure-to-Property Relationships in Non-Platinum Group Fuel Cell Catalysts: Examination of Length Scale Correlations

Abstract

Hydrogen fuel cells provide a means for direct electrical generation without the need for a mechanical-work intermediate. They are efficient and produce only water as a product Fuel cells require catalysis to oxidize hydrogen and reduce oxygen at the anode and cathode, respectively. Current fuel cells rely on platinum as a catalyst, which is expensive and is a fundamentally limited resource Catalyst performance is not dependent simply on chemical species or total surface area. There is a complex interplay between concentrations of different chemical moieties and morphology on different length scales. While the fact that the chemistry plays a crucial role seems self-evident, the roles of morphology are less straight-forward. Pore size and surface roughness length scales determine the efficiency and types of diffusion that allow fuel to be delivered to the catalyst surface and for removal of products This presentation focuses on elucidation of catalyst morphology on different length scales. Surface morphology is explored using digital image processing (DIP) of SEM and AFM images. Previous DIP work has used high and low pass filtering to separate images by length scales Refinement of filtering techniques has yielded specific correlations between morphology and macroscopic properties across a range of Fe-N-C catalysts. The sample set shown in Acknowledgment