Revealing the Nanostructure of Mesoporous Fuel Cell Catalyst Supports for Durable, High-Power Performance

Achieving high power performance and durability with low Pt loadings are critical challenges for proton exchange membrane fuel cells. PtCo catalysts developed on new carbon black supports show promise by simultaneously providing good oxygen reduction kinetics local transport. We investigate the role of nanoscale morphology in these supported accessible (HSC-e HSC-f) conventional (Ketjen Black) porous carbons using 3D electron tomography, nitrogen sorption, electrochemical measurements. find that have hollow interiors mesopores larger more numerous than carbons. However, mesopore-sized openings (>2 nm width) too rare to account significant Instead we propose primary transport pathway into interior is through 1–2 microporous channels permeating carbon. The increased mesoporosity results a shorter diffusion pathlength constrictive, tortuous micropores support shell leading lower resistance. In testing, faster rates surface area loss, likely from fewer constrictive pores would mitigate coarsening, but maintain superior current density at end test improved