Improving High-current-density Performance of PEMFC through Much Enhanced Utilization of Platinum Electrocatalysts on Carbon.

We report an effective approach to the synthesis of high-content and high-dispersion Pt nanoparticles (NPs) on XC-72 carbon black as cathode electrocatalyst with improved high-current-density performance in proton exchange membrane fuel cells (PEMFCs). While exceptionally high catalytic activity for oxygen reduction reaction (ORR) was reported based on rotating disk electrode (RDE) technique, such catalysts do not deliver at nearly the same level performance in PEMFC due to the lack of optimized design of catalyst structures on carbon support. We recently developed a synergistic synthesis method to make ex-ceptionally high-content and finely dispersed Pt catalysts, which showed the highest Pt-electroactive surface area and the high-est Pt mass activity for ORR among the electrocatalysts tested. More importantly, the membrane electrode assembly (MEA) made with this catalyst had a superb performance at the current density higher than 1200 mA cm-2 in a hydrogen-air PEMFC measurement. 195Pt NMR was used to analyze the molecular structures of the metal precursors and to understand the mecha-nisms for the formation of Pt catalysts at high dispersity and uniformity.