Polymer-derived carbon based low-platinum content catalyst for the oxygen reduction reaction in polymer electrolyte membrane fuel cells

Abstract

Carbon-based catalysts for the fuel cell application have long been established as the most practical supporting materials due to their cost and conductivity. The commercially available Platinum on carbon (Pt/C) uses simple smooth-surface carbon with platinum nanoparticles (NPs) deposited on the surface. While Pt/C is cost-effective and has been shown to exhibit high power performance, its biggest limitation lies in the poor durability and high Pt usage. Our group synthesized graphitized polystyrene-based carbon (gPS) by carbonization at various temperature with an iron precursor as an alternative to the conventional smooth-surface carbon with comparable cell performance capabilities and superior durability. The MEA mass activity of the catalyst was 0.74 A/mgPt, which easily surpasses the commercial Pt/C by twofold. When comparing their durability, at 0.6V, gPS catalyst retained 72% of its performance while the Pt/C retained 60%. Interestingly, through the Raman analysis, with increasing carbonization temperature of polystyrene, defective carbon feature of the catalyst increased relative to the graphitic features. The MEA performance seemed to increase consistently with increasing carbonization temperature due to the higher distribution mesopores, and the higher kinetic activity compared to commercial Pt/C is likely attributed to the effects of improved dispersion from 3-5 nm carbon meso/micropores allowing strong anchoring between the carbon and the Pt alloy NP.