Suppression of Pt Nanocluster Aggregation and Enhanced Oxygen Reduction Activity by Heteroatom Doping of Carbon Nanotubes

Abstract

Increasing the performance of platinum (Pt) catalysts for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells could reduce the amount of this expensive metal that is required. Pt nanoclusters (NCs) can provide substantially increased ORR activity per unit mass of Pt and so are of interest. However, there has been no research regarding supports for Pt NCs exhibiting both high specific surface area and high conductivity. The present work improved the ORR activity and durability of carbon nanotubes by doping with nitrogen or sulfur to reduce the level of aggregation of supported Pt NCs. Pt NCs supported on sulfur-doped carbon nanotubes showed 2.32 times higher activity (425.2 A/g Pt ) and greater durability compared with those of commercially supported Pt nanoparticle catalysts.