Fabrication of Carbonized Block Copolymer Particles for Cathode Catalyst of Proton Exchange Membrane Fuel Cell

A porous carbon particle attracted great attention as supporting material for electrocatalyst due to its high conductivity and large surface area. Herein, we demonstrate a robust strategy to carbonize block copolymer (BCP) particles with maintained their size and morphology using etchable BCP (i.e., polystyrene-block-polydimethylsiloxane (PS-b-PDMS)). Key of generating porous carbon material is to introduce cross-linking, which can enhance the thermal stability of linear BCP during carbonization. We produced monodisperse cylinder-forming BCP particles using membrane emulsification, followed by cross-linking and carbonization. We confirmed that its morphology and size distribution is well maintained after carbonization. Moreover, we demonstrate carbonized BCP (cBCP) particles as a supporting material of electrocatalyst with depositing low amount (1 wt%) of platinum (Pt) catalyst on the cBCP particles (Pt@cBCP). Pt@cBCP showed 3.6 times-higher mass activity than commercial Pt/C catalyst in oxygen reduction reaction (ORR). Moreover, we confirmed the advantages of the porous structure by comparing them with a nonporous carbon sphere.