FePt nanoparticles assembled on graphene as enhanced catalyst for oxygen reduction reaction.

Seven-nanometer FePt nanoparticles (NPs) were synthesized and assembled on graphene (G) by a solution-phase self-assembly method. These G/FePt NPs were a more active and durable catalyst for oxygen reduction reaction (ORR) in 0.1 M HClO(4) than the same NPs or commercial Pt NPs deposited on conventional carbon support. The G/FePt NPs annealed at 100 °C for 1 h under Ar + 5% H(2) exhibited specific ORR activities of 1.6 mA/cm(2) at 0.512 V and 0.616 mA/cm(2) at 0.557 V (vs Ag/AgCl). As a comparison, the commercial Pt NPs (2-3 nm) had specific activities of 0.271 and 0.07 mA/cm(2) at the same potentials. The G/FePt NPs were also much more stable in the ORR condition and showed nearly no activity change after 10 000 potential sweeps. The work demonstrates that G is indeed a promising support to improve NP activity and durability for practical catalytic applications.