Highly branched Pt Cu nanodandelion with high activity for oxygen reduction reaction

Abstract A facile hydrothermal route has been developed to synthesize the highly branched Pt 58 Cu 42 nanoparticles via mixing the H 2 PtCl 6 and CuCl 2 with octadecylamine. The Pt 58 Cu 42 after post treatment forms a dandelion flower 3-D structure. A combination of both the branched shape and Pt Cu composition effects in the Pt 58 Cu 42 -nanoparticles shows superior electrocatalytic activity and durability to commercial Pt black for oxygen reduction reaction. The mechanism for the de-alloying and reconstructing of the Pt 58 Cu 42 -nanoparticles in electrochemical activity and durability tests has been proposed. It is found that after the durability process, the Pt 58 Cu 42 precursor alloy changes into a substantially Pt enriched Pt Cu alloy (Pt 79 Cu 21 ) with a Pt skin. The Pt skin effectively prevents the further dissolution of the Cu below the near-surface to enhance its durability. What's more, the Pt skin exposed to (111) planes which have the lowest surface energy among the low-index planes further promotes the improvement of durability of the Pt Cu catalyst.