Synthesis and electrocatalytic oxygen reduction properties of truncated octahedral Pt3Ni nanoparticles

Abstract

Pt3Ni nanoparticles have been obtained by shape-controlled synthesis and employed as oxygen reduction electrocatalysts for proton exchange membrane fuel cells (PEMFC). The effects of varying the synthesis parameters such as the types of the capping agent and the reducing agent, and the reaction time have been systematically studied. The as-prepared Pt3Ni nanoparticles were subjected to a butylamine-based surface treatment in order to prepare carbon-supported electrocatalysts. The Pt3Ni electrocatalysts show an areaspecific activity of 0.76 mA/cm2(Pt) at 0.9 V in an alkaline electrolyte, which is 4.5 times that of a commercial Pt/C catalyst (0.17 mA/cm2 (Pt)). The mass activity reached 0.30 A/mg(Pt) at 0.9 V, which is about twice that of the commercial Pt/C catalyst. Our results also show that the area-specific activities of these carbon-supported Pt3Ni electrocatalysts depend strongly on the (111) surface fraction, which is consistent with the results of a study based on Pt3Ni extended single-crystal surfaces. © 2011 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.