Three-dimensional PtNi hollow nanochains as an enhanced electrocatalyst for the oxygen reduction reaction
Three-dimensional porous PtNi hollow nanochains were successfully synthesized via a galvanic replacement method using Ni nanosponges as sacrificial templates in an aqueous solution. It is found that the composition and shell thickness of 3D PtNi hollow nanochains can be easily controlled by tuning the concentration of Pt precursors. The as-prepared PtNi hollow nanochains with an optimized composition present a high electrochemical surface area (70.8 m2 g−1), which is close to that of commercial Pt/C (83 m2 g−1). Moreover, the PtNi catalyst with a Pt content of ∼77% presents superior electrocatalytic performance for the oxygen reduction reaction compared to commercial Pt/C. It shows a mass activity of 0.58 A mgPt−1, which is around 3 times higher than that of Pt/C. This strategy may be extended to the preparation of other multimetallic nanocrystals with 3D hollow nanostructures, which are expected to present high catalytic properties.