Simple Synthesis of Urchin-like Pt-Ni Bimetallic Nanostructures for Oxygen Reduction Reaction Electrocatalyst Application

Abstract

Proton exchange membrane fuel cells (PEMFCs) are considered as one of the most promising environmentally friendly energy technologies to produce electricity. In PEMFCs, the most important reaction is oxygen reduction reaction (ORR) at cathode. Pt metal is widely used as electrocatalyst for ORR in commercial fuel cells. However, its practical use is limited by high cost because Pt is an element hardly found on the Earth crust. A high-activity electrocatalyst accelerating the ORR reaction must be developed to commercialize PEMFCs as ORR is the bottleneck in the overall reactions. Among many ORR electrocatalysts reported so far, Pt-Ni alloy is known as a promising candidate for high-activity catalyst materials because of its low cost and enhanced activity compared to Pt. Various nanostructures of the Pt-Ni alloy materials have been tested as ORR electrocatalysts to increase the surface to volume ratio and to enhance catalytic performance. Herein we synthesized urchin-like Pt-Ni bimetallic nanostructures by a simple heat-up method. Alloy composition was adjusted by varying the molar ratio of precursors. These urchin-like Pt-Ni bimetallic nanostructures showed higher catalytic activity in ORR than the commercial Pt catalyst.