A novel synthetic route for the preparation of core shell like carbon-supported nanoparticles with a Pt-rich shell

Abstract

A novel synthetic process referred to as a protective coating method was developed for the fabrication of a carbon-supported Pt₂Ni₁ nanoparticle measuring approximately 5 nm in size with a Pt-rich shell via thermal treatment. A 3 to 5 nm thick polypyrrole layer encapsulating the surface of the Pt/C catalyst simultaneously acted as a sponge to absorb the Ni precursor and a physical barrier to inhibit the inevitable increase in particle size during the thermal treatment. The PPy layer does not behave as a poison to the catalyst because it is completely decomposed without carbonization on the Pt surface during the heat treatment in a H₂–Ar mixture. As a result, the resultant Pt₂Ni₁/C catalyst with a Pt-rich shell exhibited improved stability under acidic conditions and catalytic activity in an oxygen reduction reaction.