Carbon-Supported Pt−Co Catalysts Prepared by a Modified Polyol Process as Cathodes for PEM Fuel Cells

Abstract

In this work, carbon-supported Pt 70 Co 30 nanoparticles were prepared by a polyol process using a long-chain diol as reducer (hexadecanediol) and oleic acid and oleylamine as stabilizers. Depending on the synthesis conditions, Pt 70 Co 30 /C nanocatalysts with very small particle size (1.9 ± 0.2 nm) and narrow distribution homogeneously dispersed on the carbon support and having a high degree of alloying without the need of thermal treatments were obtained. The as-prepared catalyst presents an excellent performance as proton exchange membrane fuel cells (PEMFC) cathode material. In terms of mass activity (MA), the Pt 70 Co 30 /C electrocatalysts produced single fuel cell polarization response superior to that of commercial catalyst. To analyze alloying effects, the result of thermal treatment at low temperatures (200−400 °C) was also evaluated and an increase of average crystallite size and a lower degree of alloying, probably associated to cobalt oxidation, were evidenced.