Carbon-supported Pt–Sn/C bimetallic nanoparticle electrocatalystswere prepared by the simple reduction
of the metal precursors using ethylene glycol. The catalysts heat-treated under argon atmosphere to
improve alloying of platinum with tin. As-prepared Pt–Sn bimetallic nanoparticles exhibit a single-phase
fcc structure of Pt and heat-treatment leading to fcc Pt75Sn25 phase and hexagonal alloy structure of
the Pt50Sn50 phase. Transmission electron microscopy image of the as-prepared Pt–Sn/C catalyst reveals
a mean particle diameter of ca. 5.8nm with a relatively narrow size distribution and the particle size
increased to ca. 20nm when heat-treated at 500 ◦C due to agglomeration. The electrocatalytic activity
of oxygen reduction assessed using rotating ring disk electrode technique (hydrodynamic voltammetry)
indicated the order of electrocatalytic activity to be: Pt–Sn/C (as-prepared) > Pt–Sn/C (250 ◦C) > Pt–Sn/C
(500 ◦C) > Pt–Sn/C (600 ◦C) > Pt–Sn/C (800 ◦C). Kinetic analysis reveals that the oxygen reduction reaction
on Pt–Sn/C catalysts follows a four-electron process leading to water. Moreover, the Pt–Sn/C catalyst
exhibited much higher methanol tolerance during the oxygen reduction reaction than the Pt/C catalyst,
assessing that the present Pt–Sn/Cbimetallic catalystmay function as amethanol-tolerant cathode catalyst
in a direct methanol fuel cell