Effect of the Preparation Method on the Electrocatalytic Activity of Pt-Sn/Nanotubes Catalysts Used in DMFC

Abstract

A series of bimetallic Pt-Sn catalysts supported on multiwalled carbon nanotubes (NT) for methanol oxidation reaction was prepared by different methods that involve ethylene glycol synthesis under reflux conditions and sodium borohydride reduction (using water or ethylene glycol as solvents) at 55°C. Pt-Sn/NT catalysts containing 20 wt% platinum with Pt:Sn atomic ratios of 5:1, 3:1 and 1:1 were prepared and their morphology and electrocatalytic activities were characterized by temperature programmed reduction, X-ray photoelectron spectroscopy, H2 chemisorption, benzene hydrogenation reaction, transmission electron microscopy, cyclic voltammetry, linear sweep voltammetry, chronoamperometry and CO stripping. The electrocatalysts performance depends strongly on the preparation method and Pt:Sn atomic ratios, with the Pt3Sn1/NT sample prepared by ethylene glycol displaying the highest activity for methanol electrooxidation, a good CO tolerance and an important stability.