Carbon supported catalyst Pt-Sn/C was synthesized in reverse micelle solution of water/AOT/ cyclohexane [AOT: bis-(2-ethylhexyl)sodium sulfosuccinate, (aerosol-OT)] and characterized by TEM, XRD, XPS and cyclic voltammetry (CV) techniques. TEM results showed that the Pt-Sn bimetallic particles were well dispersed on the carbon support with narrow size distribution and regular spherical shape. The average size of the particles prepared is about 2.7 nm, and the particle size was increased with the increase of ω value (water-surfactant molar ratio). XRD results show that Pt has fcc crystalline structure and did not alloyed with Sn. XPS results showed that the surface of the catalyst prepared was mainly covered by metallic platinum, Sn(II) and/or Sn(IV) species. CV results show that the methanol electrooxidation activity was decreased with the increase of ω value, and the catalyst prepared has lower peak current potential and higher I_f/I_b [the ratio of the forward anodic peak current density (I_f) to the backward anodic peak current density (I_b) obtained from CV] than commercial catalyst of Pt-Ru/Vulcan XC-72 (20 wt% Pt-Ru, E-TEK company).

Key words: reverse micelle method, catalyst, Pt-Sn/C, direct methanol fuel cell, methanol electrooxidation