Pt/Nafion membranes with different Pt loading were obtained by a permeation-reduction method. With the aid of SEM and XRD, the Pt disposition process inside the membrane as well as on the surface of Nafion during different period is studied. Based on the experimental results and analysis, it was found that the Pt disposition process could occur, both on the surface of and inside the membrane, although it took place mainly in an interior region of the membrane near the surface. It is beneficial to the growth of Pt(111) crystal facet using KBH~4 to reduce H~2PtCl~6. According to SEM photographs of Pt/Nafion during different reaction stages, the mechanisms of the Pt growth on the membrane surface and inside the membrane are proposed.

Key words: ION EXCHANGE FILM, PLATINUM, GROWTH, SEDIMENTATION, MECHANISM, X-RAY DIFFRACTION ANALYSIS, SCANNING ELECTRON MICROSCOPES