Close packed polyacrylonitrile nanofibers containing platinum (11) acetylacetonate were fabricated by polymerization of acrylonitrile in a porous anodic aluminum oxide template. Subsequent pyrolysis results in carbon nanofibers wherein the Pt(II) salt is reduced in situ to elemental Pt. High-resolution transmission electron microscopy showed that the Pt nanoparticles are dispersed throughout the carbon nanofibers, have a size range of 1-4 nm, and are single crystals. Rotating disc electrode voltammetry suggests that the dispersion of Pt nanocrystals in the carbon nanofiber matrix should exhibit excellent electrocatalytic activity. (C) 2004 Elsevier B.V. All rights reserved.