In this study, firstly, polyethylenedioxythiophene (PEDOT)/carbon (C) composite material was synthesized by oxidative chemical polymerization. Then, PEDOT/C supported platinum (Pt) nanoparticles were prepared by using supercritical carbon dioxide (scCO(2)) deposition method. The prepared composite and catalyst were characterized by using BET, TGA, XRD and TEM techniques. The Pt loading over the support was achieved as 10%. TEM results showed that highly dispersed and small nanoparticles over the composite material can be obtained by using scCO(2) deposition method. (C) 2014 Elsevier B.V. All rights reserved.