In-liquid plasma was generated in the carbon nanotube (CNT) dispersion fluid using platinum electrodes. The generated plasma spattered the surface of the platinum electrodes and dispersed platinum particles into the CNT dispersion. Therefore, the platinum nanoparticles were successfully formed on the CNT surface in the dispersion. The platinum nanoparticles were applied to the proton exchange membrane fuel cell (PEMFC) as a catalyst. The electrical power of 108 mW/cm(2) was observed from the fuel cell which was assembled with the platinum catalyst formed on the CNT by the in-liquid plasma method. (C) 2015 Elsevier B.V. All rights reserved.