The solution plasma process (SPP) was employed to synthesize a Pt/C catalyst for proton exchange membrane fuel cell (PEMFC) applications. The Pt nanoparticles (Pt NPs) were produced by reducing the H 2 PtCl 6 ·6H 2 O, and the carbon supports were formed simultaneously by the erosion of the carbon electrode during the SPP. In order to obtain the optimal conditions for the high electrocatalytic activity of the Pt NPs, the morphology change of the Pt NPs with various cetyl trimethylammonium bromide (CTAB) concentrations was examined. The Pt NPs synthesized without CTAB formed large particles about 38.14nm in diameter, consisting of many primary particles of about 1.85nm in diameter. The Pt NPs synthesized with CTAB were well-dispersed with an average size of 1.90nm in diameter. The electrocatalytic activities of the Pt/C catalysts were evaluated using cyclic voltammetry (CV), and the results indicated that the Pt/C catalyst without CTAB showed more than twice the activity with respect to the hydrogen oxidation reaction than the Pt/C catalyst with CTAB, suggesting that the morphology and surface property of the Pt/C strongly affected the electrocatalytic activity. The Pt/C catalyst synthesized via the SPP is a promising candidate as a PEMFC catalyst.