This book focuses on the fundamentals of the plasma modification techniques, polymer electrolyte membrane fuel cells, and how plasma techniques can be utilized to improve the efficiency of the fuel cells. Platinum/Carbon is used as a catalyst for fuel cells and the objective of this study is to modify the carbon support to improve the catalytic efficiency of fuel cell electrocatalysts. A radio-frequency tumbling plasma reactor is used to modify the carbon support to have uniform coating on the carbon nanoparticles without affecting its bulk properties. Nitrogen and allylamine plasmas are used to obtain nitrogen containing functional groups including amine moieties. The nitrogen containing functional groups are found to have a high affinity for binding platinum and good dispersion of platinum nanoparticles on the treated carbon surface. This book provides good information on the catalyst synthesis of fuel cells and the characterization of the catalysts using different analytical and electrochemical techniques which should be useful for professionals in the field of electrochemistry, energy devices and catalysis.