Performance of proton exchange membrane fuel cell electrodes prepared by direct deposition of ultrathin platinum on the membrane surface

Proton exchange membrane fuel cell (PEMFC) electrodes were fabricated using a plasma-sputtering technique that deposits platinum directly on the surface of the Nafion electrolyte. This thin catalyst layer showed remarkable improvement in utilization efficiency, defined as the utilizable portion of the total deposited catalyst. This efficiency, equivalent to 0.043 mg Pt cm(-2) loading of platinum, is about ten times higher than that of the electrodes produced by conventional methods. Application of carbon/Nafion ink on the bare Nafion surface prior to the initial sputtering, and repetition of the sputtering followed by the application of the ink on the treated surface after each sputtering, greatly enhanced the utilization efficiency of the loaded platinum. (C) 1999 The Electrochemical Society. S0013-4651(99)03-083-9. All rights reserved.