Caillard, AmaelCharles, ChristineBoswell, RoderickBrault, Pascal2015-12-070957-4484http://hdl.handle.net/1885/17643A single plasma process involving three consecutive steps has been developed for producing high gas flow catalytic nanostructures on the electrodes of proton exchange membrane (PEM) fuel cells (FC). Using a high density helicon radio frequency (13.56 MHz) plasma, nickel is sputtered onto a porous carbon support. Changing the background gas from argon to methane/hydrogen allowed 2 μm long, 37 nm diameter carbon nanofibres (CNFs) to be grown by diffusion through the nickel clusters in a 'tip growth' mechanism at the relatively low temperature of 400°C. The third step involves plasma sputtering of platinum onto the CNFs, resulting in nanoclusters (3-8 nm) being formed on the periphery of the CNFs. Four FC cathodes were synthesized on carbon paper and PTFE/carbon loaded cloth (known as gas diffusion layer, GDL), both with and without CNFs, with the Pt/CNFs nanostructures grown on PTFE/carbon loaded cloth having the best FC performances. Compared with conventional FCs, the efficiency of sputtered platinum in the Pt/CNF based cathode is much higher than in a chemically deposited system over the entire range of operating current. This indicates that combination of different, simple, plasma techniques is an effective method for preparing highly efficient catalyst layers.Keywords: Carbon; Catalyst activity; Electrodes; Platinum; Porous materials; Proton exchange membrane fuel cells (PEMFC); Carbon loaded cloth; Carbon paper; Catalyst layers; Nanostructures; argon; carbon; nanofiber; nanomaterial; nickel; platinum; article; catalysi200710.1088/0957-4484/18/30/3056032015-12-07