The cost, performances and lifespan of a cell proton exchange membrane (PEM) are currently limited by the electrochemical reactions at the cathode. In collaboraton with Liten [Nicolas Pauc from our laboratory, Arnaud Morin et Samuele Galbiati, CEA-LITEN], we therefore seek to strengthen the action of the catalyst (platinum) by leveraging its apparent surface and taking advantage of the excellent electrical conductivity of platinum to remove carbon from electrodes. For this, they have designed and built a "nanostructure" allowing both to catalyze reactions and to reap the resulting current.

We managed to produce aligned platinum nanotubes by chemical vapor deposition on a porous alumina substrate. We then hot pressed the whole thing on the polymer membrane of the cell, dissolved completely alumina and finally redeposited a thin layer of protons conducting polymer. The platinum nanostructure proves more effective than platinum coated carbon electrode with a gain close to 30% for the current produced for a given surface area of platinum.

It remains to optimize the geometry and density of the nanotubes. Another manufacturing process more efficient platinum, metal evaporation, should also be evaluated. The use of platinum alloys and nanostructures such as "core-shell" should also be explored to further reduce the total weight of platinum per stack.