Nanocat, development of advanced catalysts for PEMFC Automotive Application
Résumé
Today, extend life time of low loaded MEA is a key challenge for the widespread of the technology. One of cause of the decrease of performances of MEA is the loss of electrochemical surface area, which can be due Pt dissolution, Pt coarsening and support corrosion. To tackle that issue, NanoCAT partners developed Pt free catalyst for both anode and cathode side, they also developed new resistant support to limit the loss of ECSA. The use of resistant support toward corrosion is a promising route to increase the life of MEA active layers. NanoCAT is studying the use of carbon nanotube (CNT) and doped metal oxide (MOx) as catalysts support. Deposition of catalyst (Pt and Pt alloy) has been made by both PVD and wet chemistry. PVD allow to prepare ultra low loading electrode (30 μgPt/cm2). Specific modifications of the CNT have been developed to facilitate the Pt deposition and enhance the particles dispersion on it. Preparation route of MOx have been tuned to obtain acceptable electron conductivity (0.95 S/cm) and porosity (pores size distribution: 20-50 nm, SBET: 90 m2/g). Pt on modified CNT shows similar performance as commercial Pt/C catalyst but lower loss of ECSA by performing accelerated stress test on rotating disk electrode. Degradation study showed that loss of ECSA occurs at the cathode as well as the anode in the specific conditions of the project. According to that, the project catalysts have been integrated at the anode and the cathode of MEA.