Preparation, characterization and degradation mechanisms of PtCu alloy nanoparticles for automotive fuel cells

► PtCu core–shell advancement for automotive PEMFCs. ► Stability of copper platinum catalysts. ► Basic data for catalysts composition formulation for fuel cells. ► Degradation fingerprint for evaluation of catalysts. ► Startup/shutdown high potentials limit the catalysts stability. Electrochemically dealloyed PtCu alloy nanoparticles successfully meet the automotive technology target of having four times higher Pt mass activity for the electroreduction of molecular oxygen compared to current state-of-the-art platinum catalysts [1]. However, the catalysts must also maintain their activity throughout the aggressive automotive drive-cycles in order to be implemented in fuel cells cars. Here, the durability of dealloyed PtCu catalysts was systematically evaluated under various voltage-cycles using a rotating ring disk electrode. The stability of the non-noble metal alloy component was proven at electrode potentials below 0.6V. The platinum stability was evaluated at potentials up to 1.1V to avoid carbon corrosion and then up to 1.2V to be closer to the more aggressive cycles developed in startup/shutdown events of the fuel cells. The major known failure modes such as non-noble metal dissolution, platinum dissolution, and particle growth/agglomeration were monitored in order to understand closely the PtCu nanoparticles behavior under different potential cycles and to provide a degradation fingerprint.