Molecular Dynamics Simulations of Plasma Sputtered Ultra-low Platinum Nanocatalyst Growth
Résumé
Magnetron sputtering deposition has already demonstrated its ability for the fabrication of efficient PEMFC
electrodes with high Pt utilization rate.
As the nanoparticle growth by sputtering methods is atomic by nature, simulations at the molecular level are
expected to be relevant for understanding basic mechanisms of this deposition method. Indeed, molecular
dynamics (MD) as being able to exactly calculating the trajectory of atomic systems is a suitable method for
addressing this topic, especially in the context of plasma sputtering. Very recently, it has been shown that
MD simulations allowed confirming and predicting the morphology and structure of Pt nanocatalysts.
As bimetallic Pt alloys can improve the activity and stability of PEMFC’s catalysts, MD simulations on PtxX (X
being a less noble or common metal) deposition and growth are carried out for studying the preferred
morphology and structure (size, geometry, atomic arrangements…) of such clusters. Both formation methods,
i.e. on the surface or during time of flight to substrate, is also addressed for understanding the best growth
mode for catalyst coated backing or membrane. Radial distribution functions and X-Ray Diffraction pattern are
systematically computed for enabling direct comparison with experiments.