High Performance PEM Fuel Cell with Low Platinum Loading at the Cathode Using Magnetron Sputter Deposition

Platinum cluster formations have been investigated as a way to reduce the amount of Pt at the cathode of polymer electrolyte membrane fuel cells. One, two, and three layers of Pt (0.05？mg/cm2) sputtered directly on microporous layers of gas diffusion layers with and without interfacial carbon-Nafion layers and carbon-polytetrafluoroethylene (CPTFE) layers have been used as a cathode. Comparison with experimental results had showed that the best performance was obtained with three layers of Pt sputtered on carbon-Nafion containing 34.8？wt.% of Nafion and sputtered carbon-polytetrafluoroethylene containing 16.9 wt.% of polytetrafluoroethylene. High limiting current densities (>1.1？A/cm2) have been reached with cathode Pt loading as low as 0.05？mg/cm2. SEM imagery and cyclic voltammetry characterization have been performed to consolidate this study. High Pt utilization can be showed by this method. The factor influencing Pt utilisation in the oxygen reduction reaction is intrinsically related to Pt clusters formation and helps in enhancing the PEMFC performance with low Pt loading. 1. Introduction Several researches have been done in the latest decade to reduce the amount of Pt in polymer electrolyte membrane fuel cells (PEMFCs) principally in the cathode to reduce its weight, volume, and cost [1–8]. The oxygen reduction reaction (ORR) occurring at the cathode of a PEMFC cell is catalyzed by high loadings of Pt to reduce significantly the overpotential loss. The activation overpotential is the principal loss, and its magnitude depends on the reaction kinetic parameters. More precisely, it depends on the size of the exchange current density [9]. Therefore, improving reaction kinetic performance is done by increasing the exchange current density, which depends on reactant concentration, activation barrier, reaction sites, and temperature. Those factors hinder large-scale commercialization and have motivated intense research to low loading of Pt, more active, inexpensive, and stable. Promising directions include metal alloys, notably Pt- and Pd-based inorganic compounds such as chalcogenides and organic compounds such as transition metal macro-cycles, have been investigated [10–13]. In addition of, the complexity of the catalyst layer has permitted the studies about coating methods, water management, Nafion content, and carbon supported Pt [6, 14–19]. It is obvious that the approach of Pt alloying with nonnoble transition metals can create some active alloy catalysts for catalytic activity enhancement towards ORR [12]. However, there are many concerns about