Pt3Y electrocatalyst for oxygen reduction reaction in proton exchange membrane fuel cells

Abstract

We report here that significant electrocatalysis occurs during oxygen reduction reaction (ORR) at the Pt3Y alloy thin film electrodes. In addition, we synthesized Pt3Y alloy nanocatalysts for use in proton exchange membrane fuel cells, fabricated by using a high pressure sputtering technique in a gaseous mixture of Ar and He. Rather than the dense film deposited by conventional sputtering techniques, the resulting structure was comprised of a Pt3 Y alloy nanocatalyst layer with an average particle size of 10–12 nm. The Pt3Y alloy nanocatalysts were characterized by scanning electron microscopy, transmission electron microscopy, high-resolution X-ray photoelectron spectroscopy, and X-ray absorption near edge spectroscopy. The cell performance of the membrane electrode assembly with multiple layers of sputter-deposited Pt3Y alloy nanoparticles and spray-deposited Nafion–carbon-ink improved dramatically compared to that obtained with the Pt only nanoparticles. The high performance of Pt3Y alloy nanocatalysts fabricated at a sputtering pressure of 200 mTorr (Ar/He = 1) was due to miniaturization of the Pt3Y alloy particles, formation of the porous catalyst layer, and enhancement of the kinetic activity for ORR.