Ethanol Electrooxidation on Pt-Sn Catalysts Deposited by Pulsed Laser Ablation

Abstract

Pt3Sn catalysts were prepared from pure Pt and Sn targets by crossed beam pulsed laser deposition. The deposition was performed either under vacuum or in the presence of a He background pressure (1, 2, 3, 4 and 5 Torr). The pressure in the deposition chamber influences the surface structure and the morphology of the catalytic nanoparticles, as determined from scanning electron microscopy. Cyclic voltammogram curves reveal that Pt3Sn catalysts deposited under He lower the onset oxidation potential of ethanol compared to Pt3Sn electrodes synthesized under vacuum. This effect is particularly evident for Pt3Sn elaborated at 2 Torr He which provides a high current density value close to 20 mA.cm-2 at 0.7 V vs. RHE. Chronoamperometric measurements conducted at + 0.5 V vs. RHE also demonstrated that Pt3Sn deposited at 2 Torr He is the most active electrocatalyst after 1 hour of electrolysis.