Electrodeposition of palladium-tin alloys from 1-ethyl-3-ethylimidazolium chloride-tetrafluoroborate ionic liquid was studied at 120 degrees C. Sn(II) chloride reacts spontaneously with Pd(II) chloride, producing Sn(IV) and Pd nanoparticles. Solutions containing Sn(IV) and Pd(II) were used for potentiostatic electrodeposition of Pd-Sn. The composition of the Pd-Sn electrodeposits varied with the solution composition and deposition potential. Different alloy phases were observed with X-ray diffraction measurements. Whereas the Pd-rich Pd-Sn solid solution deposits are composed of compact nodules, the Sn-rich intermetallic Pd-Sn deposits are composed of polyhedral crystals of various phases. Compared to Pd-coated electrodes, Pd-Sn solid-solution-coated electrodes show enhanced ethanol electro-oxidation efficiency and stability in alkaline aqueous solutions. As Sn content increased, new Pd/Sn intermetallic phases formed, resulting in reduced catalytic efficiency for ethanol oxidation. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3435322] All rights reserved.
