Synthesis of Pt3Sn Alloy Nanoparticles and Their Catalysis for Electro-Oxidation of CO and Methanol

Monodisperse Pt3Sn alloy nanoparticles (NPs) were synthesized by a controlled coreduction of Pt(II) acetylacetonate and Sn(II) acetylacetonate at 180-280 degrees C in 1-octadecene. In the synthesis, oleylamine was used as a reducing agent, and oleylamine/oleic acid served as surfactants. The sizes of the Pt3Sn NPs were tuned from 4 to 7 nm by controlling the metal salt injection temperatures from 180 to 240 degrees C. These mono-disperse Pt3Sn NPs were highly active for CO and methanol oxidation in 0.1 M HClO4 solutions, and therir activity and stability could be further improved by a postsynthesis thermal treatment of 400 degrees C in Ar + 5% H-2 for 1 h. They are promising as a practical catalyst for CO and methanol oxidation reactions in polymer electrolyte membrane fuel cell conditions.