Sodium Vapor-Induced Synthesis of Intermetallic Pt₅Ce Compound Nanoparticles

We have developed a synthetic route that uses sodium for the production of intermetallic Pt₅Ce nanoparticles (ca. 6 nm average diameter) supported on carbon powder. Sodium melt was demonstrated to reduce a powder mixture of PtCl₂ and CeCl₃ to form submicrometer Pt₅Ce particles with the simultaneous formation of NaCl. The NaCl-CeCl₃ melt mixture and Na melt were formed during heating, which led to a uniform reaction between Pt and Ce, and the melt induced grain growth. The synthetic procedures were then modified to supply sodium vapor to the vicinity of the metal sources supported on carbon powder with an aim to suppress grain growth. Pt₅Ce nanoparticles were successfully formed on the carbon support with high loading and dispersity.