Eutectic salt mixture-assisted sodium-vapor-induced synthesis of Pt-Ca nanoparticles, and their microstructural and electrocatalytic properties.

We have fabricated Pt-Ca nanoparticles with oxygen reduction reaction catalytic activity via a sodium vapor-induced synthesis method. Prior addition of NaCl to form a eutectic mixture of CaCl2 and NaCl facilitated the formation of intermetallic Pt2Ca nanoparticles. Pt3Mg and Pt5Sr nanoparticles also were suggested to be producible.

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.

Chemical solution deposition of the highly c-axis oriented apatite type lanthanum silicate thin films.

Highly c-axis oriented apatite-type lanthanum silicate (LSO) thin films were fabricated by a simple solution coating method. In the solution coating method, LSO thin films are obtained by crystallization of initially deposited amorphous LSO precursor thin films. The degree of orientation was influenced by the precursor morphologies and a dense LSO precursor led to a high c-axis orientation perpendicular to the substrate. The oriented LSO thin films were composed of columnar grains with a single crystal orientation over the entire film thickness. In-plane orientation was not detected, which indicates that the c-axis orientation of the LSO thin films can be attributed to self-orientation.