Low temperature synthesis of LaB6 nanoparticles by a molten salt route

- LaB6 nanoparticles with high purity were successfully synthesized by a novel molten salt route.
- Temperature of the molten salt route was nearly 600 °C lower than those required by the direct solid-state reaction method.
- Morphology and size of LaB6 nanoparticles changed with increasing temperature.
- The molten salt synthesis process of LaB6 nanoparticles was dominated by the “dissolution/precipitation” mechanism.

Lanthanum hexaboride (LaB6) nanoparticles were successfully synthesized via the reaction of lanthanum trichloride (LaCl3) and sodium borohydride (NaBH4) in a molten KCl/LiCl eutectic salt. The changes in the phase composition and morphology of LaB6 as a function of temperature were systemically investigated. By increasing the temperature from 600 °C to 800 °C, the crystallinity of LaB6 particles increased and the sphere-like morphology of 49.0 nm changed to the cubic shape of 94.7 nm. Additionally, the microstructure and chemical composition of LaB6 nanocubes were further characterized, and the possible synthesis mechanism of LaB6 nanoparticles was proposed based on the experimental results.

LaB6 nanoparticles with high purity were successfully synthesized by a molten salt route using LaCl3, NaBH4 and KCl/LiCl eutectic salt as raw materials at 600-800 °C. These synthesis temperatures are nearly 600 °C lower than those required by the conventional direct solid-state reaction method. LaB6 nanoparticles with a sphere shape of 49.0 nm and a cubic shape of 94.7 nm were obtained at 600 °C and 800 °C, respectively. The molten salt synthesis process of LaB6 nanoparticles was dominated by the “dissolution/precipitation” mechanism.122