Synthesis of single-crystalline lanthanum hexaboride nanocubes by a low temperature molten salt method

Abstract

A low temperature molten salt method was developed to prepare lanthanum hexaboride (LaB6) nanocubes. Lanthanum trichloride (LaCl3) and sodium borohydride (NaBH4) were chosen as lanthanum and boron source respectively. A eutectic LiCl/KCl mixture was used as the molten salt medium. Single-crystalline LaB6 nanocubes with a mean size of 94.7 nm were successfully synthesized by the molten salt method at 800 °C. X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectrophotometer (Raman) were used to characterize the composition, morphology and microstructure of the samples. To make clear of the role of molten salt medium in synthesis of LaB6 nanocubes, a direct solid-state reaction of LaCl3 and NaBH4 was also conducted under the same reaction conditions.