Synthesis of flower- and rod-like nickel sulfide nanostructures by an organic-free hydrothermal process

Well-crystalline flower- and rod-like NiS nanostructures have been synthesized by an organic-free hydrothermal process at a low temperature of 200 °C. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were employed to characterize the as-synthesized NiS nanostructures. The effects of temperature and reaction time on the morphology have been also investigated. The two-step flake-cracking mechanism for the formation of flower- and rod-like NiS nanostructures was discussed. The products were also investigated by photoluminescence (PL) spectroscopy.