Phase-controlled solvothermal synthesis and characterization of nickel sulfides with good single crystalline nature

Dispersed rhombohedral NiS rods with high aspect ratios and rhombic dodecahedron-like cubic NiS2 crystals were prepared by solvothermal routes using NiCl2·6H2O and Na2S2O3·5H2O as reagents and ethylenediamine as a solvent, and 3D blossoming flower-like rhombohedral NiS microstructures were synthesized using different sulfur sources of thiourea. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersion spectrometry and selected area electronic diffraction. All the products were pure and had good single crystalline nature. The synthesis parameters were of great importance on the purity and morphology of the products. The possible growth mechanisms have been discussed based on the analyses of the effects of sulfur sources and solvent on the crystal structures and detailed configurations of the products. The present work is likely to help the phase-controlled synthesis of other metal chalcogenides.