Solvothermal synthesis and characterization of cobalt sulfide nanocrystals

The CoS nanocrystals were synthesized by a solvethermal method,using Co(NO3)2-6H2O and thiourea as raw materials.Composition,particle size and surface morphology of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results show that the as-prepared material are CoS nanoparticles at 180 ℃,witch diameter is about 40 nm.Powder production rate increases with increasing temperature,when the reaction temperature rises to 180 ℃,the yield close to 60%.When temperature further increases to 200 ℃,the yield remains unchanged,but abnormal grain growth happened.Addition of dispersant PEG can effectively control the size of the particles and inhibit the reunite of products.In additions,higher degree of crystallinity of the CoS nanocrystals can be synthesized by reducing the content of organic solvent EG,but it is not beneficial to control powder particle size,because the reaction rate is too fast.