溶剂热法合成CoS纳米晶及其表征

Solvothermal synthesis and characterization of cobalt sulfide nanocrystals

以六水合硝酸钴(Co(NO3)2.6H2O)和硫脲为原料,采用混合溶剂热法制备硫化钴(CoS)纳米晶。利用X射线衍射(XRD),扫描电镜(SEM)和透射电镜(TEM)对硫化钴纳米晶的组成、粒径及表面形貌进行表征。结果表明,在180℃恒温条件下所得粉末样品为六方相CoS纳米粉末,粉末粒径在40 nm左右。粉末的产率随温度升高而增大,当反应温度上升到180℃时产率接近60%;温度进一步升高到200℃时产率基本不变,但晶粒异常长大。加入分散剂PEG能有效控制粉末颗粒的尺寸并抑制粉末的团聚;此外,减少有机溶剂EG的含量可获得更高结晶度的CoS纳米晶,但由于反应速率过快,不利于控制粉末的粒径。

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.