Ni(OH)2及Co(OH)2片状纳米晶体的合成与表征

使用强碱氢氧化钾为沉淀剂,通过水热法成功合成了具有六角形貌的过渡金属氢氧化物Ni（OH）2及Co（OH）2片状纳米晶.利用X射线粉末衍射仪和透射电子显微镜对样品的结构和形貌进行了表征.透射电镜观察结果显示：Ni（OH）2相为规则六角纳米片,Co（OH）2相为纳米片和纳米棒的混合物.选区衍射结果指出：Ni（OH）2及Co（OH）2纳米晶体均为单晶体.Ni（OH）2及Co（OH）2纳米片的产率分别达到了70%和90%.将实验结果同前人的过渡族金属氢氧化物纳米片报道进行了比较,提出了一个新的片状纳米晶的形成机制,指出在正常的沉淀条件下,Ni（OH）2及Co（OH）2纳米晶的稳定形貌总为六角片状.

Synthesis and characterization of Ni (OH) 2 and Co (OH) 2 nano-sheet crystals

Transition metal hydroxides Ni(OH)_2 and Co(OH)_2 nano-sheet crystals with hexagonal morphology have been successfully synthesized through hydrothermal method using strong alkali(KOH) as precipitator.The structure and morphology of the as-prepared samples were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM).TEM observations exhibit that the Co(OH)_2 phase is formed with the regular hexangular nano-sheets,while Ni(OH)_2 phase a mixture of nano-sheets and nano-rods.Selected area electron diffraction(SAED) patterns reveal the single crystalline nature of the entire nano-sheet.The yields of the nano-sheets for Ni(OH)_2 and Co(OH)_2 reach about 70% and 90%,respectively.It is proposed that hexagonal sheet is a stable crystalline morphology for the current solid compounds under normal precipitation conditions.Comparing with the previous reports on synthesis of transition metal hydroxide nano-sheet by the other methods,a new formation mechanism of nano-sheets has been discussed.