【摘要】 报道一种非常简单的制备NiO和Ni(OH)2空心微球的无模板水热法,即通过NiCl2与氨水在140℃水热反应12h,制备了Ni(OH)2纳米片自组装的空心微球,经400℃热处理2h得到了NiO空心微球.采用X射线衍射仪、扫描电镜和透射电子显微镜对产物进行表征,并在室温下测试了它的磁学性能,结果表明,Ni(OH)2空心微球的直径约为3～4μm,它是由尺寸1.1～1.3μm左右的六方相结构的Ni(OH)2纳米片组装而成;NiO空心微球是由立方相纳米片和多孔纳米片组装而成,它具有弱的铁磁性,其矫顽力为583Oe,剩余磁化强度为0.213emu/g.研究了氨在Ni(OH)2纳米片的形成与组装过程中的作用,提出了可能的生长机理.更多还原

【Abstract】 In this work, we report a very simple template-free hydrothermal approach to prepare hollow Ni(OH)2 and NiO microspheres. The hollow Ni(OH)2 microspheres were prepared via the hydrothermal re- action of NiCl2 with aqueous ammonia at 140 ℃ for 12 h. Subsequently, the similar microstructured NiO hollow microspheres were obtained by calcining the above precursor at 400 ℃ for 2 h. The as-synthesized products were characterized by means of powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the hollow Ni(OH)2 microspheres with the di- ameters of 3～4 μm are constructed from 2-dimensional Ni(OH)2 nanosheets with the hexagonal structure and dimensions of 1.1～1.3 μm. The hollow NiO microspheres are co-constructed from NiO nanosheets and porous nanosheets with the cubic structure. Magnetic properties of the hollow NiO microspheres have been detected by a vibrating sample magnetometer at room temperature. It was found that the NiO microspheres exhibit weak ferromagnetism. The coercive force and remanent magnetization are 583 Oe and 0.213 emu/g respectively. The role of the ammonia in the growth and self-assembly of Ni(OH)2 nanosheets was investi- gated, and a possible mechanism was also proposed to account for the formation and conversion of Ni(OH)2 nanosheet-based hollow microspheres into NiO hollow microspheres.更多还原