阴离子柱撑磁性镍铝水滑石的制备及表征

Synthesis and Characterization of Magnetic Anion-pillared Ni-Al Hydrotalcites

将磁性基质与镍铝类水滑石组装制备磁性镍铝水滑石。研究了磁性基质含量、焙烧温度对水滑石磁学性能及结构的影响。并采用SEM、XRD、FT-IR、DSC-TG及VSM(vibrating sample magnetometer)等测试技术对制备的水滑石的结构和磁学性能进行了表征。结果表明,磁性基质的引入赋予镍铝类水滑石以超顺磁性,磁性基质含量对样品的磁性能起决定性作用,磁性镍铝水滑石的比饱和磁化强度随磁性基质含量的增加而增加;XRD分析结果表明,磁性基质的引入没有改变水滑石的典型层状结构且随着磁性基质含量的增多,磁性镍铝水滑石的特征衍射峰的衍射强度有所降低,n(Ni2+)/n(Fe2+)达到20时,XRD谱图中开始出现Fe3O4晶相的衍射峰;前驱体经1073K焙烧后出现尖晶石晶相;DSC-TG分析结果表明,磁性基质的引入没有改变水滑石2个阶段吸热的特征,这与XRD的检测结果一致。

Magnetic Ni-Al hydrotalcites were synthesized with different amounts of magnetic substrate and Ni- Al hydrotalcite-like compounds. The influences of the amount of magnetic substrate, calcination temperature on the structure were studied. The obtained samples were characterized by SEM, XRD, FT-IR, DSC-TG, and VSM. The results indicate that the introduction of magnetic substrate endows Ni-Al hydrotalcite a super-magnetism feature. The magnetism depends on the amount of the magnetic substrate. The saturation magnetization of magnetic Ni-Al hydrotalcite is enhanced with the increasing of magnetic substrate. X-ray diffraction patterns show the layered structures of magnetic Ni-Al hydrotalcites are not affected by introducing a certain amount of magnetic substrate and the diffraction peaks decrease with increasing the amount of magnetic substrate. When the n（Ni^2＋ ）/n（ Fe^2＋ ） molar ratio reaches 20, XRD diffraction peaks of the Fe3O4 phase begin to emerge. When the temperature is increased to 1 073 K, the spinel phase is observed. The DSC-TG curves show two endothermal peaks are not affected by introducing magnetic substrate, and is consistent with XRD result.