Stoichiometric synthesis of pure MFe2O4 (M = Mg, Co, and Ni) spinel ferrites from tailored layered double hydroxide (hydrotalcite-like) precursors
Stoichiometric synthesis of pure MFe2O4 (M = Mg, Co, and Ni) spinel ferrites from tailored layered double hydroxide (hydrotalcite-like) precursors
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DOI：
10.1021/cm035248c
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发表时间：
2004-04-20
影响因子：
8.6
通讯作者：
Duan, X
中科院分区：
文献类型：
--
作者：
Li, F;Liu, JJ;Duan, X
本文报道了一种新的合成纯MFe_2 O_4（M = Mg，Co，Ni）尖晶石铁氧体的方法。该方法的关键特征是使用单分子前体。纯尖晶石铁氧体可以通过煅烧[M1-X-YFeY 2 + FeX 3+（OH）（2）]（X+）（SO 4 2-）（X/2）.mH（2）O型水滑石类层状双氢氧化物（LDHs）来获得（M = Mg、Co和Ni）前体在900 ℃下反应2小时，其中M2+/（Fe 2 + + Fe 3+）的摩尔比被调节到与单一尖晶石铁氧体本身相同的值。通过X射线粉末衍射（XRD）、化学分析、傅里叶变换红外光谱（FT-IR）、热重-差热分析（TG-DTA）和穆斯堡尔谱等手段对合成的LDHs及其煅烧产物的结构特征进行了表征。尽管材料的组成相似，但通过煅烧LDH制备的材料的饱和磁化强度高于通过常规陶瓷和湿化学路线制备的尖晶石铁氧体。新方法的主要优点是它提供了LDH前体中原子水平上所有金属阳离子的均匀分布;因此，从LDH开始形成尖晶石铁氧体需要低得多的温度和更短的时间，从而降低了副反应发生的机会。
In this paper a novel synthetic route of pure MFe2O4 (M = Mg, Co, and Ni) spinel ferrites is reported. The key feature of this method is using a single molecular precursor. The pure spinel ferrites can be obtained by calcination of tailored hydrotalcite-like layered double hydroxides (LDHs) of the type [M1-X-YFeY2+FeX3+(OH)(2)](X+)(SO42-)(X/2).mH(2)O (M = Mg, Co, and Ni) precursors at 900 degreesC for 2 h, in which the molar ratio of M2+/(Fe2+ + Fe3+) is adjusted to the same value as that in single spinel ferrite itself. The structural characteristics of the as-synthesized LDHs and their resulting calcined products are obtained by powder X-ray diffraction (XRD), chemical analysis, Fourier transform infrared spectroscopy (FT-IR), simultaneous thermogravimetric and differential thermal analysis (TG-DTA), and Mossbauer spectroscopy. The saturation magnetizations of the materials produced by calcinations of LDHs are higher than those of the spinel ferrites produced by the conventional ceramic and wet chemical routes, although the compositions of the materials are similar. The major advantage of the new method is that it affords uniform distribution of all metal cations on an atomic level in the LDH precursors; hence, the formation of spinel ferrites starting from the LDHs requires a much lower temperature and shorter time, leading to a lower chance of side-reactions occurring.