Synthesis and Exfoliation of Co2+-Fe3+ Layered Double Hydroxides: An Innovative Topochemical Approach
作者：Renzhi Ma,* Zhaoping Liu, Kazunori Takada, Nobuo Iyi, Yoshio Bando, Takayoshi Sasaki
關鍵字：layered double hydroxides
論文來源：期刊
具體來源：J. Am. Chem. Soc. 2007, 129, 5257-5263.
發表時間：2007年
This paper describes a topochemical synthetic approach to Co2+-Fe3+ layered double hydroxides (LDHs). Micrometer-sized hexagonal platelets of brucite-like Co2/3Fe1/3(OH)2 were first prepared by a homogeneous precipitation of an aqueous solution of divalent cobalt and ferrous ions through hexamethylenetetramine (HMT) hydrolysis under a nitrogen gas atmosphere. A subsequent oxidative intercalation process, by the action of iodine (I2) in chloroform (CHCl3), transformed the precursory brucite-like Co2+-Fe2+ hydroxides into hydrotalcite-like Co2+-Fe3+ LDHs, in which the oxidization of Fe2+ into Fe3+ induced positive charges to the octahedral hydroxyl layers while anions (I-) were intercalated into the interlayer space. Co2+-Fe3+ LDHs inherited the high crystallinity and hexagonal platelet morphology from their brucitelike precursor due to the topotactic nature of the transformation, which was verified by abundant microscopic and spectroscopic characterizations. After a normal ion-exchange process, Co2+-Fe3+ LDHs accommodating perchlorate anions were exfoliated into unilamellar nanosheets in formamide by an ultrasonic treatment.