Liu Zhaoping, Ma Renzhi, Osada Minoru, Takada Kazunori, Sasaki Takayoshi
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
J Am Chem Soc. 2005 Oct 12;127(40):13869-74. doi: 10.1021/ja0523338.
We report on the controlled synthesis of single-crystal platelets of alpha- and beta-Co(OH)2 via homogeneous precipitation using hexamethylenetetramine as a hydrolysis agent. The alpha- and beta-Co(OH)2 hexagonal platelets of several micrometers in width and about 15 nm in thickness were reproducibly yielded in rather dilute CoCl2 solutions in the presence and absence of NaCl at 90 degrees C, respectively. The phase and size control of the products were achieved by varying both CoCl2 and NaCl concentrations. Polarized optical microscope observations revealed clear liquid crystallinity of colloidal suspensions of these high aspect-ratio platelets. The as-prepared alpha-Co(OH)2 containing interlayer chloride ions was intercalated with various inorganic or organic anions, keeping its high crystallinity and hexagonal platelike morphology.
我们报道了通过以六亚甲基四胺作为水解剂的均匀沉淀法来可控合成α-和β-Co(OH)₂单晶片。分别在90℃下，在有和没有NaCl存在的相当稀的CoCl₂溶液中，可重复地得到宽度为几微米且厚度约为15nm的α-和β-Co(OH)₂六角形片。通过改变CoCl₂和NaCl的浓度实现了产物的相和尺寸控制。偏振光学显微镜观察揭示了这些高纵横比片的胶体悬浮液具有明显的液晶性。所制备的含有层间氯离子的α-Co(OH)₂被各种无机或有机阴离子插层，同时保持其高结晶度和六角形片状形态。
