Preparation Of Hydrotalcite-Like Materials And Research On Structure

Layered double hydroxides (LDHs), also called hydrotalcite like compound (HTlc), is a typical anions layer materials. In this thesis, the influence of different synthetic methods and preparative conditions on the structure and crystallinity of some typical HTlc has been investigated systematically. The crystal structures of some high-crystallinity products are refined by the X-ray diffraction Rietveld refinement method, their crystal models are upbuilt.Theα-cobalt hydroxides are synthesized by the hydrolysis of urea. The influence of reaction atmosphere, concentration of urea and reaction time on the crystal structure, crystallinity and morphology ofα-cobalt hydroxides has been investigated. Besides the nomal flat sheets and nanorods morphologies, We also synthesize the product with chrysanthemum morphology. Spinel Co₃O₄ with the same morphology are achieved by thermal decomposition ofα-cobalt hydroxides. The high-crystallinity ofα-cobalt hydroxides can be synthesized by hydrolysis of hexamethyleneteramine.In bi-metal HTlc systems, we discuss the influence of synthesis methods and conditions on the crystallinity of Zn-Al-CO₃-LDHs, Mn-Al-Cl-LDHs and Mg-Mn-CO₃-LDHs. Based on the research, we gain the high-crystallinity Zn-Al-CO₃-LDHs, which is fit to the structure refinement.Through the X-ray powder diffraction Rietveld refinement, we get the specific crystal parameters of Zn-Al-CO₃-LDHs andα-cobalt hydroxides, and build up the crystal structure models.