水热前驱体组成对CoTiO3微晶结构的影响

以三氯化钛溶液、乙酸钴为主要原料,水热法制备CoTiO3微晶,系统研究前驱物pH值及引入不同模板剂(聚乙烯醇PVA、羧甲基纤维素CMC、聚乙二醇PEG、乙二胺四乙酸ED-TA)对产物结构的影响.采用X射线衍射(XRD)表征微晶的物相组成,环境扫描电子显微镜(SEM)表征微晶的形貌.结果显示:弱碱性前躯体可制备出CoTiO3微晶,当pH值为8.0～9.0时,产物结晶性高且不含杂质,显现出六边形片状结构.模板剂的加入促使晶粒长大,以CMC为模板剂时效果最明显;此外模板剂还会影响产物的形貌,当PEG或者EDTA为模板剂时,可导致棒状、多面体形貌颗粒产生.当模板剂为PVA时,CoTiO3微晶形貌基本不变,尺寸有所增大.

Effects of precursor composition on the structure of CoTiO3 microcrystalline prepared by hydrothermal process

CoTiO3 microcrystallines were prepared by hydrothermal processing with TICl3 and Co（CH3COO）2· 4H20 as row materials. The effects of precursor pH and introducing tem- platng agents （PVA, CMC, PEG and EDTA） into precursor on the crystal structure were discussed. The phase composition and morphology of microcrystallines were characterized by XRD and SEM, respectively. The results show that CoTiO3 microcrystalline can be obtained from the weak alkaline precursor：The pH range at 8.0-9.0 is better for crystallization and purity of CoTiO3 ,which shows the hexagonal flake shape. The granularity of CoTiO3 is in creased with the introduction of all kinds of templating agents, especially CMC. PEG and EDTA also affect the grain morphology,which results in rod-like or polyhedral particles to appear. When the templating agent is PVA, CoTiO3 microcrystalline morphology is unchanged, but the size is increased.