Growth and Characterization of Octahedral Cobalt Oxide Particles in Supercritical Carbon Dioxide System
Growth and Characterization of Octahedral Cobalt Oxide Particles in Supercritical Carbon Dioxide System
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发表时间：
2008
影响因子：
0.7
通讯作者：
Yang Jun
中科院分区：
文献类型：
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作者：
Yang Jun
研究了正八面体氧化钴颗粒在超临界二氧化碳体系中的合成过程.在1.0g醋酸钴粉和12.0g干冰组成的密闭容器中，于450 ℃下制备了尺寸约为10 μm的规则八面体氧化钴微晶。采用XRD、XPS、SEM、TEM和拉曼光谱等手段对所制备的纳米粒子进行了表征。XRD和拉曼光谱结果表明，所制备的氧化钴微晶具有规则的晶体结构。SEM和TEM结果表明，氧化钴微晶的形貌为八个{111}面围成的正八面体。条件实验显示,超临界二氧化碳体系是正八面体氧化钴颗粒合成的充分条件.氧化钴微晶的尺寸随反应时间的延长而增大，其形貌与温度有关。基于醋酸钴（Ⅲ）的热分解、氧化钴的晶化和超临界CO2环境中各向异性引起的缓慢取向生长（SOG），讨论了正八面体氧化钴微晶的可能生长机理。并对正八面体氧化钴微晶电池材料的充放电性能进行了表征和讨论。
The synthesis of regular octahedron cobalt oxide microcrystals for the application of battery material in supercritical carbon dioxide system was studied. Regular octahedron microcrystals of cobalt oxide with a size about 10 μm were prepared at 450 ℃ in a closed vessel consisting of 1.0 g of cobalt acetate powder and 12.0 g of dry ice. The as-obtained particles were charterized by XRD, XPS, SEM, TEM and Raman spectroscopy techniques. The XRD and Raman spectroscopy results indicate that the crystal structures of the particles (the cobalt oxide microcrystals) are inerratic. SEM and TEM results reveal that the morphology of cobalt oxide microcrystals appear to be the regular octahedron enclosed by eight {111} facets. It is found that the supercritical carbon dioxide system is a full condition to the synthesis of regular octahedron cobalt oxide. The size of cobalt oxide microcrystals increases with reaction time and the morphology is temperature dependent. The possible growth mechanism of regular octahedron cobalt oxide microcrystals was discussed based on the pyrolysis of cobalt (Ⅲ) acetate, crystallization of cobalt oxide and Slowly Orientational Growth (SOG) due to anisotropy in supercritical carbon dioxide environment at reaction temperatures. The charge/discharge properties of regular octahedron microcrystals of cobalt oxide used as battery material were also characterized and discussed.