Co_3O_4纳米晶的制备和表征

The Synthesis and Characteristic of Co_3O_4 Nanocrystals

发现了一种新制备Co3O4纳米晶的新方法。这种方法是先将高分子聚乙烯吡咯烷酮(PVP)和乙酸钴溶解到溶剂中缓慢蒸发溶剂,然后干燥形成的前驱体,最后在400℃温度下煅烧制备了Co3O4纳米晶。生成的产物用XRD,SEM,TEM等测试方法进行了表征。结果发现在不同的溶剂中形成前驱体所制备的Co3O4纳米晶具有不同的形貌特征,使用乙醇溶剂时生成了大量的由Co3O4纳米晶自组装形成的Co3O4微米球;而使用水溶剂时则生成的全都是Co3O4纳米晶。实验结果表明在不同溶剂中形成的前驱体对于最终制备的Co3O4纳米晶形态有着很大的影响。

The authors found a new method to synthesize Co3O4 nanocrystals, which were synthesized using Co(CH3COO)2·4H2O and PVP as precursor. The as-prepared products were measured by SEM, TEM and XRD. Co(CH3COO)2·4H2O and PVP were dissolved together in a kind of solvent. Then, the solution was vaporized in water bath at 60°C till the solution became viscid. The viscid solution was transferred into a ceramic boat and was dried in a oven at 110°C for 12 hours. Finally, the dried sample was calcined in tube-like stove at 400°C for 2 hours in air to produce the Co3O4 nanocrystals. To prepare the precursor composed of PVP and Co(CH3COO)2·4H2O, the authors employed two different solvent (ethanol and H2O). It was found that different appearance of Co3O4 nanocrystals was achieved by using different solvent. When ethanol is used as solvent, the prepared spherical particles with diameter of about 1 μm were consisted of Co3O4 nanocrystals with diameter of 20-50 nm. However, only Co3O4 nanocrystals with diameter of 20 nm were synthesized when H2O is used as solvent. This indicated that the solvent played a big role for the final appearance of nanocrystals.