利用拉曼光谱方法, 对柠檬酸钠辅助水热合成纳米结构多孔ZnO微球的机理进行了研究。 样品的拉曼光谱特征显示, 多孔ZnO微球中存在Zn-柠檬酸配合物; 分析表明反应溶液中柠檬酸钠水解产生的柠檬酸根与Zn2+结合形成Zn-柠檬酸配合物, 该配合物化学吸附在Zn(OH)2晶核的(204)和(503)晶面, 使Zn(OH)2晶核择优生长形成纳米薄片状结构; 水热过程中Zn(OH)2微晶团聚形成纳米片状结构多孔Zn(OH)2微球并以沉淀析出。 研究发现吸附在薄片表面的Zn-柠檬酸配合物提高了Zn(OH)2微晶的热稳定性, 使得Zn(OH)2的分解温度高于200 ℃, 加热到300 ℃后Zn(OH)2完全分解获得纳米结构多孔ZnO微球。

Raman spectrum was applied to analyze the synthesis mechanism of nanostructure porous ZnO microspheres prepared via hydrothermal method assisted with trisodium citrate. The Raman spectrum characteristics of the sample revealed that the ZnO microspheres contained Zn-citrate complex, which was the complex of citrate acid group and Zn2+ in the reaction solution. The complex was chemisorbed on (204) and (503) faces of the Zn(OH)2 crystallite in the reacting solution, resulting in Zn(OH)2 nanosheet from the crystallite. Large quantities of Zn(OH)2 nanosheets aggregated as porous microspheres in hydrothermal process. Zn-citrate complex chemisorbed on the nanosheet improved the thermal stability of Zn(OH)2, which means a decomposition temperature over 200 ℃. Nanostructure porous ZnO microspheres were obtained by heating Zn(OH)2 microspheres at 300 ℃ and the nanosheet structure was maintained.