电合成系列锌配合物及纳米ZnO的制备

Electrochemical Synthesis of Zinc Complexes and Preparation of Nano-sized ZnO

采用锌金属为“牺牲”阳极 ,首次在无隔膜电解槽中 ,电化学一步法制备了纳米ZnO前驱体锌配合物Zn(OEt) 2 ,Zn(OBu) 2 ,Zn(acac) 2 ,Zn(OEt) 2 (acac) 2 ,Zn(OBu) 2 (acac) 2 (acac为乙酰丙酮基 ) ,产物通过红外光谱 (FT IR)、拉曼光谱和核磁共振进行表征 .同时采用含Zn(OEt) 2 (acac) 2 的电解液直接水解制备纳米ZnO粉体 ,纳米ZnO通过拉曼光谱、X射线粉末衍射 (XRD)和透射电子显微镜 (TEM)进行表征 .实验表明电解时防止阳极钝化 ,控制温度在 5 0～ 6 0℃之间 ,采用有机胺溴化物为导电盐 ,可以提高电合成效率 ;电解合成Zn(acac) 2 ,Zn(OEt) 2 (acac) 2 ,Zn(OBu) 2 (acac) 2 的电流效率比Zn(OEt) 2 ,Zn(OBu) 2 高 ,其中Zn(OEt) 2 (acac) 2 适宜作为溶胶 -凝胶法制备纳米ZnO的原料 ,制备得到的纳米ZnO经 6 0 0℃煅烧后呈球形单分散结构 ,平均粒径在 5～ 10nm左右 .

Zinc complexes were directly prepared by using zinc metal as sacrificing anode in a cell without separating the cathode and anode spaces. The products were characterized by using FT-IR, NMR and Raman spectroscopy. The influence of temperature and conductive additives on product yield was also investigated. The study shows that direct electrochemical preparation of zinc complexes such as Zn(acac)(2), Zn(OEt)(2) (acac)(2) and Zn(OBu)(2)(acac)(2) has high current efficiency and electrolysis yield than that of Zn(OR)(2). Furthermore, these zinc complexes have high purity and can be directly used as sol-gel precursor for preparation of nanometer ZnO. Experimental results show that controlling temperature in the range of 50 similar to 60 degreesC, selecting R4NBr as conductive additives and preventing zinc anode from being covered by electrochemical products can improve product yield. The study also shows that nano-sized ZnO prepared by this method has monoclinic structure with a narrow size distribution of 5-10 nm.