纳米氧化锌的制备及其在太阳光下的光催化性能

Preparation of ZnO Nanoparticles and Their Catalytic Property under Solar Light

本文以醋酸锌、浓氨水为原料,采用均匀沉淀法,制备了在太阳光下具有优良光催化性能的纳米氧化锌粉体,并利用透射电镜(TEM)、UV-Vis、X射线衍射(XRD)和ξ电位对所得样品进行了表征;以亚甲基蓝(MB)溶液的光催化脱色降解为模型反应,考察了煅烧温度对其结构与催化性能的影响。研究结果表明:在150℃下煅烧4h得到了具有良好分散性和结晶性能的纳米氧化锌粒子,粒径分布均匀、平均粒径约10nm;该纳米材料在太阳光下具有高的光催化活性和稳定性,照射2h可以使MB溶液的脱色率达100%,且重复使用5次时染料的脱色率仍在95%以上;所得样品的ξ电位均为负值,样品表面过剩的负电荷源自于样品的结构缺陷,即Zn2+空位或O2-过剩,且表面电荷量随煅烧温度的不同而不同;结构缺陷是其光谱响应范围的拓展和在太阳光条件下具有良好催化性能等的重要原因。

ZnO nanoparticles with good photocatalytic property under solar light were prepared by cooperationprecipitation method with zinc acetate and ammonia as raw materials. The as-made samples were characterized by TEM, UV-Vis, XRD and ξ potential measurement. Decolorizing of MB dye solution as the model reaction, the effect of calcining temperature on the structure and catalytic property of the samples was examined. Results showed that ZnO nanoparticles with well-dispersion and crystal property, obtained by calcining the precursor at 150 ℃ for 4 h, had the average diameter of about 10 nm, the even particle size distribution, and higher photocatalytic property under solar light. After being illuminated for 2 h under solar light, the decolorizing efficiency of the MB solution reached 100% and the efficiency remained above 95% after being reused for five times. The ξ potential of the samples was negative. Excess negative charge on its surface was related to the structure defect,that was Zn^2＋ vacancy or O^2- excess. And charge quantity changed with calcining temperature. The structure defect was a very important factor of extending the light response of ZnO nanoparticles and improving catalytic property of the samples under solar light.