聚丙烯酰胺凝胶法制备纳米ZnO颗粒及其光催化性能

Synthesis of Zn O Nanoparticles via a Polyacrylamide Gel Route and Their Photocatalytic Performance

采用改进的聚丙烯酰胺凝胶法制备了高结晶度的纳米ZnO颗粒,用XRD、SEM、XPS、PL和UVvis等对ZnO颗粒的结构、形貌、光学性质等进行了表征.结果表明样品为六角纤锌矿结构的ZnO;ZnO颗粒呈球形,尺寸在10-50nm之间;颗粒分布均匀,没有明显的团聚现象.UV-vis测试发现ZnO纳米颗粒在200-320nm波长范围存在强烈的吸收;PL测试发现在450-480nm波长范围内有很强的光致发光.在高压汞灯照射下,亚甲基蓝、甲基橙和罗丹明B分别在120、160和180min后降解率达到100%.ZnO纳米颗粒对亚甲基蓝、甲基橙和罗丹明B的降解符合一级动力学模型,亚甲基蓝、甲基橙和罗丹明B降解速率常数分别为：0.0470、0.0210和0.0206min^-1,最后讨论了不同有机染料结构对光催化降解速率的影响.

ZnO nanoparticles with high crystallinity are synthesized through a modified polymer-network gel route. The microstructures,morphologies and optical properties of the obtained samples are characterized by XRD,SEM,XPS,PL and UV-vis. The results indicated that the nanoparticles are wurtzite ZnO with the particle-diameter distribution from 10 to 50 nm,and the nanoparticles are nearly spherical and polydisperse. The sample shows an intense absorption in the UV region. The intense PL peaks for ZnO are observed around 450 and 480 nm. The photocatalytic activity of ZnO is evaluated by the methylene blue（ MB）,methyl orange（ MO） and rhodamine B（ RB） degradation in aqueous solution under a high- pressure mercury lamp. MB,MO and RB are effectively degraded by100% within 120、160 and 180 min,respectively. The decomposition of MB,MO and RB under UV irradiation is fitted according to the first order kinetic model,and the value of degradation rate constants are evaluated to be 0. 047 0,0. 021 0 and 0. 020 6 min^- 1,respectively. Finally,the influence of the chemical structure of different dyes on the photocatalytic degradation rate of ZnO has been discussed.