微/纳米ZnO的控制合成及其光催化性能

摘要

以锌盐和碱为主要原料,采用低温液相法,通过控制反应前驱液的组成,制得针状、花状、棒状和枣核状4种不同形貌的微/纳米ZnO.利用扫描电子显微镜(SEM)、X线能谱仪(EDS)、X线粉末衍射仪(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)和热重-差热分析(TG-DTA)等多种手段对产物进行表征,并探讨不同形貌ZnO微/纳米晶的形成机制.以甲基橙模拟有机污染物,考察紫外光照下所得ZnO样品的降解效果.研究结果表明:ZnO晶体的粒度和形貌由其生长习性及成核、生长速率共同控制.ZnO的光催化性能与其颗粒粒度及形貌密切相关,棒状和枣核状ZnO表现出很高的光催化活性,120 min内即可将甲基橙完全降解.%Using zinc chloride and sodium hydroxide as the reactants, needle-, flower-, rod- and jujubestone-like ZnO micro-/nano-crystals were prepared via a low-temperature liquid phase method by controlling the composition of precursor solution. SEM, EDS, XRD, FT-IR, UV-Vis DRS and TG-DTA were used to characterize the products. Possible formation mechanism for these ZnO micro-/nanocrystals with different morphologies was discussed. The as-prepared ZnO powders were applied in photocatalytic degradation of methyl orange as model of organic pollutant during UV irradiation. The results show that the size and morphology of ZnO crystal are determined by its growth habit as well as nucleation and growth rates. A close relationship exists between the photocatalytic performance and the particle morphology and size. Rod- and jujubestone-like ZnO exhibit very strong photocatalytic activity, and methyl orange was completely degraded within 120 min.