【作者】 马磊；

【导师】 李新勇；

【作者基本信息】 大连理工大学 ， 环境工程， 2006， 硕士

【摘要】 在锌片基底上利用热氧化法，简单低温湿化学法和热氧化-湿化学法制备了不同结构的纳米ZnO。结合XRD、SEM、DRS表征手段对制备的样品进行结构和表面特性分析。在不同的温度下热氧化，制备了具有六方钎锌矿结构的纳米ZnO粒子膜，而用低温湿化学法和热氧化-湿化学法制备了具有高度取向性的六方钎锌矿结构的ZnO纳米棒阵列膜。制备的ZnO纳米棒垂直于金属锌片基底生长且有良好的c轴取向性，纳米棒顶端直径在100 nm-150 nm之间。热氧化-湿化学法制备的纳米棒在锌片表面更致密、排列更加有序、取向性更好。在PL谱中，观察到直接湿化学法制备的ZnO纳米棒阵列薄膜具有良好的发光性能，在379 nm附近发出强的荧光，吸收带边在378 nm附近，禁带宽度为Eg=3.28 eV。而350℃热氧化-湿化学法制备的ZnO纳米棒具有三个荧光发射带，中心波长分别位于386 nm的紫带、524 mm的绿带和450 nm-500 nm附近的蓝带。 光催化实验结果表明，经过350℃热氧化-湿化学法制备的ZnO纳米棒表现出较好的光催化活性，且在此条件下制备的催化剂的光吸收能力最强。这可能是由于合适温度的热氧化抑制了催化剂的光生空穴-电子对的复合。随着光催化反应初始浓度地增高，反应速率减小，光催化的动力学常数与甲基橙溶液的pH有关，并且ZnO纳米棒光催化甲基橙反应呈明显的一级动力学特征。 综上所述，应用简单低温方法在廉价易得的锌片上制备出高性能的ZnO纳米棒阵列。这种简单制备方法为寻找高性能的光催化剂提供了一条有利的途径。更多还原

【Abstract】 Nanostructure zinc oxides (ZnO) on the zinc foils have been combined by thermal oxidation and low-temperature wet-chemical approach. XRD, SEM, DRS are used to characterize the structure and surface chemical-physical properties of the prepared samples. It is indicated that hexagonal ZnO particle-film can be prepared by thermal oxidation method at different temperatures, whereas, highly oriented ZnO nanorod arrays with hexagonal wurtzite structure are formed by the latter two methods on the zinc foils. It is also found that ZnO nanorods with 100 nm-150 nm in diameter grow highly epitaxial along the c-axis orientation. Moreover, the approach combining thermal oxidation and wet-chemical favors the formation of the denser, ordered epitaxial ZnO nanorods on the surface of zinc foil. Photoluminescence spectra of ZnO nanorod array films with excitation wavelength 350 nm are measured at room temperature. Three emission bands are observed, one being a narrow violet band with central wavelength of 386 nm and the other being wide visible bands with central wavelength of 524 nm, 450 nm, respectively. The room temperature photolum inescence of the as-prepared ZnO films exhibits a strong UV emission at about 379 nm and a weak emission at about 450 nm.The catalytic activities of the as-prepared ZnO are evaluated for the photodegradation of methyl orange in aqueous solution. It is revealed that the reaction follows the first-order reaction kinetics. And ZnO nanorods prepared by the wet-chemical approach followed thermal oxidation at 350oC show the best activity for the photodegradation of dye solution, and the highest photoabsorption ability in our case. It could be resulted from the restraint on the recombination of photo hole/electron after the sample is treated by thermal oxidation at appropriate temperature. The photocatalytic reaction follows the first-order reaction kinetics and the constant of apparent rate is related to the initial concentration of methyl orange.In conclusion, ZnO nanorod arrays with high activity are fabricated on the zinc foils using a cheap and simple low-temperature route. It is a potential approach to develop highly efficient photocatalyst.更多还原