Abstract

Zinc-aluminum based layered double hydroxide (ZnAl-LDH), -oxide (ZnO), -mixed oxide (Zn₆Al₂O₉), and zinc-aluminum mixed oxide/polyvinyl alcohol (ZnAl-mixed oxide/PVA) nanocomposite have been synthesized. The samples were characterized using some analytical methods: Ultraviolet-visible spectroscopy, Fourier transforms infrared (FTIR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The XRD patterns of ZnAl-LDH_5M and ZnAl-LDH_2M show the characteristic reflections of ZnO phase beside the hydrotalcite-like structure. Using NaHCO₃ in the experiment, the precipitation speed of the sample was high and in this regard, the particle size of ZnAl-LDH_urea(1) was 22.37 nm. ZnAl-LDH_2M and ZnAl-LDH_5M describe three optical band gaps with three different energies. For ZnAl-mixed oxide/PVA, there are two types of electronic transitions could exist at ZnO which attributed to the filled O2p orbital and that associated to the empty Zn 4s orbital, with the possibility of some Zn 4p orbital. Another electronic transition could exist for Zn₆Al₂O₉ between the filled O 2p orbital and the empty Al 3s orbitals, with the additional possibility of some Al 3p orbital. The intense FTIR band at very low wavenumber is observed for only ZnAl-LDH_urea(2) which attributed to the Zn-O-bound for brucite-like LDH structures.

摘要

锌铝基层状双氢氧化物（ZnAl-LDH）、-氧化物（ZnO）、-混合氧化物（Zn ₆ Al ₂ O ₉）和锌铝混合氧化物/聚乙烯醇（ZnAl-混合氧化物/PVA）纳米复合材料具有被合成。使用一些分析方法对样品进行了表征：紫外-可见光谱、傅里叶变换红外 (FTIR) 光谱、X 射线衍射 (XRD)、扫描电子显微镜和能量色散 X 射线光谱。_{ZnAl-LDH 5M}和ZnAl-LDH _2M的XRD图谱显示除了类水滑石结构外还有ZnO相的特征反射。使用 NaHCO _{3在实验中，样品的沉淀速度很高，在这方面，ZnAl-LDH尿素（1）}的粒径为22.37 nm。ZnAl-LDH _2M和 ZnAl-LDH _5M描述了具有三种不同能量的三个光学带隙。对于ZnAl-混合氧化物/PVA，在ZnO处可能存在两种类型的电子跃迁，它们归因于填充的O2p轨道和与空Zn 4s轨道相关的电子跃迁，并且可能存在一些Zn 4p轨道。_{Zn 6} Al ₂ O ₉可能存在另一种电子跃迁在填充的 O 2p 轨道和空的 Al 3s 轨道之间，还有一些 Al 3p 轨道的额外可能性。_{仅 ZnAl-LDH尿素 (2)}观察到在非常低的波数下的强 FTIR 波段，这归因于水镁石样 LDH 结构的 Zn-O 结合。