稀土功能材料的超声化学制备及其性能研究
发布时间：2019-05-09 01:59
【摘要】：近年来纳米材料的制备方法研究逐渐成为科学热点之一。在众多的制备方法中,超声化学法在纳米材料的制备中表现出独特的性能。本论文利用超声溶胶-凝胶法制备了稀土β-二酮配合物掺杂的二氧化硅凝胶以及稀土 Pr3+掺杂的二氧化钛纳米材料,并通过光声光谱(PA)、荧光光谱(PL)、X射线衍射(XRD)等表征手段对超声制备的样品性能进行了研究,同时研究了室温离子液体溶剂中的超声空化机理。本论文主要由六个章节组成:第一章简要地概述了纳米材料的分类、特性和相关的常见制备方法。介绍了声化学及其在纳米材料制备中的应用,分析了超声化学法制备纳米材料的内在机理,即超声空化效应。并给出本课题的研究内容及意义所在。第二章介绍了纳米材料的分析方法,包括X射线衍射分析(XRD)、荧光光谱(PL)、透射电子显微学(TEM)和光声光谱法(PAS)。并着重回顾了光声光谱技术的历史背景、基础理论和应用领域等。第三章介绍了稀土配合物的光致发光现象,并通过超声溶胶-凝胶法将稀土β-二酮配合物 Ln(btfa)3·2H2O(Ln3+:Eu3+,Sm3+,Tb3+btfa:4,4,4-三氟-1-苯基-1,3-丁二酮)掺杂到二氧化硅凝胶中,采用光声光谱对稀土配合物在凝胶中的形成进行研究。结果表明,对于仅在室温下陈化,干燥的湿凝胶样品,在β-二酮配体吸收处的光声强度几乎完全相同。然而,在经过150℃热处理后,Eu3+、Sm3+、Tb3+配合物掺杂的凝胶样品在配体吸收处的光声强度依次增强,不同的光声强度通过荧光光谱的分析得到了解释,荧光光谱的分析结果与光声光谱基本一致,结果表明稀土β-二酮配合物在没有经过适当热处理的硅凝胶中不能形成。最后,基于光声光谱和荧光光谱的结果提出了样品的激发驰豫模型。第四章,首先介绍了纳米二氧化钛材料的研究进展以及稀土离子掺杂二氧化钛的优良特性。然后通过超声溶胶-凝胶法制备了 Pr3+掺杂的二氧化钛纳米材料,并通过使用Pr3+离子作为光声探针来研究相变期间样品结构的变化。结果表明,对于在80℃下加热的凝胶样品,Pr3+的配位环境与其水相离子相似,Pr3+的f-f跃迁随着凝胶到锐钛矿的转变展现出了持续的红移,说明Pr3+键的"共价性"增加。然而,对于在ll00℃下锻烧的样品,Pr3+的f-f跃迁显示出明显的蓝移,这可归因于在锐钛矿到金红石转变期间Pr3+离子与外表面分离,形成Pr4Ti9O24。最后还讨论了掺杂的Pn3+离子对样品的锐钛矿相的稳定作用。第五章,介绍了液体中的超声空化机理,以Flynn修正的R-P声空化方程对室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF4])中的空化机理进行了空化动力学数值模拟,分析了超声驱动声压幅值、驱动频率、空化气泡的初始半径等相关参数对空化效应的影响,并且研究了在变温情况下离子液体中的独特的空化特性。第六章,对全文的工作进行总结,并对今后的工作进行展望。
[Abstract]:In recent years, the preparation of nano-materials has gradually become one of the scientific hotspots. Among the many preparation methods, ultrasonic chemistry shows unique properties in the preparation of nano-materials. In this paper, silica gel doped with rare earth 尾-diketone complex and TIO _ 2 nano-material doped with rare earth Pr3 were prepared by ultrasonic sol-gel method. The (PL), fluorescence spectra of rare earth 尾-dione complex and rare earth doped titanium dioxide were obtained by photoacoustic spectroscopy (PA),). The properties of the samples prepared by ultrasound were studied by X-ray diffraction (XRD) and the mechanism of ultrasonic cavitation in room temperature ionic liquids was also studied. This paper mainly consists of six chapters: chapter one briefly summarizes the classification, properties and related common preparation methods of nano-materials. The sonochemistry and its application in the preparation of nano-materials are introduced. The intrinsic mechanism of ultrasonic chemical synthesis of nano-materials is analyzed, I. E., ultrasonic cavitation effect. The research content and significance of this topic are also given. In chapter 2, the analytical methods of nano-materials are introduced, including X-ray diffraction analysis of (XRD), fluorescence spectrum, (PL), transmission electron microscopy (TEM) and photoacoustic spectroscopy (PAS). The historical background, basic theory and application fields of photoacoustic spectroscopy are reviewed. In chapter 3, the photoluminescence of rare earth complexes Ln (btfa) 3 路2H2O (Ln3: Eu3, Sm3, Tb3 btfa:4,4,) was studied by ultrasonic sol-gel method. 4-trifluoro-1-phenyl-1, 3-butanedione (4-trifluoro-1-phenyl-1, 3-butanedione) was doped into silica gel. The formation of rare earth complexes in silica gel was studied by photoacoustic spectroscopy. The results show that the photoacoustic intensity of dry wet gel samples aged only at room temperature is almost the same at the absorption site of 尾-Dione ligand. However, after heat treatment at 150 鈩，
本文编号：2472391
[Abstract]:In recent years, the preparation of nano-materials has gradually become one of the scientific hotspots. Among the many preparation methods, ultrasonic chemistry shows unique properties in the preparation of nano-materials. In this paper, silica gel doped with rare earth 尾-diketone complex and TIO _ 2 nano-material doped with rare earth Pr3 were prepared by ultrasonic sol-gel method. The (PL), fluorescence spectra of rare earth 尾-dione complex and rare earth doped titanium dioxide were obtained by photoacoustic spectroscopy (PA),). The properties of the samples prepared by ultrasound were studied by X-ray diffraction (XRD) and the mechanism of ultrasonic cavitation in room temperature ionic liquids was also studied. This paper mainly consists of six chapters: chapter one briefly summarizes the classification, properties and related common preparation methods of nano-materials. The sonochemistry and its application in the preparation of nano-materials are introduced. The intrinsic mechanism of ultrasonic chemical synthesis of nano-materials is analyzed, I. E., ultrasonic cavitation effect. The research content and significance of this topic are also given. In chapter 2, the analytical methods of nano-materials are introduced, including X-ray diffraction analysis of (XRD), fluorescence spectrum, (PL), transmission electron microscopy (TEM) and photoacoustic spectroscopy (PAS). The historical background, basic theory and application fields of photoacoustic spectroscopy are reviewed. In chapter 3, the photoluminescence of rare earth complexes Ln (btfa) 3 路2H2O (Ln3: Eu3, Sm3, Tb3 btfa:4,4,) was studied by ultrasonic sol-gel method. 4-trifluoro-1-phenyl-1, 3-butanedione (4-trifluoro-1-phenyl-1, 3-butanedione) was doped into silica gel. The formation of rare earth complexes in silica gel was studied by photoacoustic spectroscopy. The results show that the photoacoustic intensity of dry wet gel samples aged only at room temperature is almost the same at the absorption site of 尾-Dione ligand. However, after heat treatment at 150 鈩，
本文编号：2472391
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