【作者】 李坤威；

【导师】 严辉； 汪浩；

【作者基本信息】 北京工业大学 ， 材料物理与化学， 2006， 博士

【摘要】 复合氧化物A₂B₂O₇（A和B为金属）包括具有不同结构的多种化合物,具有优异的光电磁等物理性质,而成为纳米材料领域最富有活力、对未来经济和社会发展有十分重要影响的研究对象,也是纳米科技中最为活跃、最接近应用的重要组成部分。传统的高温固相合成法不仅浪费资源,产物易出现杂项,而且产物尺寸较大。本论文研究重点在于以水热法合成A₂B₂O₇（A=Y,La,Bi;B=Sn,Ti）系列多种纳米复合氧化物,对合成出的产物进行了多种方法的表征,初步研究纳米材料的光催化性质,探索纳米颗粒的尺寸,形貌和化合物的结构变化对光催化性能的影响关系。取得的成果归纳如下:1.设计了一条简单的水热合成路线,成功地运用于A₂B₂O₇（A=Y,La,Bi;B=Sn,Ti）系列多种纳米复合氧化物的合成。2.通过简单的水热法,使用不同的有机试剂（聚甲基丙烯酸甲酯、十六烷基三甲基溴化胺、乙二铵四乙酸二钠盐）,在较低的温度下合成出颗粒尺寸可控的Y₂Sn₂O₇纳米颗粒并对其合成的机理进行了探讨,提出了通过有机试剂来调控Y₂Sn₂O₇的纳米颗粒尺寸的机理。研究了Y₂Sn₂O₇的纳米颗粒大小与光催化性能的关系,发现颗粒半径最小的Y₂Sn₂O₇纳米颗粒光催化效果最好。阐明了纳米颗粒Y₂Sn₂O₇样品具有较高光催化能力的原因。3.为了验证设计的水热合成方法适用于相似体系复合氧化物的合成,把A₂B₂O₇中A位元素由钇换为镧,B位元素保持不变,通过设计的简单的水热法,在较低的温度下合成具有烧绿石结构的La₂Sn₂O₇纳米球,证明了设计的水热方法适用于相似体系的复合氧化物的合成。并观察到较大的La₂Sn₂O₇纳米球是由更小的结晶良好的纳米片自组装而成。发现其具有与纳米Y₂Sn₂O₇颗粒相似的光催化性质。4.为了合成光催化能力更高的层状复合氧化物,把A₂B₂O₇中B位元素由锡换为钛,A位元素保持不变,通过设计的简单的水热法合成了具有较为规则的长方形钙钛矿结构层状化合物La₂Ti₂O₇纳米片。通过对样品比表面积的测量,发现样品具有较大的比表面积;通过对其微观结构进行分析,发现更多还原

【Abstract】 The compounds with the general formula of A₂B₂O₇ include many kinds of composite oxides with different structure. Because they possess many excellent physical properties,they have become the important investigation object in the nanomaterials field. At the same time;they were the important application materials in actual life. However,these compounds were generally synthesized through the traditional high temperature solid state reaction,which is not only wasting energy,polluting environment,but is easily induce impurity and the particle size is large.The main points of this thesis rest with exploring novel hydrothermal methods to synthesize functional composite oxides nanomaterials , and studying the photocatalytic properity of the products,and investigating the effect of particle size,mopholougy and the structure on the propertiy. The main results achieved are summed up as following:1. A hydrothermal process had been designed and successly applied in the synthesis of many composite oxides nanomaterials with the general formula of A₂B₂O₇ （A=Y,La,Bi;B=Sn,Ti）.2. Nanosized Y₂Sn₂O₇ powder photocatalysts with different particle sizes were synthesized through the low temperature hydrothermal method by using different organic agents （polymethyl methacrylate: PMMA , cetyltrimethyl ammonium bromide: CTAB or ethylene diamine tetraacetic acid: EDTA）. A formation mechanism of the Y₂Sn₂O₇ nanoparticles with different sizes in the presence of organic agents was proposed. The diffuse reflection spectrum shows that with the decrease of sample particle size,the absorbance edges of samples move to long wavelength,that is to say,the red shift occurs. The surface areas of samples indicate that different kinds of organic agents result in the difference in the particle sizes,and the surface areas of the samples. The surface areas varied with the heat treatment temperature. The photo catalytic experiments showed that the更多还原