【作者】 周冰晶；

【导师】 李葵英；

【作者基本信息】 燕山大学 ， 材料学， 2010， 硕士

【摘要】 本文采用溶胶-凝胶法,分别以聚乙二醇(PEG)、十八胺(ODA)、十六烷基三甲基溴化铵(CTAB)为模板剂制备掺镧介孔纳米晶二氧化钛。选择其中一种理想的模板剂(PEG),利用正交设计法优化制备掺镧介孔纳米晶二氧化钛的实验条件;研究复合模板剂对掺镧介孔纳米晶二氧化钛结构与光电性能的影响。利用X射线衍射(XRD)检测样品的晶体结构和晶粒尺寸;通过激光拉曼光谱(Laser Raman)测试对样品的晶格振动模式进行了分析;利用差热-失重分析(DSC-TG)研究前驱物在热处理过程中的相变情况;采用BET方法测定样品的比表面积和孔隙分布;利用透射电子显微镜(TEM)对样品的微观结构、形貌进行表征;根据光声光谱(PAS)、表面光电压谱(SPS)和电场诱导SPS(EFISPS)的检测结果,研究样品的光激发电荷转移跃迁特性。结果表明:镧掺杂可以有效抑制锐钛矿晶粒的生长,在控制锐钛矿向金红石相转变的同时,明显提高二氧化钛样品表面光伏响应强度;以3.0gPEG为模板剂,煅烧温度为500℃时制得样品为蠕虫状介孔结构,与其它模板剂相比,该样品具有较大的比表面积和较强的表面光伏响应;EFISPS检测发现,掺镧介孔纳米晶TiO2样品在波长为375和400 nm处诱导出的表面光伏响应峰分别对应两个性质完全不同的表面态与能带之间电荷转移跃迁;研究证实,光声与表面光伏响应之间存在能量互补关系;实验结果发现,复合模板剂对样品表面光伏特性有明显影响;当PEG与CTAB或与ODA的摩尔比均为1:1时,样品具有较强的表面光伏特性。更多还原

【Abstract】 Lanthanum-doped mesoporous nanometer TiO2 were prepared by sol-gel method with three different template(PEG, CTAB, ODA) respectively . It chose a good template, used orthogonal design method to optimize experimental condition to prepare a better La-doped mesoporous nanometer TiO2 . Finally, it has studied the influence for the composite template agent to the structure and photoelectric property of La-doped mesoporous nanocrystalline TiO2 .We detected crystal structure and grain size of the sample with X-ray diffraction (XRD), analyzed lattice vibration mode of the sample tested by laser Raman spectroscopy (Laser Raman), used differential thermal-gravimetric analysis (DSC-TG) to study precursors changes in the heat treatment process, used specific surface area (BET) method to test ratio surface and void distribution of sample, used transmission electron microscopy (TEM) to characterize the sample’s microstructure and appearance, and studied photo-induced surface charge transfer transition properties according to photo-acoustic spectroscopy (PAS), surface photo-voltage spectroscopy (SPS) and electric field induced surface photo-voltage spectroscopy (EFISPS).It concluded that the La-doped can effectively suppress the growth of anatase Grain, improved the surface photovoltaic effect strength of titanium dioxide during controlling phase transition from anatase to rutile. Taking 3.0g PEG as a template agent, with calcinations temperature to 500℃, it got the sample as worm-like mesoporous structure. Compared to other template agents, it got large specific surface are and strong surface photo-voltage. With the electric field induced surface photo-voltage spectroscopy detected, the surface photovoltaic response peak induced by La-doped mesoporous nano-TiO2 sample during the wavelength of 375 and 400 nano, which is corresponding to two totally different nature of the surface state and charge transfer transitions between the energy band respectiv ely; It existed energy complementary relationship between the photo-acoustic and surface photovoltaic effect; It proved that composite template has significantly effected the sample surface on photovoltaic properties; when the molar ratio reach to 1:1 of the poly - ethylene glycol and acetyl trim-ethyl ammonium bromide or octadecylamine, the sample surface photovoltaic response to be strong.更多还原