【作者】 梁家和；

【导师】 李亚栋；

【作者基本信息】 清华大学 ， 化学， 2005， 博士

【摘要】 氧化物是自然界中分布最为广泛的一类无机化合物。由于其独特的物理、化学性质和在众多领域的广泛应用,氧化物在工农业生产以及科学研究占有极其重要的位置。如何发现、合成新型结构的氧化物功能材料,并在合成过程中实现对其晶体结构、尺寸、形貌及维度的调控,进而实现对其物理、化学性质的人工剪裁是当前化学、材料科学要完成的历史使命。湿化学合成方法被证明是完成这一使命的非常重要的途径。本论文通过调控溶剂体系、溶液酸碱度、前驱物和添加剂种类等方式在利用湿化学方法合成二元和三元氧化物低维纳米结构方面进行了有益的探索和研究,获得了一些有意义的结果。二氧化锆(ZrO2)是一种多晶型的二元氧化物,采用不同的湿化学合成方法成功地合成了不同晶型的ZrO2结构:微波辅助化学湿法合成ZrO2纳米颗粒,在PVA的作用下合成介稳四方相二氧化锆(t-ZrO2);超声波辅助化学湿法合成水合二氧化锆(ZrO2·nH2O),并对其结构进行了表征;醇水体系(EWS)水热合成了单分散单斜相二氧化锆(m-ZrO2)纳米颗粒。氧化镍(NiO)是一种单晶型的二元氧化物,通过水热方法首先合成六方相氢氧化镍(h-Ni(OH)2)的纳米棒状结构,然后在加热条件下,使Ni(OH)2纳米棒转化成为立方相氧化镍(c-NiO)纳米环状颗粒。建立了一种简便、普适的水热合成方法制备了系列过渡金属三元氧化物铬酸盐的低维纳米结构。系统深入探讨了溶液的酸碱度(pH)和添加剂(表面活性剂)对于晶体生长中晶型和形貌的影响,这对于湿化学合成中的晶体结构、尺寸和形貌的调控研究具有很高的借鉴价值。对制得的产物的介电、电化学、紫外吸收和荧光性质进行了表征和研究。提供了一种新的低温液相合成非金属三元氧化物硼酸盐的一维纳米结构的方法,比传统固相反应方法的反应温度低近700°C ~900°C,显示了湿化学合成的优势。尤其是在醇酮体系下合成了掺杂二价铕(Eu2+)的硼酸盐荧光粉体,同时在纯水溶剂中合成了掺杂三价铕(Eu3+)的硼酸盐荧光粉体,在紫外灯的照射下,荧光体分别发出蓝紫光和粉红色光。并对掺杂荧光体一维纳米结构的热稳定性和其发光性质进行了测试和表征。更多还原

【Abstract】 Oxide is one type of inorganic compound widely spreading in the nature. Due toits unique chemical and physical properties and broad applications in many fields,oxide is of great importance to the proceedings of industry and agriculture andresearches of science. A history mission in the current chemistry and materialsscience is how to find and produce functional oxide materials with new structures,and how to precisely control the crystal structures, sizes, morphologies anddimensionalities, further to achieve the tailoring of physical/chemical properties ofthe materials. Wet chemistry method proved to be a great way to reach the goal. Inthis dissertation, low-dimensional nanostructures of binary and ternary oxides aresuccessfully synthesized via wet chemistry by modulating the parameters such assolvent, pH, precursor and additive.Polymorphous zirconia (ZrO2) is synthesized via wet chemistry method:Polymer-stabilized metastable tetragonal (t-ZrO2) nanopowders have been preparedby microwave-assisted heating in an aqueous solution containing PVA;hydratedzirconia (ZrO2·H2O) nanopowders have been synthesized via sonochemical method;monodispersed monoclinic zirconia (m-ZrO2) nanoparticles have been produced viahydrothermal method in ethanol-water system. Nickel oxide (NiO) nanorings havebeen synthesized by the phase transition from hexagonal Ni(OH)2 to cubic NiO viahydrothermal-annealed method.A facile general synthesis route to a family of chromate one-dimensionalnanostructures has been established. The effects of pH and surfactant on phase andmorphology formation in the crystal growth have been systematically investigated.The physical properties, such as dielectric, electrochemical, UV-Vis absorbance, andphotoluminescent properties, of the as-synthesized chromate nanocrystals have alsobeen studied.One-dimensional nanostructures of metal borate are successfully synthesized viasolution-phase method at low temperature, approximately 700℃~900℃ less thanthat in conventional solid-state reaction. Eu2+ and Eu3+ doped borate fluorophors havebeen selectively synthesized in the ethanol-acetone solvent and water solvent,respectively. The fluorophor, exposed to UV, emits blue-violet and pink lightrespectively. The thermal stability and PL properties have also been investigated.更多还原