【作者】 李丽；

【导师】 陈亚芍；

【作者基本信息】 陕西师范大学 ， 物理化学， 2005， 硕士

【摘要】 随着科学研究的深入和发展,纳米材料引起了人们更广泛的兴趣,并且得到了迅速发展。其中纳米稀土氧化物更是具有传统固体不具有的许多特殊性质和用途,例如二氧化铈和氧化镧等。本文报道了通过配合物简单的热分解得到纳米级二氧化铈和氧化镧的方法,并对所制得的纳米级二氧化铈和氧化镧的性质进行了表征。进一步对这两种稀土氧化物制备过程的中间体配合物,在一定的条件下得到了单晶,并对这两种配合物的性质进行了表征。 （1）纳米级二氧化铈和氧化镧的制备与表征。 以邻硝基苯甲酸和铈的硝酸盐为原料,调节pH值使之产生相应的沉淀,以一定的升温速度和温度煅烧此沉淀,可得到高纯度纳米二氧化铈。讨论了不同焙烧温度、时间和升温速度对纳米二氧化铈粒度和比表面积的影响。通过透射电子显微镜（TEM）和原子力显微镜（AFM）观察,所制得的纳米稀土氧化铈尺寸在3-20nm范围内,并且分散性很好。通过X-射线衍射（XRD）和比表面积测定（BET）的表征也进一步证明了其纳米粒子的尺寸。同时,XRD表征结果显示,此法制备的纳米二氧化铈的高纯度。通过比表面积测定得知,纳米氧化铈的比表面积可以达到74.86m²·g^-1。实验还得出,非离子表面活性剂在纳米级稀土氧化铈制备中起到了非常重要的作用,并对其影响做了讨论。 以邻硝基苯甲酸和镧的硝酸盐为原料,调节pH值使之产生相应的沉淀,以一定的升温速度和温度煅烧此沉淀,可得到纳米氧化镧。通过TEM观察,所制得的纳米稀土氧化镧尺寸在15-40nm范围内,并且分散性很好。XRD表征结果显示,此法制各的纳米氧化镧存在碳化现象。 （2）稀土配合物{Ce[o-C₆H₄（NO₂）（COO）]₃·2DMF}₂ 和{La[o-C₆H₄（NO₂）（COO）]₃·2DMF}₂的制备与表征。 合成了两种新的双核倒反中心的稀土配合物{Ce[o-C₆H₄（NO2）（COO）]₃·2DMF}₂和{La[o-C₆H₄（NO₂）（COO）]₃·2DMF}₂。通过元素分析（EA）和傅立叶红外光谱（FT-IR）对配合物进行了表征,利用热重分析（TGA）研究了配合物的热稳定性,用X射线单晶衍射法（SCXRD）测定了其晶体结构。 铈配合物{Ce[o-C₆H₄（NO₂）（CO₂）]₃·2DMF}₂晶体属三斜晶系,空间群P-1,晶胞参数α=1.18776（17）nm,6=1.24633（18）nm,c=1.29781（18）nm,α=更多还原

【Abstract】 With the development of scientific research, ceria and lanthana in nanometer scale have recently attracted a lot of research interest due to their unique properties and wide range of applications. A wide range of techniques has been developed for the synthesis of ceria and lanthana, including thermal hydrolysis, high-energy ball milling, sol-gel, precipitation, microwave irradiation, semi-batch reactor, and combustion. However, the most of these techniques are spend time due to multi-step syntheses or ageing, consume intensively energy, and being unfriendly for environment. In addition, when the particles with extremely small sizes are desired, the complexity, and sometimes the cost of manufacture, increases further. Here, we report preparation of the nanometer-scale rare earth oxide particles via an easy thermo-decomposition method of complexes. The complexes are derived from the reaction of rare earth nitrate with o-nitro-benzoic acid. The characterization of the complexes and ceria, lanthana powders are presented, respectively.(1) Nanometer-scale CeO2 particles (3-20 nm) have been synthesized by the thermo-decomposition of a new Ce3+ complex taking o-nitro-benzoic acid as ligand. Structure and properties of the Ce3+complexes have been confirmed by XRD, FT-IR and TGA. And the CeO2 powders have been characterized by Raman, XRD, TEM, AFM and BET. The CeO2 powders exhibit a specific surface area of ~74.86 m~2 g~-1. Control over the particle size, surface area, yield, and state of agglomeration could be achieved through variation of the experimental conditions.The nanometer-scale La2O3 particles (15-40 nm) have been synthesized by the thermo-decomposition of a new La3+ complex taking o-nitro-benzoic acid as ligand. Structure and properties of the La3+complexes have been confirmed by XRD, FT-IR and TGA. The La2O3 powders have been characterized by XRD and TEM. And the result of the XRD indicates that some nanometer La2O3 powders can reacted with CO2 in air.(2) {Ce[o-C6H4(NO2)(COO)]3-2DMF}2 and {La[o-C6H4(NO2)(COO)]3-2DMF}2 are synthesized, and the structure of the complex is characterized by FT-IR, ~1H NMR, ~13C NMR, UV, fluorescent emission spectra and X-ray single-crystal diffraction analysis.更多还原