【作者】 王淑涛；

【导师】 张祖德；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2006， 博士

【摘要】 本论文旨在探索钼的一系列非金属材料及其特殊纳米结构的合成及表征。在广泛深入的文献调研基础之上，通过水热或醇热的液相化学合成路线，成功地合成了MoO₃、MoO₂及MoN，用各种分析手段对产物进行了表征，并对MoO₃的光催化性质进行了研究。论文内容简要归纳如下： 1．通过水热法成功合成了直径50～900nm，长11μm的α—MoO₃单晶纳米带，在阳离子表面活性剂CTAB的辅助下，成功实现了纳米带到球形或花状结构的组装，并对组装过程的可能机理进行了详细讨论，说明反应温度、CTAB浓度及试剂添加顺序对组装过程都有显著影响。在阳光照射下，该纳米带对亚甲基兰的可见光催化降解具有催化活性，为开发利用纳米带提出了新的途径，有望应用于环境污染治理。 2．通过前驱物模板辅助的还原蚀刻法制备了直径约80～225nm，长度约2μm的1D多孔MoO₂及直径约260～500nm的球状多孔MoO₂。前驱物、还原剂、capping试剂、反应时间等对产物的形貌及其中Mo的氧化态都有显著影响。该反应条件温和，产物为亚稳的非晶MoO₂。该非晶需要在N₂气氛中煅烧才能转化为晶体。产物中同时得到多孔纳米纤维及纳米球，选择生长多孔纳米纤维或纳米球尚未实现。 3．改进Pechini法，以CA和EG作为辅助试剂，通过醇热还原反应制备了非晶及结晶状态的MoO₂微米球。通过调节溶液组成及调节pH实现了对产物形貌和结晶程度的控制。但微米球的单分散性还有待改进。此外，以CA作配体，EG作酯化剂，成功实现了MoO₂纳米颗粒到微米球的组装。 4．氨解多硫化物前驱物，成功制备了毫米级的实心及管状MoN纤维。前驱物本身起到一个类似碳纳米管的模板作用，其形貌及尺寸与产物极为相似。以反应物自身作为模板制备大尺寸的3D氮化产物，简化了通常硬模板法中模板去除及纯化的步骤。对不同温度下制备的前驱物进行了表征，并在氧化物—硫化物局部规整转化模型的基础上提出了硫化物—氮化物局部规整转化模型。该模型有望扩展到在不同尺度范围内的更多相似体系中。更多还原

【Abstract】 The goal of this dissertation is to explore the synthesis and characterization of some molybdenum based inorganic materials and their related nanostructures. Based on a wide and in-depth literature investigation, the author successfully synthesized MoO₃, MoO₂ and MoN via hydrothermal or ethanothermal route and investigated the catalytic property of MoO₃. The details are summarized as follows:1. Single crystalline nanobelts or nanoribbons and spherical or flowerlike hierarchical structures of α-MoO₃ were obtained through homogeneous precipitation and subsequent hydrothermal treatment. It has been found that temperature, concentration of cationic surfactant cetyltrimethylammonium bromide （CTAB）, and the addition order of reactants are the three critical factors for the assembly of nanobelts in the current process.2. Synthesis of porous molybdenum dioxide MoO₂ with one-dimensional （1D） and spherical morphology in aqueous solutions has been investigated systematically by varying the precursors and the reducing agents as well as the reaction temperature and durations. The average diameter of the MoO₂ nanofibers is about 80-225 nm, and the length is up to 2 μm. The average diameter of the MoO₂ nanospheres is about 260-500 nm. The reduction of precursor yields metastable amorphous oxide of lower-valence molybdenum, which will crystallize around 400°C after calcinations. It has been found that the 1D morphology of the trioxide precursor and the hydrogen bonds associated with organic acid play a decisive role in determining the size and shape of the final product. The current method provides an approach to fabricate porous structure from a shaped template through redox etching process at ambient temperatures.3. The Pechini process was modified to provide an ethanothermal reduction route to molybdenum dioxide microspheres at ambient temperature. The effects of citric acid （CA）, ethylene glycol （EG）, and H₂SO₄ environment on the formation of molybdenum oxide （MoO₂） were studied. Nanoparticles with the average diameter更多还原