Nano structurizing and new oxidation catalyst development of perovskite compound oxide by structuralo rganics assistance

具有纳米结构的固体材料因其在催化活性中心附近独特的反应场而具有诱人的催化性能，有望成为潜在的化学反应催化剂。此外，催化组分的三维组织对于固体催化剂，特别是对于经常需要进行各种多步骤催化反应的多功能催化剂来说，是非常重要的。因此，采用溶胶-凝胶法、水热法、溶剂热法、有机模板法等无机软合成方法制备纳米材料显得尤为重要。本研究采用以下三种纳米结构方法制备复合金属氧化物催化剂：(A)有机球形模板法制备三维有序大孔材料，(B)碳纳米纤维模板法制备纳米管状材料，(C)制备I-…首先，制备了具有三维有序结构的多晶尖晶石和钙钛矿型大孔材料。该材料采用胶体晶体模板法制备，具有极高的成品率和高度的均匀性。这些微晶被发现构成连接四面体和正方形棱柱顶点的支柱。在氧化物纳米管的合成中，模板与氧化物的均匀包覆是最重要的过程。本研究表明，通过前驱体在碳纳米纤维(CNF)模板表面的吸附和水解以及模板的氧化去除，可以合成各种氧化物纳米管。可以合成各种反映碳纳米纤维形状的氧化物纳米管，如厚的、薄的和螺旋状的纳米管。此外，我们还结合CVD工艺和CNFS模板法，展示了纳米纤维金属氧化物在宏观结构材料上的固定化。碳纳米纤维的显著特征之一是通过CVD过程在各种衬底上形成碳纳米纤维。利用碳纳米纤维的这一特性，我们尝试了将纳米纤维金属氧化物固定在二氧化硅纤维等宏观结构材料上。少量催化碳纳米纤维生长的镍颗粒附着在石英纤维上，然后甲烷与石英纤维负载的镍接触(即CVD过程)，导致了碳纳米纤维在石英纤维上的生长。将固定化碳纳米纤维作为模板用于金属氧化物纳米管/纳米纤维的合成。各种纳米结构材料在有机氧化反应中都表现出各自独特的催化性能。较少

Solid-state materials with nano-scale structures are expected to be potential catalysts for chemical reactions because the materials would have attractive catalytic properties due to their unique reaction field around catalytic active sites. In addition, three-dimensional organization of catalytic components is highly important for solid-state catalysts, particularly for a multi-functional one which is often necessary for various multi-steps catalytic reactions. Therefore, it appeared that nano-scale materials structuring using inorganic soft syntheses like sol-gel method, hydrothermal method, solvothermal method, organic template method, and so on, thought to be significantly important. In this research, the following three types of nano-structuring methods for complex metal oxide catalysts; (a) organic sphere template method for three-dimensionally ordered macroporous materials preparation, (b) carbon nano-fiber template method for nano-tube shaped materials, and (c) preparation of i … More mmobilized nano-fibrous complex metal oxides on ceramic fibers were developed.First, three-dimensionally ordered macroporous materials of polycrystalline spinel-and perovskite-type materials were prepared. The materials were fabricated using colloidal crystal template method in extremely high yield and in high uniformity. The crystallites were found to construct struts connecting tetrahedral and square prism vertexes. In the synthesis of oxide nanotubes, uniform coating of templates with oxide was most important process. The present study demonstrated that various oxide nanotubes could be synthesized by the adsorption and hydrolysis of precursors on the surface of carbon nanofiber (CNFs) templates and by the oxidative removal of templates. A variety of oxide nanotubes such as thick, thin, and helical nanotubes reflecting the shapes of carbon nanofibers could be synthesized. In addition, we demonstrated the immobilization of nano-fibrous metal oxides on macro-structured materials, combining CVD process and CNFs template method. One of the notable features of CNFs is the formation on the various substrates through CVD process. Using this feature of CNFs, we attempted the immobilization of nano-fibrous metal oxide on the macrostructure materials like silica fibers. A small amount of Ni particles which catalyze CNF growth are attached on the silica fibers, followed by the contact of methane over silica fiber-supported Ni (i. e., CVD process) resulting in the growth of CNFs immobilized on silica fibers. The immobilized CNFs are used as templates for metal oxide nano-tubes/nano-fibers synthesis. All the nano-structured materials showed their own characteristic catalytic performance in organic oxidation. Less