Solution-Based Low-Temperature Chemical Synthesis And Characterzation Of Low-Dimensional And Hierarchical Inorganic Nanoscale Materials

In this dissertation, base on the survey of literatures and previous works of our laboratory, new routes were developed to synthesize the low-dimensional and hierarchical inorganic nanoscale materials at low-temperature. Several different novel nanostructures were fabricated. In summary, simple solution-based chemical routes were developed to prepare micrometer-scaled hierarchical tubular structures of CuS assembled by nanoflake-built microspheres, hierarchical tubular structures of ternary copper-metal-sulfide compounds, amorphous carbon nanotube bundles and Y-junction hollow carbon nanotrees, and the mechanisms were fully discussed. The details are summarized as follows.1. We first reported the synthesis of micrometer-scaled hierarchical tubular structures of CuS assembled by nanoflake-built microspheres, and studied the effect of TAA in the formation of metal sulfide nanostructures, which happened in the aqueous CuCl₂-TAA system. An transition in the valence state of Cu from +2 in raw material to +1 in intermediate complex then to +2 in final CuS product were observed and fully studied. The novel hierarchical tubular structures of CuS were fabricated via this process. Base on the comparative experiments, the formation process and influences of reaction conditions were investigated, and the mechanism of growth were discussed and proved in detail. The special optical property and the ultra-high specific surface area of products may have potential applications in optical industry, catalysis industry and hydrogen storage.2. Base on the work of section 1, the Cu₃(TAA)₃Cl3 intermediate prisms were used as self-sacrificed template to the successful synthesis of novel hierarchical tubular structures of CuInS₂. Then we expand the route to fabricate hierarchical tubular structures of many ternary copper-metal-sulfide compounds CuMS (M=IIIA, IVA, VA, VIIIB). The method, which is generally suitable for the synthesis of hierarchical tubular structures of many ternary copper-metal-sulfide compounds with high yield and controllable uniform shapes in mild conditions without surfactant or adding templates, may shed light on the synthesis of nanostructures of different ternary semiconductors, in which the intermediate complexes act as self-sacrificed templates.3. Base on the summary of reported works of synthesis of carbon nanotubes at low temperatures, we developed a new one-pot solution-based route to fabricated uniform amorphous carbon nanotube bundles and novel Y-junction hollow carbon nanotrees. The corresponding growth mechanisms were proposed and discussed in detail, which could explain the formation of the unique nanostructures and the influence of reaction conditions. The low-cost route, which could synthesize the carbon nanostructures with high yield and uniform shapes at low temperature without poisonous reagents or adding templates, may be expanded to the fabrications of other novel carbon nanostructures.