Controlled Synthesis And Aseembly Of Three-Dimensional Hierarchical Micro/Nanostructures Of Solid Solution (NH₄,Na)₃AlF₆ And CuS

We synthesized a series of hierarchical self-assembled architectures that included various architectures of (NH4,Na)3AlF6 solid solution (octahedron, hexapod, flower, hole octahedron, and open truncated octahedron) and hierarchical structured copper sulfide(flower-like spheres and self-assembled chains) by a facile solution route and a facile microwave irradiation method, respectively. The related research background and details were introduced as follows:1. Most natural minerals are solid solutions that comprise two or more end—members. The solid solution is closely related to chemical reactions that taken place in the earth crust. Therefore, we inevitably investigate the property of solid solution in order to well study and reconstruct the form conditions for minerals, rocks or ore deposits. Meanwhile, solid solution materials are of specific application in various fields that involve thermoelectricity, semiconductor, storage, glass–ceramics, luminescent and superconductive materials. Therefore, systemic investigation the solid solution synthesis, shape evolution, growth mechanism, not only provide novel ideas in exploring geological evolution but also provide novel ideas for designing and fabricating high-performance and intelligence materials in future. In recent years, although many efforts have been devoted to preparing various structured solid solutions, the complex shapes of the solid solution and the relevant research on solid solution-morphology effected by the capping agent and dissolved ions were rarely reported. Because of the importance of the shapes and textures of materials in determining their widely varying properties, it is significant to study the relationship among shapes, textures, and the components of solid solution. Although some researchers have tried to elucidate the growth mechanism of these crystals, the well understanding for the final crystal architectures constructed by the building blocks is still limited. If the growth mechanism and process can be well understood, there is a better chance to prepare inorganic crystals with expected morphology at high yields. Consequently, understanding the growth driving force and the shape-guiding process of microcrystals is technologically important in the shape- and size-controlled synthesis of microcrystals, and realizing the formation of various crystal geometries and the conversion between them will make it possible to program the system to yield building blocks of a desired shape and/or size. In the chapter, In present work, by use of a facile route, we synthesized a series of (NH4,Na)3AlF6 solid solution architectures, and the morphological conversion processes were also studied in detail. On the basis of our experimental results, a plausible microcrystal-stack-based growth mechanism is proposed for the formation of the various hierarchical architectures.2. The synthesis of inorganic materials with well-defined morphologies based on the construction of nanounits (nanowires, nanosheets, nanoneedles, nanobelts or nanotubes) has gained considerable attention over the past a few years because of their importance in basic scientific research and potential technological applications. Hierarchical inorganic micro-/nanostructures, constructed by using various nanomaterials as building blocks, may provide an effective pathway towards the systematic study of structure-property relationships and improve the physical and chemical properties of the nanoscale materials with simple configurations. In the chapter, In the present work, using microwave irradiation and the deionized water as solvent, we have successfully synthesized a variety of copper sulfide architectures for the first time, including hierarchical flower-like spheres, hierarchical chains consisting of the flower-like spheres. Such microwave-assisted fast synthetic strategy may potentially be applicable to the fabrication of other metal chalcogenides with assembled or hierarchical architectures. The influences of the EDTA, concentrations of reactants, microwave power, and reaction time on final morphology of the products were systematically investigated. On the basis of our experimental results, a phenomenological elucidation of the mechanism for the growth of the CuS architectures have been presented.