| Fabrication of micro/nanoscale inorganic materials with special morphology and size has been a focus in areas of materials science. The rational design and synthesis of advanced micro/nanostructured materials with controllable morphology and diverse compositions has attracted tremendous interests in the fields of nanoscience and nanotechnology. Nickel hydroxide has been used as the active material of the positive electrode in rechargeable batteries due to its excellent electrochemistry performance. Aluminum oxide hydroxide and alumina have drawn much attention because of their potential application in the fields of ceramics, catalyst supports, abrasives, adsorbents and optical devices.This paper focused on controlled synthesis of micro/nanoscale inorganic materials (Ni(OH)2, NiO, AlOOH and Al2O3) with various morphologies by solution-phase method. In addition, formation mechanism and properties of as-obtained micro/nanostructures were also investigated. The detailed information of the paper is listed as follows:1. Controlled synthesis of ultralong single-crystalline a-Ni(OH)2 nanbelts and corresponding porous NiO nanobeltsAll of these current 1D micro/nanostructures were prepared under the assistance of templates and were all polycrystalline character. Ultralong single-crystalline a-Ni(OH)2 nanobelts were synthesized through hydrothermal method using NiSO4·6H2O as nickel source and ammonia as basic source. The diameter of the nanobelts (100 nm) did not show significant change during the whole process based on the experiment results. Therefore, it is believed that nucleation-aggregation-dissolution-seed-directed growth mechanism should be the possible formation mechanism for the ultralong single-crystallineα-Ni(OH)2 nanbelts. Furthermore, short porous NiO nanobelts were obtained by annealing the as-prepared ultralong Ni(OH)2 nanobelts. 2. Fabrication of a-Ni(OH)2 microflowers in the mixed solventa-Ni(OH)2 microflowers were successfully fabricated in the mixed solvents of methanol and water, which Ni(NO3)2·6H2O was selected as nickel source and ethanolamine as OH- provider. On the basis of the experiment results, eachα-Ni(OH)2 microflower is composed of dozens of porous petals. The content of water could considerably influence the morphology and phase of the finally products. When other alkali media, such as sodium hydroxide and ammonia, were employed as reactants instead of ethanolamine, no flowerlike structures could be obtained, which indicates that the formation of flowerlike microstructures may be related to the special structure and basic environment of ethanolamine.3. Synthesis of high dispersed y-AlOOH andγ-Al2O3 architectures in the mixed solvents of DMF and water with the assistance of PVPWe have synthesized high dispersed y-AlOOH architectures in the mixed solvents of DMF and water with the assistance of PVP (ellipsoidal flowerlike, rotor-like, carambola-like, and leaf-like). The volume ratio of DMF to water, the content of AICl3, reaction temperature and reaction time play important roles in the formation of y-AlOOH architectures. In the same way, we studied the formation mechanism through the evolution process observation from TEM images at different times, and found it was a one-step self-assembly mechanism (0D-3D). In addition, high dispersedγ-Al2O3 architectures were synthesized by the thermal decomposition ofγ-AlOOH precursor. The morphology of y-AlOOH could be preserved after heat treatment and a lot of pores left due to the release of gases.4. Preparation of 3D y-AlOOH architectures assembled by nanosheets3D y-AlOOH architectures assembled by nanosheets were successfully synthesized in the mixture of deinonized water and dimethyl sulfoxide (DMSO) without templates, surfactants and polymers. On basis of the experiment results, it is expected that these novel 3D y-AlOOH microsturctures may be a promising candidate as ceramics, adsorbents, catalysts or optical devices due to its loose texture, large specific surface area and unique optical property.
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