【作者】 梁慧；

【导师】 杨延钊；

【作者基本信息】 山东大学 ， 无机化学， 2010， 博士

【摘要】 具有特殊形貌、尺寸的无机微纳材料的构筑是当前材料领域研究的热点；探索发展微纳材料设计与合成的新途径、新方法,从而实现对微纳材料的尺寸大小、粒径分布和形貌的控制则始终是纳米材料研究领域中的一个重要课题。氢氧化镍由于具有良好的电化学性能,而被用作电池正极材料的活性物质。而AlOOH和Al203因其在陶瓷、催化剂载体、研磨剂、吸附剂以及光学器件中的潜在应用价值也受到广泛关注。本论文主要工作是利用液相合成方法成功地制备了多种形貌、尺寸的镍、铝化合物微纳材料；并对其形成机理以及性质表征等方面进行了系统的研究。1.单晶α-Ni(OH)2超长纳米带的控制合成及多孔NiO纳米带的制备目前制备一维微纳结构多是借助于模板,且产物多为多晶结构。本文以硫酸镍为镍源,氨水作为碱源,通过简单的水热反应成功地制备了单晶α-Ni(OH)2超长纳米带。结果表明,自纳米带出现直至最终超长纳米带成形,其宽度一直保持在100 nm左右,因此,我们提出结晶-聚集-溶解-“晶种”导向是超长纳米带形成的机理。且进一步以制得的单晶α-Ni(OH)2超长纳米带为前体,通过简单的煅烧,得到了具有多孔结构的NiO纳米短带。2.甲醇-水体系中制备α-Ni(OH)2微米级花状结构以硝酸镍为镍源,乙醇胺为碱源,在甲醇-水体系中成功地合成了α-Ni(OH)2微米级花状结构。结果表明,该结构由花瓣状的多孔片组成。且溶剂中水的量对产物的形貌和物相都有很大的影响。改变碱源(如NaOH,氨水)则不能得到花状结构,因此,我们推断,乙醇胺的结构和其自身的水解性质对形成花状结构的产物有重要的作用。3.PVP辅助、DMF-水混合溶剂下制备高分散性的γ-AlOOH颗粒和y-Al203颗粒在PVP的辅助下,于DMF-水混合溶剂中制备出高分散性的γ-AlOOH结构(椭花球、转子、杨桃状和叶片状)。通过控制溶剂中DMF与水的比例、反应物AlCl3的量、反应温度和反应时间,可以得到不同形貌的γ-AlOOH微纳结构。借助不同时间段的TEM图像进行分析,发现制备出的高分散性的γ-AlOOH结构是由极小的纳米颗粒一步组装而成形的(0D-3D)。经过简单的灼烧过程,同样得到了分散性良好的γ-Al203结构,其前体的形貌得以完好的保持。γ-Al203结构的表面出现了许多因水分子逸出遗留的孔隙。4.水热法合成纳米片组成的γ-AlOOH三维结构在未使用模板、表面活性剂和聚合物等添加剂的情况下,我们采用简单的水热体系,通过体系中引入二甲基亚砜,合成了由纳米片组成的γ-AlOOH三维结构。该产物具有的疏松结构、较大的比表面积以及较强的发光性质,为γ-AlOOH三维结构的实际应用提供了机会。更多还原

【Abstract】 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.更多还原