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非模板法溶剂热低温热处理制备纳米结构介孔金属氧化物
Template-freee Solvothermal Synthesis of Nanostructured Mesoporous Metal Oxides by Low-temperature Heat-treatment
【作者】 凌宗欣;
【作者基本信息】 南京航空航天大学 , 物理化学, 2010, 硕士
【摘要】 纳米结构介孔金属氧化物因其具有介孔材料和纳米材料独特而优异的物理化学性能,在催化、气敏传感器、电极材料、陶瓷等领域具有广泛的应用前景。本论文丰富和发展了纳米结构介孔金属氧化物的制备方法,非模板法溶剂热低温热处理制备纳米结构介孔金属氧化物是一种具有反应条件简单、产物结晶好、纯度高、绿色合成等特点的方法。本文使用XRD、SEM、TEM、BET的表征方法,较系统地研究了不同实验参数对样品的比表面积、形貌等的影响,取得的研究成果归纳如下:溶剂热-低温热处理法制备纳米结构介孔氧化镁:样品的表征结果表明反应介质的不同对样品的比表面积、形貌有重要影响,醇水体积比1:1得到的氧化镁的比表面积为373.2 m2/g,孔容值0.71 cm3/g,孔径分布2-4 nm,反应介质中蒸馏水的存在有利于样品规则形貌的形成。文中初步探讨了样品内部介孔的形成机理。溶剂热-低温热处理法制备纳米结构介孔氧化镍:SEM、SAED照片表明该样品保留了前驱物的六边形形貌和单晶结构。在所测温度范围内,水热反应温度越高,所得样品的形貌越规则。溶剂热-低温热处理法制备纳米结构介孔氧化铟:反应碱源的不同对样品形貌有重要的影响,这为不使用模板剂获得不同形貌的纳米介孔氧化物奠定了实验基础。
【Abstract】 Because of the unique physical and chemical properties, nano-structured mesoporous metal oxides have broad application in catalysis, gas sensors, electrode materials, ceramics and other fields. This research enriched and developed the preparation methods of the nanostructured mesoporous metal oxides. Template-free solvothermal low-temperature heat treatment method adopted in this paper is a good way with simple reaction conditions, good product crystallization, high purity characteristics and green features. The samples were characterized by XRD, SEM, TEM and N2 adsorption-desorption analysis. A systematic study has been done for the effects of different experimental parameters on specific surface area and morphology of the samples. Research results obtained in this paper are as follows:The preparation of nanostructured mesoporous MgO: N2 adsorption-desorption analysis shows that the different reaction media has an important influence on surface area and morphology of the sample. With the pore size distribution 2-4 nm, the BET surface area and pore volume can reach up to 373.2 m2/g and 0.71 cm3/g when the volume ratio of distilled water to ethanol is 1:1. The reaction medium in the presence of distilled water is conducive to the formation of the regular morphology. We preliminary studied the formation mechanism of mesopores within the samples.The preparation of nanostructured mesoporous NiO: The SEM and SAED results show that the sample inherits the hexagonal morphology and single-crystal structure of the precursor. In the measured temperature range the morphology of the samples is more regular as the hydrothermal reaction temperature becomes higher.The preparation of nanostructured mesoporous In2O3: Without adding the templates, the difference of the alkali source has an important influence on the morphology of the product. This conclusion provided the experimental basis to to obtain the different morphology of products without using the templates.
【Key words】 Solvothermal; Low-temperature heat treatment; Nanostructure; Mesopore; Metal oxides;