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机构地区:[1]华南理工大学化学与化工学院,广州510640
出 处:《材料导报(纳米与新材料专辑)》2009年第1期142-147,共6页
基 金:国家自然科学基金(20573038)
摘 要:采用强碱性水热处理法分别控制第一次水热反应为160℃和200℃,制备出一维纳米管和纳米棒2种形貌的产物,将其作为第二次水热反应的前驱体,考察了第二次水热体系中pH值和温度对TiO2纳米材料的晶相组成及其微观形貌的影响;采用XRD、TEM以及HRTEM对样品进行了分析。结果表明,当以纳米管为前驱体时,除在pH=0的体系中得到了以金红石相为主的单晶纳米棒外,在pH值为2、4和7的条件下均得到了单晶纯锐钛矿相TiO2纳米颗粒。当以纳米棒为前驱体时,在pH=0的体系中得到了金红石相与板钛矿相共存的纳米棒和纳米颗粒混合产物;在pH值为2、4和7的条件下均得到了纯锐钛矿相TiO2纳米棒;当二次水热温度低于180℃时,前驱体没有转化完全,所得产物为前驱体与锐钛矿相Ti02共存的纳米棒;当水热温度为180℃和210℃时,产物为纯锐钛矿相纳米棒。The transformation of the titanate one-dimensional nanomaterials produced by the first hydrothermal treatment in a strong alkaline medium to TiO2 nanomaterials by the second hydrothermal reaction is studied. The titanate nanotubes and nanorods as the precursors for the second hydrothermal reaction are prepared by setting the first hydrothermal temperature at 160℃ and 200℃,respectively. The effects of the pH value and the temperature of the second hydrothermal system on the phase composition and morphologies of TiO2 nanomaterials are investigated with the aid of the characterization by XRD, TEM and HRTEM. It is shown that when the titanate nantubes obtained at 160℃ of the first hydrothermal reaction are used as the precursor, except the single-crystalline nanorods with rutile in majority are obtained under the condition of pH = 0, single-crystalline anatase nanoparticles are produced under the condition of pH= 2,4 and 7, respectively. When the titanate nanorods obtained at 200℃ of the first hydrothermal reaction are used as the precursor, the mixture of nanopartieles and nanorods with the phase composition of rutile and brookite coexisting are obtained under the condition of pH=0; the anatase nanorods are produced under the condition of pH = 2,4 and 7; when the second hydrothermal temperature is below 180℃, the titanate precursors have not completely been transformed to TiO2 ; when the second hydrothermal temperature is 180℃ and 200℃,the anatase nanorods are obtained.
分 类 号:TB383[一般工业技术—材料科学与工程] TQ424.25[化学工程]
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