【作者】 黄娟茹；

【导师】 谭欣；

【作者基本信息】 天津大学 ， 化学工程， 2012， 博士

【摘要】 本文采用阳极氧化法制备TiO₂纳米管阵列薄膜,首先,通过研究阳极氧化法制备TiO₂纳米管阵列薄膜的影响因素,优化出阳极氧化制备TiO₂纳米管阵列的工艺条件并提出TiO₂纳米管阵列的生长机制;其次,通过控制阳极氧化反应时间制备不同厚度的TiO₂纳米管阵列薄膜,并在FE-SEM、FE-TEM、XRD、XPS等分析基础上,进行了纳米管薄膜的光催化性能研究;接着,结合阳极氧化和不同温度热处理制备出纳米管底开口、管底闭口、管底闭口且管底覆盖着颗粒状的TiO₂致密层三种FS-TNT（Free-Standing TiO₂ nanotube）阵列薄膜,通过FS-SEM、FE-TEM和XRD分析,提出FS-TNT阵列薄膜的制备机理,并通过XPS的分析进行验证;最后,将制备的FS-TNT阵列薄膜与P25 paste薄膜组合制备出FS-P25复合薄膜,并以此复合薄膜为光阳极组装DSSCs进行电池性能的研究,同时也以此该复合薄膜为光催化剂进行光催化活性研究,对其光催化降解结果和反应动力学进行详细的讨论和分析。其具体内容如下:（1）TiO₂纳米管阵列薄膜制备的影响因素和生长机理本文对电解液组成、工作电压、阴极材料、反应时间等影响纳米管阵列薄膜的制备因素进行了较深入的分析和讨论,优化的阳极氧化制备TiO₂纳米管阵列薄膜的条件为:电解液组成为EG（为基准） + 0.5wt%NH4F+3.0vol%H2O,工作电压为60V,阳极和阴极间距为3cm,阴极材料为Pt电极,一次阳极氧化时间为0.5h。并就此提出了阳极氧化制备TiO₂纳米管阵列的生长机制。（2）TiO₂纳米管阵列薄膜的光催化性能研究首先,对阳极氧化制备TiO₂纳米管阵列的管口沉积物进行处理,结果证实经3.0wt%的H2O₂溶液浸渍2h的TiO₂纳米管管口沉积物等杂物几乎完全消失,且纳米管形貌保持良好;接着,研究热处理温度对TiO₂纳米管形貌和结构的影响,发现经高于550℃热处理的TiO₂纳米管,发生严重坍塌,其管状形貌完全丧失,且经XRD分析发现,450℃热处理的TiO₂纳米管的A晶型已经很丰富。最后,对阳极氧化时间为1⁴h和不同温度热处理的TiO₂纳米管进行吸附和光催化活性实验,发现经热处理的纳米管对MB的吸附能力随热处理温度升高而逐渐减弱,光催化降解MB在450℃热处理后,MB的脱除率最高,随后对阳极氧化1h、2h、3h和4h时间并经450℃热处理后的纳米管的吸附和光催化降解Rh.B反应,发现随着氧化时间的延长,对Rh.B的吸附能力增强,氧化时间为2h时光催化脱除Rh.B的效率最高,其值为93.40%,对光催化降解反应动力学分析发现,反应在0⁸0min内基本符合一级反应动力学,当阳极氧化反应2h的TiO₂纳米管的动力学反应常数k=0.03267min-1,反应速率最快。（3）FS-TNT阵列薄膜的制备机理研究采用阳极氧化和热处理联合制备FS-TNT阵列薄膜,在FE-SEM、FE-TEM和XRD分析基础上,分为FS-TNT纳米管底开口、纳米管底闭口和纳米管底闭口且覆盖薄层的TiO₂致密层三种情况讨论FS-TNT阵列薄膜的制备机理,结合阳极氧化制备TiO₂纳米管的生长机理,提出FS-TNT阵列薄膜的制备机理,接着通过对FS-TNT阵列薄膜和下层带基地的TiO₂纳米管进行XPS分析,验证所提出的制备机理。（4）FS-P25复合薄膜基的DSSCs和光催化性能研究在制备FS-TNT阵列薄膜基础上,将FS-TNT阵列薄膜与P25paste薄膜结合制备FS-P25复合薄膜,并以此薄膜为光阳极组装DSSCs进行光电性能研究,发现FS2-P25复合薄膜基电池的光电转化效率最大,其最高值达7.62%,同时将此薄膜应用于光催化降解MB,发现FS2-P25复合薄膜降解MB的效率最高,对其动力学分析发现,反应符合一级动力学反应,且当光催化剂为FS2-P25时,反应的一级动力学常数k=0.01822min^-1为最大,反应速率最快。更多还原

【Abstract】 In the work, TiO₂ nanotube array films were assembled by anodization. Firstly, the fabricating process conditions were optimized and the growth mechanism of TiO₂ nanotube arrays was presented based on effect factors of fabricating TiO₂ nanotube array by anodization. Secondly, different-thick TiO₂ nanotube array films were prepared with controlling the anodic oxidation time, the photocatalytic reaction were analyzed and discussed after the films were characterized via FE-SEM, FE-TEM, XRD and XPS. Thirdly, FS-TNT（free-standing TiO₂ nanotube） array films were prepared by combined three-step anodization and heat treatment, the preparation mechanism of FS-TNT arrays were deeply, detailedly discussed and then presented based on FE-SEM, XRD analysis and the growth mechanism of TiO₂ nanotube arrays, the following mechanism were further confirmed by XPS and EDX. Lastly, the composite films were prepared by assembling FS-TNT and P25 paste film, namely FS-P25, FS-P25 as anode were used to fabricate dye-sensitized solar cells and the cells showed the biggestη% with FS2-P25, and the photocatalytic performances of FS-P25 were evaluated via degrade MB, the photocatalytic kinetics corresponded to first-order kinetics model and the reaction rate is the maximum when FS2-P25 were used for the photocatalyst.（1） Effect factors and growth mechanism of TiO₂ nanotube arrays by anodizationThe effect factors of fabrication TiO₂ nanotube arrays, including electrolyte, work voltage, cathode material and reaction time, were specifically analysed and discussed, then the preparing conditions of TiO₂ nanotube arrays were further optimized, the electrolyte for EG （polyethylene glycol, reference） +0.5wt%NH4F+3.0vol%H2O, work voltage for 60V, the distance between anode and cathode for 3cm, cathode for Pt electrode, the first anodic time for 0.5h. Subsequently, the growth mechanism of TiO₂ nanotube array films were discussed and summarized.（2） The photocatalytic performance of TiO₂ nanotube arrays were researchedThe removing deposit of TiO₂ nanotube mouth by anodization confirmed that these deposits were almost complete obliteration after these nanotubes had been soaked into 3.0wt% H2O₂ solution for 2h, and the morphology structure of nanotubes kept well. The effect of heat treatment on the nanotube morphology structure showed the nanotube antase（A） crystalline of TiO₂ annealed at 450℃had reached to perfect. Followingly, TiO₂ nanotube arrays with 1⁴h anodic time were used in resorption-desorption process and photocatalytic reaction, the results demonstrated that the nanotubes resorption ability for MB increased with heat temperature and the same-length nanotubes annealed at 450℃manifested the optimal performance, especially, the degradation efficiency of Rh.B was up to 93.40% with the nanotubes anodized for 2h, furthermore, the photocatalytic reaction during 0⁸0min corresponded to first-order kinetics model and the maximal reaction rate constant（k=0.03267min-1） was corresponding to the nanotubes with anodic time 2h.（3） The preparing mechanism of FS-TNT array filmsFS-TNT array films were prepared via adopting three-step anodization and heat treatment. FS-TNT array films with nanotube bottom open, nanotube bottom close, nanotube bottom close with thin TiO₂ compact layers were detected via FE-SEM and the preparation mechanisms were discussed and presented based on FE-SEM, FE-TEM, XRD ananlysis and the growth mechanism of TiO₂ nanotube arrays. Then XPS analysis checked the preparation mechanism of FS-TNT array films.（4） The photocatalysis and DSSCs based on FS-P25FS-P25 composite films were assembled based on FS-TNT array films and P25 paste films and then used as photoanode to fabricate DSSCs, and the cells performance showed that DSSCs with FS2-P25 exhibited the biggestη%. Meanwhile, FS-P25 were used to degrade MB and the degradation efficiency were 78.46% corresponding to the biggest first kinetic constant k=0.01822min-1.更多还原