open access

https://doi.org/10.14943/doctoral.k11616

https://hdl.handle.net/2115/60378

水-グリセリン系電解液中での陽極酸化によるチタニアナノチューブアレイの合成とその光触媒特性

英語

2014-12-25

Hokkaido University

112

TiO2 has attracted much attention in the last decades owing to its superior positionsas biomaterials, in photocatalytic applications, and in dye-sensitized solar cells(DSSCs). For the photocatalytic application of TiO2, the generation of electron–holepairs and their oxidative nature provide manifold applications, such as decompositionof organic pollutants in water and air. The structure and morphology of TiO2 have aconsiderable influence on the photocatalytic performance of TiO2. Thus, over the pastfew years, considerable progress was made particularly in optimizing the nanoscalemorphology of TiO2.Most recently, a novel 1D nanotube structure, TiO2 nanotube array, has been shownto be highly competitive, and in many cases, favorable to achieve enhancedphotocatalytic performance. The cheapest and most straightforward method that leadsto ordered TiO2 nanotube array is anodization technique. In particular, the anodizationapproach allows an easy control on dimensions of anodized TiO2 nanotube arrays(such as layer thickness, pore diameter, interpore distance). Valuable properties ofTiO2 nanotube array, which include semiconductive behavior, photocatalytic andphotoelectrochemical properties, can be enhanced by controlling its geometry. Inethylene glycol-containing electrolyte, by controlling the anodization conditions,many types of TiO2 nanotubes (e.g., ripples free, double-wall) can be formed.However, detailed investigations about these special structures in glycerol-containingelectrolyte have not been fully performed yet.In this context, the preset thesis focuses on revealing the critical mechanisms andanodization conditions to form TiO2 nanotube arrays with various nanostructures (forexample, double-wall and ripples) in glycerol-based electrolytes. The annealing effecton the morphology, chemical composition and structure of double-wall TiO2 nanotubearray were further investigated by both ex situ and in situ annealing method. For theex situ annealing, “fluoride-rich” layer was confirmed in between the double-wall2nanotubes. For the in situ annealing, oxygen gas can be introduced into the TEMcolumn, the in situ sintering behavior of double-wall TiO2 nanotubes was comparedwith and without oxygen gas at real-time by TEM observation. Furthermore, thephotoctalytic activities of double- and single-wall TiO2 nanotube arrays werecompared, decoration of Pt nanoparticles inside both double- and single-wall TiO2nanotube arrays was also examined to enhance their photocatalytic activities.

2014-12-25

甲第11616号

博士(工学)

(主査) 教授 米澤 徹, 特任教授 大貫 惣明, 准教授 菊地 竜也

工学院（材料科学専攻）

博士論文

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