Synthesis of Titania-based Nanostructures and Their Applications
타이타니아를 기반으로 한 나노구조의 합성과 응용
- 자연과학대학 화학부
- Issue Date
- 서울대학교 대학원
- titania; nanoparticle; size control; hollow; yolk@shell; electrochemical property; Li-ion battery
- 학위논문 (박사)-- 서울대학교 대학원 : 화학부, 2015. 2. 이진규.
- Titania (TiO2) nanostructures have been widely researched over the past several decades because of their outstanding properties and applications in various fields, in addition to their abundance and low-cost. In particular, titania nanostructures have been used for energy generation in solar-cells and energy storage in batteries.
In this thesis, three simple sol-gel synthetic methods for the preparations of titania of various sizes are reported. Spherical titania nanoparticles with sizes in the range of 60-300 nm could be obtained by changing the amount of reactants. Their size-dependent electrochemical properties are tested using Li-ion battery. Furthermore, simple preparation of hollow titania is also possible by using the soft-template method. Using this method, hollow (Sn,Ti) oxide and an iron oxide@titania yolk@shell structure could be obtained. Furthermore, their electrochemical properties are tested.
Chapter 1 briefly describes the research background on titania nanostructures, including their synthesis methods, surface modifications, and their applications (photo-catalyst, solar-cells, and batteries).
Chapter 2 describes the preparation of spherical titania nanoparticles by using ethylene glycol in acetone solvent to reduce the reactivity of the titania source. The size of obtained titania nanoparticles is approximately between 70 nm and 300 nm
this size variation is obtained by varying the amount of water and the titania source. Reaction conditions including the kind of solvents and chelating agents are investigated.
Chapter 3 describes the preparation of spherical titania nanoparticles by using KCl in ethanol solvent to reduce the reactivity of titania source. The size of titania nanoparticles is controlled by the concentration of KCl and titania source, and the type of solvents. The prepared titania nanoparticles have similar or more powerful photo-catalytic property than that of very small and commercialized titania (P25).
Chapter 4 describes the preparation of spherical titania nanoparticles using a mixed solvent of ethanol and acetonitrile. The size of titania nanoparticles is varied by varying the amount of reactant, especially the water. The size-dependent electrochemical properties of titania are examined by evaluating the Li-ion capacity of about 60 nm, 120 nm, and 280 nm. These properties are related with the surface area measured using both gas- and liquid- based methods.
Chapter 5 describes the preparation of (Sn,Ti) oxide with a hollow structure by the soft-template method under various conditions such as different calcination temperatures and atomic ratio of Sn in the composite oxide. The electrochemical properties of (Sn,Ti) oxide for use as an anode for Li-ion battery are investigated by comparing them with those of hollow titania nanoparticles.
Chapter 6 describes the preparation of an iron oxide@titania yolk@shell structure by the soft-template method. The ratio of the iron oxide core and titania shell could be controlled by changing the amount of the titania source. The electrochemical properties of a yolk@shell anode are compared with those of a just-mixed anode composed of iron oxide and hollow titania nanoparticles, by using Li-ion battery.