| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 봄 (04/14 ~ 04/15, 전경련회관) |
| 권호 | 30권 1호, p.407 |
| 발표분야 | 기능성 고분자 |
| 제목 | Preparation of Titania Complex by Sol-Gel Process and their Photocatalytic Activities under Visible Light Irradiation |
| 초록 | In recent years, titania has been widely studied for its wide application in photocatalysis, solar cells and hydrogen production because of its no toxicity, stability in aqueous solution, and no photocorrosion under bandgap illumination. However, titania is a wide bandgap semiconductor (3.03 eV for rutile and 3.18eV for anatase) and can only absorb about 5% of sunlight in the ultraviolet region, which can only absorb about 5% of sunlight in the ultraviolet region, which greatly limits its practical applications. Extensive efforts have been made in the development of titanium dioxide photocatalyst that can utilize soloar or indoor light1-3. In this study, titania complex was prepared by sol-gel process with the aim of extending the light absorbtion spectrum toward the visible region. The photocatalytic activity under visible light irradiation was evaluated using methylene blue as a model organic compound. The effect of calcination temperature on the crystal phase and crystallite size was studied. The complex calcined at different temperature was characterized by X-ray diffraction (XRD). And disinfectant activity and deodorization efficiency were investigated under visible light irradiation. Experimental Method Titania complex was prepared by sol-gel process and the molar ratio of titania to methanol is 10%. Tittanium (IV) isopropoxide was used as precursor of titana sol. The major phase of the obtained particles was analyzed by X-ray different (Rigaku D/MAXIIC) using Cu Kα radiation over the 2θ range of 5-80. The crystallite size of the prepared particles was determined from the broadening of the anatase main peak at 2θ=25.3o by the Schrerrer equation. Results and Discussins XRD pattens of titania complex, calcined from 200 to 500℃, can be seen that the diffraction peaks at corresponding angles of anatase phase become much sharper when the temperatures increase form 200 to 500 ℃. The major phase of all the pure TiO2 particle is an anatase structure and a rutile peak was observed above 500 ℃. The crystallite size of powders was determined from the broadening of corresponding diffraction peaks by using Scherrer’s formula D=Kλ/βcosθ, where λ is the wavelength on the X-ray radiation (λ=0.15418 nm), K the Scherer constant (K=0.9), θ the X-ray diffraction peak and β the full-width at half-maximum (FWHM) of (101) plane (in radians), which is corrected for the instrumental broadening prior to calculation of its real particle size broadening. The crystallite crystallite size of the anatase phase of the pure titania increased ca. 7 to 35 nm as the calcinations temperature increased from 200 to 800 ℃. This result indicates that the calcinations improve the crystallinity of the particles and the anatase phase changes into the rutile phase with an increase of calcinations temperature. The effect of particle size on the photocatalytic activity of the titania complex for the oxidative degradation of methylene blue in distilled water under visible light irradiation was investigated. After the adsorption equibrium of methylene blue onto the catalyst was established in the dark, about 30% of the initial concentration of methylene blue is absorbed onto the titania complex. A blank experiment in the absence of irradiation but with titania complex demonstrates that no methylene blue degration occurs. It can be seen that the photocatalytic degradation of methylene blue proceeded on the titania photocatalst under visible light irradiation. After 3 h photodegradation reaction excited by visible light, 95% methylene blue was destroyed on titania complex. The degradation of methylene blue on titania complex under visible light irradiation is attributed to the photosensitization process. References 1. P. Cheng, W. Li, T. Zhou, Y. Jin, M. Gu, 168, 97 (2004) 2. W. Y. Choi, J. Korean Ind. Eng. Chem., 14, 1011 (2003). 3. Y. S. Uh, H. S. Choi, J. S. Lim, and J. H. Kim, Ministry of Science and Technology (1992). |
| 저자 | 공병기, 최창용, 나상권, 나재운 |
| 소속 | 순천대 |
| 키워드 | titania complex; photocatalysis |
