Process for Preparing Silica/Titania Photocatalyst by the Sol-Gel Method

본 발명은 휘발성 난분해 유기물질의 분해에 대해 높은 광활성을 나타내는 실리카/티타니아 광촉매의 솔-젤법을 이용한 제조방법에 관한 것이다. 본 발명에서는 휘발성 난물질의 분해에 대해 광활성을 나타내는 실리카/티타니아 광촉매를 티타니아의 열안정성을 증가시켜주면서 광여기된 전자들의 촉매표면으로의 확산을 돕기 위해, 아나타제 티타니아 입자내에 무정형의 실리카(SiO2)가 분산되어 있는 형태로 제조하였다. 본 발명에 의해 제조된 실리카/티타니아 광촉매는 트리클로로에틸렌(trichloroethylene; TCE)에 대한 분해능이 기존 광촉매의 기준으로 삼고 있는 데구사P25(DegussaP25)보다 높은 활성을 보이므로, 본 발명의 실리카/티타니아 광촉매는 트리클로로에틸렌과 같은 휘발성 난분해 유기물질 등의 처리에 유용하게 쓰일 수 있을 것으로 기대된다

졸-겔법과 기상법으로 제조한 티타늄계 혼합산화물의 광촉매 특성

학위논문(박사) - 한국과학기술원 : 화학공학과, 2001.2, [ xvii, 231 p. ]Titanium based photocatalyst was prepared by the sol-gel technique and the gas-phase reaction. The photoactivity of prepared photocatalysts was investigated by the decomposition of trichloroethylene as a model reaction. X-ray diffraction, BET, SEM or TEM photographs, FT-IR, UV/visible absorption, ESR, and photoluminescence(PL) spectroscopy were used to characterize all prepared catalysts. It was tried to determine the priority in parameters affecting the photoactivity of titanium based photocatalyst. For nanophase $TiO_2$ prepared by the sol-gel method, it was found that the heat treatment at high temperature without forming rutile phase is a key to the high photocatalytic activity due to the increase of crystallinity and the reduction of bulk defects. From the analysis of ESR and PL spectra, it was clear that the surface active site like $O^-$ is produced and leads the enhancement of photoactivity with increasing the calcination temperature. The crystallite size of titania particle was controlled at a fixed particle size and surface area by the spray pyrolysis. The photoactivity of non-porous titania particles increased monotonically with increasing the crystallite size. In further investigation on the photoactivity of nanometer size titania prepared by the gas-phase pyrolysis of titanium-tetra-isopropoxide, it was confirmed that the crystallinity is more important than the surface area to enhance the photoactivity for TCE decomposition regardless of the preparation method. The photoactivity of nano-size titania prepared by the gas-phase oxidation of $TiCl_4$ is proportional to the relative density of surface OH groups regardless of the content of rutile phase. How much surface OH groups exist on the surface was the primary factor for determining the photoactivity of nano-size titania particles. It was also found that the direct preparation of anatase phase of large crystallite size without any further post heat treatment is crucible to get a high photoacti...한국과학기술원 : 화학공학과