Synthesis of APTMS-Functionalized SiO_2/TiO_2 Transparent Film Using Peroxo Titanic Acid Refluxed Solution for Formaldehyde Removal

摘要

Amine-functionalized SiO_2/TiO_2 photoca-talytic films have been synthesized using the peroxo titanic acid (PTA) approach coupled with the sol-gel dip-coating method. The 3-aminopropyl-trimethoxysilane (APTMS) and methyltrimethoxysilane (MTMOS) were employed as the amine functional groups and silica precursor. The effects of the ratio of APTMS/MTMOS, PTA refluxed time, and pH of prepared sol on the characteristics and the formaldehyde degradation efficiency were investigated. Physicochem-ical properties of prepared photocatalysts were characterized with nitrogen adsorption-desorption isotherm measurement, SEM, X-ray diffraction (XRD), UV-vis spectrophotometer, and Fourier transform infrared (FTIR) spectroscopy. The XRD and FTIR results indicated that the obtained photocatalysts consisted of ～NH_2 groups, SiO_2, and anatase TiO_2. The photo-catalytic films showed high transmittance of 80-90% in the visible light region. The obtained film prepared with the APTMS/MTMOS ratio of 0.03, pH of 1.8, and 10 h of refluxed time possessed high specific surface area (604.0 m~2 g~(-1)) and 85% formaldehyde degradation efficiency. The enhancement of formaldehyde degradation efficiency was observed when increasing the PTA refluxed time. The repeatability of photocatalytic filmrnwas also tested, and the degradation efficiency was 92.0% of initial efficiency after seven cycles.