Evaluation of photocatalytic activity of transparent anatase nanocrystals-dispersed silica films prepared by the sol-gel process with hot water reatment

摘要

Anatase nanocrystals were precipitated mainly at the surface of the silica-titania gel films with hot water treatment,whereas the addition of poly(ethylene glycol) (PEG) in the films led tothe dispersion of anatase nanocrystals in the whole of the films after the treatment.Both films withand without PEG showed high photocatalytic activities for acetaldehyde,NO_x and stearic acid in the gas-solid system,and for methylene blue and potassium iodide in the liquid-solid sysem. The addition of PEG improved the photocatalytic activities of the resultant films due to the smaller anatase crystallites and the porous film structure. The residualsilica under-layer of the superficially anatase-precipitated films is expectedto act as a protective one for an organic polymer substrate againt the photocatlaytic degadation.