Photocatalytic decomposition of gaseous formaldehyde usingTiO2,SiO2−TiO2and Pt−TiO2

Abstract

In this study, in order to improve the photocatalytic decomposition activities of formaldehyde,TiO2catalyst modified withSiO2substitution and metal (Pt, Cu and Fe) impregnation, were tested. In case ofTiO2substituted bySiO2, the optimal catalytic activity was found at the mole ration of 2 : 8. Among the metal impregnatedTiO2, the Pt impregnatedTiO2showed the best activity even better than that of P-25 which is widely used in commercial application. However, Cu and Fe impregnatedTiO2showed the reverse effect. In the case ofSiO2substitutedTiO2the observed values of photoluminescence spectroscopy were quite proportional to the photocatalytic activities depending upon the mole ratio ofSiO2toTiO2. However, for the samples of metal impregnatedTiO2, the reverse relationships were found. In UV-visible spectra for metal impregatedTiO2, the transmittance value was reduced depending upon the loading of metals. The enhanced photocatalytic activity for high metal loading onTiO2might be associated with the high concentration of excited electron that was monitored through UV-visible spectra.