Photocatalytic decomposition of gaseous formaldehyde using TiO₂, SiO₂‐TiO₂ and Pt‐TiO₂

Abstract

In this study, in order to improve the photocatalytic decomposition activities of formaldehyde, TiO 2 catalyst modified with SiO 2 substitution and metal (Pt, Cu and Fe) impregnation, were tested. In case of TiO 2 substituted by SiO 2 , the optimal catalytic activity was found at the mole ration of 2: 8. Among the metal impregnated TiO 2 , the Pt impregnated TiO 2 showed the best activity even better than that of P‐25 which is widely used in commercial application. However, Cu and Fe impregnated TiO 2 showed the reverse effect. In the case of SiO 2 substituted TiO 2 the observed values of photoluminescence spectroscopy were quite proportional to the photocatalytic activities depending upon the mole ratio of SiO 2 to TiO 2 . However, for the samples of metal impregnated TiO 2 , the reverse relationships were found. In UV‐visible spectra for metal impregated TiO 2 , the transmittance value was reduced depending upon the loading of metals. The enhanced photocatalytic activity for high metal loading on TiO 2 might be associated with the high concentration of excited electron that was monitored through UV‐visible spectra.