Toluene Decompositions over Al-W-incorporated Mesoporous Titanosilicates Photocatalysts

Abstract

This study investigated the decomposition activities of toluene on 10 mol% Al-W-incorporated mesoporous titano (15 mol %) silicates. The mesopore sizes observed in the transmission electron microscopy images ranged from 2.0 to 5.0 nm, and the pores were irregular on the addition of 10 mol% Al or W ions, but changed to regular hexagonal forms with the simultaneous additions of Al and W. The X-ray photon spectroscopy results showed a shift of the special peak for Ti2p in Al-incorporated mesoporous titanosilicates to a stronger binding energy compared to those of mesoporous titanosilicates and Al-incorporated mesoporous titanosilicates. Three O1s peaks in the spectra of the Al and W coexisted samples were observed at 530.5 and 531.7, 533, and 533.7eV, which were assigned to Ti-Os in TiO2 and Ti2O3, Si-O in SiO2 and Al-O in Al2O3, respectively. The toluene molecules desorbed at lower temperatures over W-incorporated mesoporous titanosilicates, and the amounts of toluene desorbed were also small; however, Al-incorporated mesoporous titanosilicates adsorbed much more toluene, particular over Al7.5-W2.5-Ti15-Si75. The photocatalytic decomposition of toluene was more enhanced over Al7.5-W2.5-Ti15-Si75 than over Al- or W-incorporated mesoporous titanosilicates only.