Photoreactivity of TSP: A novel microporous titanosilicate

The photoreactivity of TSP, a microporous titanosilicate with the pharmacosiderite structure consisting of nanoclusters of titania octahedra linked through silicate tetrahedra, has been studied by EPR spectroscopy. UV irradiation of TSP in the presence of O2 produces the EPR signal of holes trapped at oxide ion sites (O−). This is attributed to the scavenging of electrons by O2. The trapped holes in TSP are much more stable than the corresponding species in TiO2. Reaction of O2 with O− to form O3- is also observed. Trapped holes can be seen as well when TSP is irradiated in the presence of adsorbed CO2, which can also act as an electron scavenger.