Nano-phase separation and the effect of SnO addition in TiO2-precipitated glass–ceramics

We have investigated the nano-structure of TiO2-precipitated CaO-B2O3-Bi2O3-Al2O3-TiO2 (CaBBAT) glass–ceramics, and discussed the effect of the addition of SnO. 119Sn Mössbauer spectra of the Sn-doped glass suggest that most of the SnO was oxidized during melting. Selective crystallization of TiO2 occurred independently of SnO addition in the homogeneous glass. However, EDX analysis of the glass–ceramics revealed that the Ti cation is partially localized and that the addition of SnO promotes the nano-phase separation. It can be concluded, therefore, that the addition of SnO influenced the formation of secondary particles of TiO2 nano-crystallites and thereby improved the photocatalytic activity.