Spray-Dried TiO2(B)-Containing Photocatalytic Glass-Ceramic Nanobeads

Abstract

Glass-ceramic nanospheres of molar composition 0.83 SiO2 · 0.17 TiO2 are produced by the sol-gel spray-drying method followed by controlled heat treatments up to 1200 °C. TiO2(B) and anatase nanocrystals are precipitated in the glassy matrix: the latter phase gradually predominates with increasing ceramization temperature and time, in parallel to an overall increase in crystal sizes. The nanospheres exhibit evident photocatalytic activity under UV-A irradiation, especially at annealing stages involving a comparatively higher amount of TiO2(B) and smaller crystals. The occurrence of TiO2(B) in this simplified binary glass-ceramic material underlines the key role of this phase in the dynamics of crystallizing TiO2-bearing silicate melts.