Optical and electrochemical properties of titania pillared clays

The silicate layers of clay were pillared with TiO₂ sol particles. The sol particles were stabilized between the layers against aggregation on heating up to 500°C, and exhibited a wide optical absorption edge tailing to shorter wavelengths compared with bulk anatase-type TiO₂. This indicates the existence of small TiO₂ sol particles with size quantization effects. The silicate layer used as host matrix was almost transparent in UV-visible region. The TiO₂ sol particles between the silicate layers were electrochemically lithiated, and the pillared clay was used as cathode for a rechargeable lithium cell. Transmission electron micrograph of the section perpendicular to the basal planes showed that the pillared clays have a wide distribution in the interlayer spacing. This wide distribution in interlayer spacings apparently leads to the poor crystallinity and the wide observed pore size distribution of the pillared clays.