Synthesis and photochemical properties of semiconductor pillared layered compounds

CdS and ZnS mixtures, Fe2O3 and TiO2 pillars were constructed in the interlayer of montmorillonite, layered double hydroxide, H4Nb6O17 and H2Ti4O9 by the intercalation reactions. The thicknesses of the semiconductors incorporated were less than 1 nm and the band gap energies of them were slightly larger than those of normal crystalline ones. The photocatalytic activities of the semiconductors incorporated were superior to those of unsupported ones. The incorporation of semiconductors in the interlayers of semiconducting layered compounds such as H2Ti4O9 and H4Nb6O17 was much more efficient in enhancing the hydrogen production activity than when an insulator such as montmorillonite and layered double hydroxide was used, since the recombination of photo-induced electrons and holes was depressed by the electron transfer from the incorporated semiconductors to the semiconducting host layer. (C) 1999 Elsevier Science Ltd. All rights reserved.