Intercalative route to heterostructured nanohybrid

We have successfully synthesized inorganic-inorganic, organic-inorganic and bio-inorganic nanohybrids by applying a chimie douce intercalation technique systematically to layered titanate, to Bi-based cuprate superconductors, Bi2Sr2Cam-1CumOy (m = 1, 2, and 3; BSCCO), and to layered double hydroxides (LDHs), those which are of high importance in terms of basic understanding of intercalation reactions and also having practical application. The inorganic/inorganic hybrids were synthesized by exfoliation-restacking methods to obtain TiO2-pillared titanate. A novel pillaring procedure using an osmotic swelling had been developed to prepare TiO2-pillared layered titanate with a large surface area, high thermal stability, and enhanced photocatalytic activity. On the other hands, the organic/inorganic hybrids were achieved via intercalative complexation of iodine intercalated BSCOO with an organic salt of Py-CnH2n+1I (Py = pyridine). The high-T-c superconducting intercalate with its remarkable lattice expansion can be applied as a precursor for superconducting colloids when dispersed in an appropriate solvent. We were also able to demonstrate that the biomolecules stabilized in the interlayer space of layered double hydroxides (LDH), bio-inorganic hybrids, retain their chemical and biological integrity. If necessary, LDH, as a reservoir, can be, intentionally removed by dissolving it in an acidic medium or interlayer biomolecules in LDH can be released via ion-exchange reaction in electrolyte. It can, therefore, be concluded that the inorganic LDH can play a role as a good host lattice for gene reservoir or carrier. These intercalative methods will provide remarkable synthetic routes to design new heterogeneous hybrid materials, which have the intrinsic properties starting materials and create synergetic effects by hybridization. (C) 2003 Elsevier Ltd. All rights reserved.