Nanoengineering Route to Two-Dimensional Hybrid Materials

Abstract

We have successfully synthesized inorganic-inorganic, organic-inorganic and bio-inorganic nanohybrids by applying an intercalation technique systematically to layered titanate, molybdenum disulfide (MoS2), Bi-based cuprate superconductors (Bi2Sr2Cam- 1CumOy (m = 1, 2, and 3; BSCCO)), layered double hydroxides (LDHs), and clay minerals, which is of high importance in terms of basic understanding of intercalation reactions and of their practical applications. The inorganic-inorganic systems such as anatase-pillared titanate and CdS-MoS2 hybrids were synthesized by bio-inorganic method. A novel pillaring process using an osmotic swelling was developed to prepare anatase-pillared layered titanate with large surface area, high thermal stability, and enhanced photocatalytic activity. And the intercalation of CdS nanocluster into the two dimensional MoS2 lattice could be also realized by exfoliating and reassembling the lithiated molybdenum disulfide (LiMoS2) in the presence of cationic CdS nanocluster in heptane solution to obtain the semiconductor-semiconductor hybrid. Metal halide-superconducting oxide hybrids such as Agl-BSCCO and HgX2-BSCCO (X = Br, I) hybrids were also achieved via intercalation route, which can be considered as the excellent examples of inorganic/inorganic hybrid sysyem. On the other hands, the organic-inorganic hybrids were also demonstrated via intercalative complexation of iodine intercalated BSCCO with an organic salt of Py-CnH2n+1I (Py = pyridine). This superconducting hybrid has an unique structural feature with a sequential array of superconducting-insulating-superconducting-....layers along the c-axis, which can be regarded as a multilayered Josephson junctions, since each superdonducting block is completely isolated by insulating organic guest layer.