Exfoliation of Layered Transition Metal Oxides: Formation of Functional Oxide Nanosheets and Their Applications

抄録

Unilamellar two-dimensional crystallites of transition metal oxides, T1_0.910₂, Ca₂Nb₃O₁₀ and Mn0₂, have been derived by delaminating layered host precursors via intercalation of quaternary ammonium ions. The nanosheets are characterized by their high two-dimensional anisotropy with a molecular thickness, and this structural feature yields novel physicochemical properties. A range of useful nanostructured materials can be fabricated by organizing these nanosheets as a building block through various wet processes. Flocculation induced by the addition of appropriate cationic species can produce restacked lamellar aggregates, through which functional materials, e.g. porous or fluorescent materials, can be designed by the selection of the nanosheets and combined flocculating agents. The sequential adsorption procedure via electrostatic self-assembly can be employed to deposit the nanosheets layer-by-layer with polycations, which can lead to multilayer ultrathin films and hollow nanospheres.