Chemical bonding character and physicochemical properties of mesoporous zinc oxide-layered titanate nanocomposites

We have investigated the chemical bonding character and physicochemical properties of mesoporous zinc oxide-layered titanate nanocomposites synthesized by an exfoliation-restacking route. According to our analyses using X-ray diffraction, high resolution transmission electron microscopy, and N₂ adsorption-desorption isotherm measurements, nanocrystalline zinc oxides are stabilized not only in the interlayer space of the host titanate but also in the mesopores of the nanocomposites formed by the house-of-card type stacking of the crystallites. X-ray absorption spectroscopic analyses at Ti K- and Zn K-edges clearly demonstrate that nanocrystalline zinc oxides crystallized with a Wurzite type structure, and the lepidocrocite structure of the host titanate remains unchanged after hybridization and postcalcination. Upon hybridization with zinc oxide nanoparticles, the photocatalytic activity of layered titanate is enhanced with respect to the oxidative photodegradation of phenol and dichloroacetate. But of greater importance is that the chemical stability of guest zinc oxide against acidic corrosion is greatly improved by hybridization with layered titanate. In this regard, the present hybridization technique enables the application of chemically unstable nanostructured zinc oxides even in corrosive environments.