An efficient visible‐light active photocatalyst of porous CrOx–Ti1.83O4 nanohybrid with a 1:1 type ordered heterostructure is synthesized through a hybridization between a chromia cluster and exfoliated titanate nanosheets. The present nanohybrids are found to have a large surface area (ca. 250–310 m2 g–1) and an intense absorption of visible light, ascribable, respectively, to the formation of a porous structure and the hybridization of titanate with narrow‐bandgap chromium oxide. After the calcination at 400 °C, the nanohybrid shows an enhanced photocatalytic activity to effectively decompose organic compounds under the irradiation of visible light (λ > 420 nm). The present study highlights the exfoliation–restacking route as a very powerful way to develop efficient visible‐light‐harvesting photocatalysts with excellent thermal stability.

The effect of cation substitution on the crystal and electronic structures of ferroelectric bismuth titanate has been systematically investigated. According to the x-ray diffraction analyses on Bi3.25A0.75Ti3O12 (A=Bi, La, Gd, and Y), it was found that the cation substitution gives rise to the contraction of the volume of the unit cell and to the decrease of the structural distortion of the bismuth titanate, as well. The present x-ray absorption spectroscopic results reveal that the local structural change upon chemical reduction is remarkably depressed by the cation substitution through the enhancement of (TiO) bonds. Such a stabilization of TiO6 octahedra can be understood by a competition between adjacent (BiO) and (TiO) bonds as well as the contraction of the unit cell.

We have synthesized heterostructured zinc oxide-aluminosilicate nanohybrids through a hydrothermal reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and the sol solution of zinc acetate. According to X-ray diffraction, N2 adsorption-desorption isotherm, and field emission-scanning electron microscopic analyses, it was found that the intercalation of zinc oxide nanoparticles expands the basal spacing of the host montmorillonite clay, and the crystallites of the nanohybrids are assembled to form a house-of-cards structure. From UV-vis spectroscopic investigation, it becomes certain that calcined nanohybrid contains two kinds of the zinc oxide species in the interlayer space of host lattice and in mesopores formed by the house-of-cards type stacking of the crystallites. Zn K-edge X-ray absorption near-edge structure/extended X-ray absorption fine structure analyses clearly demonstrate that guest species in the nanohybrids exist as nanocrystalline zinc oxides with wurzite-type structure.

Zinc oxide-layered titanate nanohybrids with a 1 ratio 1 ordered heterostructure have been successfully synthesized by reassembling exfoliated titanate nanosheets in the sol solution of zinc acetate under hydrothermal conditions.