An array of transition metal tubular architectures, where the transition metal tubular architectures are comprised of a transition metal oxide, sulfide, or selenide, and wherein transition metal tubular architectures are less than 100 nm in length. The transition metal tubular architectures can be at least partially crystalline. Within the array of transition metal tubular architectures, at least 80% of the transition metal tubular architectures can be less than 100 nm in length.

An array of transition metal tubular architectures, where the transition metal tubular architectures are comprised of a transition metal oxide, sulfide, or selenide, and wherein transition metal tubular architectures are less than 100 nm in length. The transition metal tubular architectures can be at least partially crystalline. Within the array of transition metal tubular architectures, at least 80% of the transition metal tubular architectures can be less than 100 nm in length.

A dielectric powder includes a core-shell structure including a core region formed in an inner portion thereof and a shell region covering the core region. The core region includes barium titanate (BaTiO.sub.3) doped with a metal oxide, and the shell region is formed of a ferroelectric material.

A dielectric powder includes a core-shell structure including a core region formed in an inner portion thereof and a shell region covering the core region. The core region includes barium titanate (BaTiO.sub.3) doped with a metal oxide, and the shell region is formed of a ferroelectric material.

The present invention provides a method for preparing a transparent free-standing titanium dioxide nanotube array film. In the method, with the titanium foil as a substrate, the titanium dioxide nanotube array film is obtained by anode oxidation on the surface of the titanium foil. Upon high temperature annealing, the titanium dioxide nanotube array film naturally falls off to obtain the transparent free-standing titanium dioxide nanotube array film. The method according to the present invention features simple operations, saves time and cost. With the method, a completely strippable titanium dioxide nanotube array film may be prepared, and in addition, morphology of the titanium dioxide nanotube is not damaged. The free-standing and complete titanium dioxide nanotube array film facilitates transfer and post-treatment, has the feature of transparency and may be in favor of the applications to the studies such as photocatalysis and the like.

The present invention provides a method for preparing a transparent free-standing titanium dioxide nanotube array film. In the method, with the titanium foil as a substrate, the titanium dioxide nanotube array film is obtained by anode oxidation on the surface of the titanium foil. Upon high temperature annealing, the titanium dioxide nanotube array film naturally falls off to obtain the transparent free-standing titanium dioxide nanotube array film. The method according to the present invention features simple operations, saves time and cost. With the method, a completely strippable titanium dioxide nanotube array film may be prepared, and in addition, morphology of the titanium dioxide nanotube is not damaged. The free-standing and complete titanium dioxide nanotube array film facilitates transfer and post-treatment, has the feature of transparency and may be in favor of the applications to the studies such as photocatalysis and the like.

A radioactive cesium adsorbent includes photocatalyst particles and Prussian blue. The ferric ions of the Prussian blue are reduced to ferrous ions by activation of the photocatalyst particles. A method of removing radioactive cesium using the radioactive cesium adsorbent includes preparing a composition comprising photocatalyst particles and Prussian blue; preparing a precursor solution by mixing radioactive cesium and the composition prepared in the preparing of a composition; and reducing ferric ions of the Prussian blue to ferrous ions by activating the photocatalyst particles in the precursor solution prepared in the preparing of a precursor solution.

A radioactive cesium adsorbent includes photocatalyst particles and Prussian blue. The ferric ions of the Prussian blue are reduced to ferrous ions by activation of the photocatalyst particles. A method of removing radioactive cesium using the radioactive cesium adsorbent includes preparing a composition comprising photocatalyst particles and Prussian blue; preparing a precursor solution by mixing radioactive cesium and the composition prepared in the preparing of a composition; and reducing ferric ions of the Prussian blue to ferrous ions by activating the photocatalyst particles in the precursor solution prepared in the preparing of a precursor solution.

The titanium oxide powder of the present invention is a titanium oxide powder having a BET specific surface area of 5 m.sup.2/g or more and 15 m.sup.2/g or less and containing polyhedral-shaped titanium oxide particles having eight or more faces, in which an L value in Lab color space thereof is 75 or higher.

The titanium oxide powder of the present invention is a titanium oxide powder having a BET specific surface area of 5 m.sup.2/g or more and 15 m.sup.2/g or less and containing polyhedral-shaped titanium oxide particles having eight or more faces, in which an L value in Lab color space thereof is 75 or higher.