Layered nanostructures of delaminated anatase: Nanosheets and nanotubes

Anatase, viewed traditionally as a three-dimensional TiO2 structure, has major applications in solar cells, hydrogen production, and catalysis. Here, we report the synthesis, characterization, and structural simulation of a layered nanosheet material that can be described as delaminated anatase along the [00 1] direction. Counting the outer and interlayer surfaces, such a nanosheet structure maximizes the areas of surfaces which are similar to anatase (001), believed to be the surface of central importance for the superior efficiency of anatase in various applications. Indeed, the important dissociative adsorption process of water predicted to occur on the anatase (001) surface is observed in such nanosheet material. It is also shown that the structure of titania nanotubes, an issue of debate for nearly a decade, can also be described by delaminated anatase along the [001] direction. Interestingly, the strains in such a curved tubular structure lead to major differences in surface chemistry such as water dissociation.