Hydrothermal growth of multi-facet anatase spheres

Titania with various nanostructures can be synthesized by several F−-mediated procedures. In this paper, we report the synthesis of a novel multi-facet microsphere consisting of etched single-crystalline anatase by simply immersing metallic Ti plates in an HF aqueous solution under hydrothermal conditions. The etched multi-facet sphere was found to grow through the nucleation and growth of truncated bipyramids on a previously precipitated one to assemble a microsphere, and its subsequent etching by HF to expose the thermodynamic stable {1 0 1} facets. The photocatalytic activity of such etched multi-facet sphere thin films was evaluated utilizing rhodamine B and sulfonic salicylic acid in water as target molecules and compared with commercial Degussa P25 titania nanoparticles.