Varied crystalline orientation of anatase TiO2 nanotubes from [101] to [001] promoted by TiF6 2− ions and their enhanced photoelectrochemical performance

Herein, we report an ionic cross-linkage process of synthesizing [001] preferred oriented anatase TiO 2 nanowires and nanotubes hybrid structure (TWTs) based on anodization method wherein varied amounts of TiF 6 2− ions are added in synthetic process. We show how the TiF 6 2− ions switch the growth direction of TWTs from [101] to [001] (denoted as T 101 WTs and T 001 WTs, respectively) and change their geometrical morphologies, i.e., small ionic radii TiF 6 2− ions migrate and partly replace the TiO 6 2− octahedra under electric field, which separate out and leave vacancies during annealing process, resulting in a reconstruction of TiO 2 . Importantly, absorption property and photoelectrochemical (PEC) performance of T 001 WTs exceed those of T 101 WTs. Furthermore, CdS QDs are assembled onto TWTs photoelectrodes by successive ionic layer adsorption and reaction technique. Likewise, T 001 WT/CdS presents superior absorption capability and enhanced PEC performance to those of T 101 WT/CdS. This could be attributed to their preponderances of improved light absorption capability and decreased electron recombination.