Robust free standing flow-through TiO2 nanotube membranes of pure anatase

We report the fabrication of defect-free crystalline TiO2 nanotube (NT) membranes that maintain a full anatase phase composition up to an annealing temperature of 950 °C. Key is the use of a lactic acid electrolyte for the growth of the anodic nanotube layers. These nanotube layers are mechanically sufficiently robust to fabricate, by chemical etching, lift-off and annealing, both-end-open membranes that feature no morphological damage over their entire surface area and thickness. We illustrate the beneficial use of the pure anatase membranes for a flow-through photocatalytic application, i.e., the photodegradation of Acid Orange 7. However, it is anticipated that these pure anatase membranes will also have a wide range of uses in photo(electrochemical) applications of TiO2.