Efficient fabrication of robust and highly ordered free-standing TiO2 nanotube layers

•The anodization of Ti in aged electrolyte facilitates the formation of well-aligned and highly ordered TiO2 nanotubes•Morphology, physicochemical stability of TiO2 nanotube arrays and the detachment route define the quality of the obtained free-standing TiO2 nanotube layer•Nanoribs function as connectors and may help keep the nanotubes close together and reinforce arrays to prevent their deconstruction during detachment A free-standing TiO2 nanotube layer (FSL-TiO2NTs) was prepared via a three-step process, including the electrochemical anodization of Ti foil, calcination at 500 °C for 2 h in air, and detachment with 5.0 wt.% H2O2. The physicochemical properties of TiO2NTs grown on a Ti substrate (TiO2NTs/Tisub) and FSL-TiO2NTs obtained from electrolytes aged for different times (i.e., 0, 4, 8, or 12 h) were characterized by current density measurements, FE-SEM, TEM, XRD, UV–Vis absorbance spectroscopy and transient photocurrent measurement. In general, TiO2NTs synthesized in electrolytes aged for 8 and 12 h possessed not only a highly-ordered structure but also sufficient mechanical hardness to resist the detachment drag, resulting in FSL-TiO2NTs with a complete nanotubes layer structure. The materials prepared in this work demonstrate excellent potential for future applications. [Display omitted]