Sol–gel template synthesis and characterization of aligned anatase-TiO2 nanorod arrays with different diameter

Template-based growth has been demonstrated as an attractive method for the synthesis of oxide nanorod arrays. In this paper, TiO2 nanorod arrays in anodic alumina membranes have successfully been synthesized by an improved sol–gel template method. TiO2 nanorods were obtained to injection of prepared TiO2-sol from the sol–gel process and then the samples were immediately immersed into boiling TiO2-sol solutions. Aligned TiO2 nanorod arrays were polycrystalline anatase-phase after annealing at 400 °C for 2 h with diameters about 160–250, 80–130 and 40–70. A lateral shrinkage approximately 15–20% was found in TiO2 nanorods with respect to the template pore diameter. This size difference is likely due to the volume shrinkage caused by removing residual materials and densification during annealing.