Effect of post heat treatment on microstructure and photocatalytic activities of TiO2 nanoribbons

► TiO2 nanoribbons were synthesized by a modified hydrothermal method. ► After post heat treatment, plenty of holes were observed on the surface of nanoribbons. ► The size of the holes increased with the calcination temperature increasing. ► The samples annealed at 800 °C for 1.5 h and 600 °C for 2.5 h showed the best photocatalytic activity.