Effects of hydrothermal parameters on the physicochemical property and photocatalytic degradation of bisphenol A of Ti-based TiO2 nanomaterials

• Hydrothermal preparation parameters of Ti-based TiO 2 nanomaterials were optimized. • Hydrothermal growth of TiO 2 nanomaterials on the Ti plate conformed to Ostwald ripening mechanism. • The optimized TiO 2 nanosheets had a high photocatalytic degradation rate of BPA. • TiO 2 nanomaterials of designated morphology could be obtained by changing parameters. Effects of hydrothermal parameters on morphology, crystal structure, light absorption, separation efficiency of photo-generated charge carriers, and photocatalytic removal of Bisphenol A (BPA) of Ti-based TiO 2 nanomaterials were systematically investigated. Through changing hydrothermal parameters, TiO 2 nanobelts, TiO 2 nanosheets and TiO 2 nanowires were prepared. With increasing NaOH concentration, hydrothermal temperature, and hydrothermal time, more TiO 2 with (101) crystal plane grew on Ti substrate, resulting in higher crystallinity. The UV-light absorption enhanced with increasing NaOH concentration, but decreased with improving hydrothermal temperature, hydrothermal time, and HCl concentration. Variation of UV-light absorption was mainly affected by morphology, and UV-light absorption of TiO 2 nanomaterials with different morphologies was arranged in order of nanobelts > nanosheets > nanowires. The hydrothermal growth of TiO 2 nanomaterials on Ti plate conformed to Ostwald ripening mechanism. Variation trend of photo-generated current was consistent with that of BPA degradation, they both first increased and then decreased within investigated range. The optimal NaOH concentration, hydrothermal temperature, hydrothermal time, and HCl washing concentration were 1 M, 170℃, 28 h, and 0.1 M, respectively. Under this condition, Ti-based TiO 2 nanosheets exhibited the highest BPA removal efficiency (92.7%), which was due to highly ordered nanosheet structure, good crystallinity, appropriate UV-light absorption and high separation efficiency of electron-hole pairs.