Hydrothermal-assisted synthesis of the multi-element-doped TiO2 micro/nanostructures and their photocatalytic reactivity for the degradation of tetracycline hydrochloride under the visible light irradiation

Abstract The TiO 2 and copper-containing TiO 2 (Cu-TiO 2 ) micro/nanostructures are synthesized using a multi-element-doping route, and their visible-light-induced photocatalytic degradation of tetracycline hydrochloride (TC) is evaluated. Using metallic Ti powders with impurities as raw material, these two cauliflower-like micro/nanostructures can be hydrothermally synthesized through a dissolution and hydrolysis process in the NH 4 HF 2 solution and NH 4 HF 2 +CuSO 4 solution, respectively. Then, after a calcining treatment at 600 °C for 2 h, their phase compositions can be transformed from anatase to mixed anatase-rutile, the optical absorption edges are decreased from 452 and 439 nm to 569 and 581 nm, respectively. The apparent reaction rate constants for the photodegradation reaction of TC over the calcined TiO 2 and Cu-TiO 2 samples, which can be described by pseudo-first-order kinetics model, are increased from 0.00313 min −1 and 0.00407 min −1 to 0.00468 min −1 and 0.00978 min −1 , respectively. The enhanced photocatalytic degradation abilities of these TiO 2 and Cu-TiO 2 are attributed to their unique mixed phase composition and optical properties, and the trace doped Fe, Cu, F and N elements in their structure.