Effect of Sb doping on the photocatalytic performance of Z-scheme TiO2NRA/SnO2/potassium titanate heterojunction and its photocatalytic mechanism

Abstract

Firstly, Sb–SnO2/potassium titanate (Sb–SnO2/K4TiO4 (KTO)) was fabricated by a sol-gel method, and then TiO2 nanorod arrays were grown on the surface of Sb–SnO2/KTO by a hydrothermal method (TiO2NRA/Sb–SnO2/KTO). The photocatalytic activity was evaluated by degrading tetracycline hydrochloride (TCH). The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), ultraviolet–visible diffuse reflectance spectrometer (UV–Vis), and X-ray photoelectron spectroscopic characterizations (XPS). The results show that the Z-scheme heterojunction formed between SnO2/KTO and TiO2 can enhance the range of light response. With the doping of Sb, the conductivity of the composite is enhanced, which is advantageous to the transfer of electron and the low recombination rate of electron-hole pairs. Thus, the doping of Sb is effective to improve the photocatalytic performance. Our work demonstrates the optimal doping amount of Sb is 5%. The degradation efficiency of TCH concentration can reach 95.6% after 2 h and TiO2NRA/Sb–SnO2/KTO shows good reusability.