Preparation of Bi4Ti3O12/TiO2 by flame spray pyrolysis for photoelectrocatalytic degradation of tetracycline

The negative effects of the irrational use of antibiotics have been increasing attention from the public, making it urgently needed to develop effective techniques for removing antibiotics from wastewater. Simultaneously, the construction of heterogeneous TiO2 photoanodes can be used to enhance photoelectrocatalytic performance. Herein, we used an advanced method, namely one-step flame spray pyrolysis (FSP) to in-situ prepare Bi4Ti3O12/TiO2 heterostructures. The ultra-high temperature characteristics of this method facilitated the high dispersion of Bi species on TiO2, leading to the formation of the Bi4Ti3O12 phase within milliseconds. Bi4Ti3O12 forms a "Z" type heterojunction with TiO2, improving charge separation and enhancing electron transfer efficiency. The photoeletrocatalytic degradation effect of Bi4Ti3O12/TiO2 on tetracycline is significantly improved. Under simulated sunlight irradiation for 75 min and 1V voltage, the removal of tetracycline can reach 99.7%. The recycling degradation experiments demonstrated the remarkable reusability and stability of Bi4Ti3O12/TiO2, while the evaluation of degradation intermediates and toxicity analysis of tetracycline were also conducted. Furthermore, free radical trapping experiments confirmed that hydroxyl radicals and holes play a significant role in the removal of tetracycline.