Heterostructured ZnFe2O4/TiO2 nanocomposites with a highly recyclable visible-light-response for bisphenol A degradation

Abstract

Novel visible-light-sensitive ZnFe2O4-TiO2 heterojunction photocatalysts are successfully fabricated by a facile solvothermal method for the enhanced photocatalytic degradation of bisphenol A (BPA) under different light sources. The photocatalytic degradation efficiency and rate of BPA by ZnFe2O4-TiO2 under the irradiation of different light sources follow the order 465 nm visible light > solar simulator > 365 nm UV light. The reaction rate of BPA by ZnFe(2)O(4-)TiO2 in the presence of 465 nm visible light is 42 times higher than that under 365 nm UV light irradiation. In addition, the ZnFe2O4-TiO2 nanocomposites exhibit excellent recycling and reusability and can retain their stable photocatalytic activity toward BPA photodegradation for at least 10 cycles of reaction with rate constants of 0.191-0.218 min(-1) under visible light irradiation. The photogenerated holes as well as oxygen-containing radicals are identified to be the predominant reactive species responsible for the photodegradation of BPA in the ZnFe2O4-TiO2 system. The possible reaction mechanisms for BPA photodegradation by p-n heterojunction ZnFe2O4-TiO2 are also proposed. Results obtained in this study clearly demonstrate the superior visible-light-driven photoactivity of ZnFe2O4-TiO2 toward BPA photodegradation and can open an avenue to fabrication of p-n heterojunctions of photocatalysts with a wide variety of potential applications in the fields of photocatalysis, water splitting and energy conversion.