摘要
In this study, a novel visible-light-sensitive ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> photocatalyst has been fabricated by coupling 0.2-2 wt% p-type ZnFe <sub>2</sub> O <sub>4</sub> narrow bandgap material with n-type anatase TiO <sub>2</sub> for the enhanced photocatalytic degradation of organic dyes under 465 nm visible light irradiation. Transmission electron microscopy (TEM) and high resolution TEM confirm that ZnFe <sub>2</sub> O <sub>4</sub> and TiO <sub>2</sub> are strongly linked with an average particle size of 8-9 nm, leading to a decrease in hole-electron recombination rate as well as the enhanced photocatalytic activity of the ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> heterostructures under visible light irradiation. The optimized 1 wt% ZnFe <sub>2</sub> O <sub>4</sub> not only significantly extends the absorption edge of TiO <sub>2</sub> -based heterostructures to the visible light region but can also retain a stable photodegradation efficiency of >99% for at least 5 cycles. In addition, the photocatalytic activity of ZnFe <sub>2</sub> O <sub>4</sub> -TiO <sub>2</sub> toward dye decomposition follows the order cationic rhodamine B > neutral methyl red > anionic methyl orange. Our results clearly demonstrate that the coupling of a low loading mass of ZnFe <sub>2</sub> O <sub>4</sub> with anatase TiO <sub>2</sub> is a reliable green technology approach to prepare visible-light-responsive heterostructure photocatalysts with great potential for application in the decomposition of organic dyes and other emerging pollutants in the treatment of water and wastewater.