3D CoFe2O4 nanorod/flower-like MoS2 nanosheet heterojunctions as recyclable visible light-driven photocatalysts for the degradation of organic dyes

A novel 3D heterojunction consisting of CoFe2O4 nanorods loaded with flower-like MoS2 nanosheets was synthesized by electrospinning combined with a one-step hydrothermal technique. The structure, morphology and composition of the as-synthesized CoFe2O4/MoS2 composites were characterized by XRD, SEM, TEM, XPS and PL. Results confirm the formation of the heterojunction and the coverage of flower-like MoS2 nanosheets on the surface of CoFe2O4 nanorods. Notably, the CoFe2O4/MoS2 heterojunction shows high photocatalytic ability for the degradation of organic dyes under visible light irradiation. As to Congo red (CR) degradation, the sample with the 50% molar ratio of MoS2 exhibits the highest photocatalytic activity, where the initial rate constant is about 12 times higher than that of pure MoS2. Herein, the photocatalytic degradation efficiency for CR of this product is 94.9%, further, the photocatalytic ability for the degradation of anion methyl orange (MO) and cation methylene blue (MB) is also presented. The enhanced photocatalytic activity of the CoFe2O4/MoS2 heterojunction originates from the synergistic effect of CoFe2O4 nanorods and flower-like MoS2 nanosheets, efficient separation of photogenerated charge carriers and the reduced recombination of photogenerated electron-hole pairs. Additionally, the remarkable magnetic performance of CoFe2O4 in the heterojunction guarantees their easy separation and recycling. The possible degradation pathway and photocatalytic mechanism were proposed, where it is pointed out that radOH, radO2− and h+ are the active species in the photocatalytic reaction. The inspiring visible light-driven photocatalytic ability of as-synthesized CoFe2O4/MoS2 heterojunction identifies their potential and promising application in the treatment of industry wastewater.