(1T/2H)-MoS2/CoFe2O4 heterojunctions with a unique grape bunch structure for photocatalysis of organic dyes driven by visible light

The formation of heterostructures is an effective way to tune the band structure and photocatalytic property. Herein, an efficient (1T/2H)-MoS2/CoFe2O4 heterojunction was prepared via a facile green hydrothermal method and performed well in the photocatalytic removal of organic dyes. By varying the molar ratio of MoS2 versus CoFe2O4, the photogenerated electron-hole separation can be enhanced in the heterojunction. The MoS2/CoFe2O4 composite with a 2:1 M ratio of MoS2 to CoFe2O4 (MC-2) shows the best photocatalytic performance, where 91.9 % of methyl blue (MB) is degraded within 60 min and its apparent rate constant is 5.94 and 25.43 times higher than those of pure MoS2 and CoFe2O4. In addition, MC-2 maintains high photocatalytic performance even in an aqueous environment similar to wastewater, where some different inorganic ions (e.g., NO3–, CO32– and SO42–) are present. Further, the remarkable ferromagnetic property of MC-2 at room temperature ensures that the composites were easy to be separated from the wastewater. Meanwhile, the as-synthesized composites exhibit good reusability. A possible mechanism for photodegradation of MB is proposed for (1T/2H)-MoS2/CoFe2O4 heterojunction by the analyses of the energy bands and the trapping experiments of active species.