Facile synthesis of novel ZnFe2O4/CdS nanorods composites and its efficient photocatalytic reduction of Cr(VI) under visible-light irradiation

[Display omitted] •Novel ZnFe2O4/CdS composites were successfully fabricated by a facile method.•ZnFe2O4/CdS composites were used in photocatalytic reduction of aqueous Cr(VI).•ZnFe2O4/CdS composites exhibited remarkable visible-light photocatalytic activity.•ZnFe2O4/CdS composites showed good photocatalytic stability.•Visible-light photocatalytic mechanism of ZnFe2O4/CdS composites was discussed. ZnFe2O4/CdS composites were successfully prepared by a facile process. The obtained samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), diffuse reflection spectroscopy (DRS), Raman spectroscopy and photoluminescence (PL). Under visible light irradiation, ZnFe2O4/CdS composite shows higher photocatalytic activity in the Cr(VI) reduction, relative to the pure CdS and ZnFe2O4. The enhanced photocatalytic performance was ascribed to the intimate contact interfaces and matching band potentials between CdS and ZnFe2O4, and can be related to the efficient transfer and separation of the electron-hole pairs. It was found that the modification of ZnFe2O4 did not affect the morphology of CdS. The result of PL test indicated a lower intensity, and effective separation of photogenerated electron-hole pairs. In addition, the ZnFe2O4/CdS composites showed more intense optical absorption than that of pure CdS and ZnFe2O4. Through the analysis of experiment results, a reasonable photocatalytic mechanism over ZnFe2O4/CdS photocatalysts was also proposed.