Facile fabrication of sulfuretted NiFe-layered double hydroxides/oxalic acid induced g-C3N4 Z-scheme heterojunction for enhanced photocatalytic removal of tetracycline and Cr(VI) under visible light irradiation

Novel sulfuretted NiFe-layered double hydroxides/oxalic acid induced g-C3N4 (NFS/OCN) heterostructures have been fabricated via a simple method and studied as photocatalysts for removal of tetracycline (TC) and Cr(VI) under visible light irradiation. Several advanced characterizations (XRD, SEM, TEM, XPS, PL, UV-Vis DRS, PL, etc.) were applied to identify its structure information of the as-obtained catalysts concerning the generation of the NFS sample, the presence of the heterojunction between NFS and OCN as well as triumphant incorporation of O into the structure of CN. In detailed, the photocatalytic removal efficiencies towards TC and Cr(VI) were 85.88 % and 93.69 % under the optimal conditions, which was ascribed to the enhanced light-harvesting ability, well transfer and separation efficiency of photo-generated carriers through the unique Z-scheme heterojunction structure. At last, the possible photocatalytic reaction mechanism is proposed.