Design, synthesis and application of new iron-based cockscomb-like photocatalyst for high effectively degrading water contaminant under sunlight

[Display omitted] •Two unreported iron-based photocatalysts are designed and prepared.•Both catalysts exhibit 100% degradation rate to RhB solution under visible light.•2A5F@Fe3O4 shows a specific cockscomb-like 3D structure surface.•Improved degrading efficiency was confirmed both experimentally and theoretically.•The orthogonal experiments and degradation kinetic equations were screened. Developing cheap and efficient photocatalyst is a vigorous pathway for gradually increasing rhodamine B (RhB) pollution problem. Herein, two novel iron-based photocatalysts g-C3N4/ZnO@Fe3O4 (Fe-heterojunction) and 2-amino-5-fluorobenzotrifluoride@Fe3O4 (Fe-organic ligand) were designed and synthesized which exhibit 100% photo-degradative ability with water contaminant RhB under sunlight in about 2 h. They were characterized by SEM, FT-IR, XRD, XPS and BET as well as the analysis of morphological structure and chemical composition. The ESR experiment was also carried out to explore the possible degradation mechanism. The UV-Vis spectrum and band gap energies were examined and calculated. Especially, the Fe-organic ligand photocatalyst shows a specific 3D cockscomb-like structure. This makes its degrading efficiency much improved. The recently developed robust field-only surface integral method was employed to explore the possible mechanism which confirmed with the experimental results. The optimum degradation conditions including ligand ratio, pH and concentration of RhB solution, were screened by orthogonal experiments. Also, the reusability and degradation kinetic equations of the two photocatalysts were built to give a typical reference for a large-scale industrial wastewater treatment as well as for the water sustainable utilization.