Synthesis of stable burger-like α-Fe2O3 catalysts: Formation mechanism and excellent photo-Fenton catalytic performance

The application of iron-based photocatalysts has attracted wide attention. Herein, we reported a novel burger-like alpha-Fe2O3 catalyst, which was synthesized via facile hydrothermal method and used as a heterogeneous catalyst for photo-Fenton degradation of aquatic organic pollutants. More interesting, the alpha-Fe2O3 samples with spherical, elliptic, olive-like and burger-like morphologies could be obtained by adjusting the hydrothermal reaction time, respectively. Field emission scanning electron microscopy (FESEM) analysis showed that the burger-like alpha-Fe2O3 particles have convex waists and hemispherical ends, and are composed of many irregular nanoparticles. Furthermore, we proposed the probable growth mechanism involving oriented aggregation and Ostwald ripening of the burger-like structures. Under the optimum operating conditions, the burger-like alpha-Fe2O3 catalyst exhibited 98% degradation efficiency and 62% removal rate of COD for acid red G (ARG) in aqueous solution. In addition, the spheroidal structure showed the excellent stability, the burger-like alpha-Fe2O3 catalyst still remained high catalytic activity after six cycling experiments, and the leached iron value accounted for only 0.32 wt parts per thousand of the iron content in the catalyst. This work might offer a new viewpoint for the development of sufficiently stable and highly efficient iron-based heterogeneous catalyst. (C) 2018 Elsevier Ltd. All rights reserved.