Magnetic Fe3O4@SiO2@BiFeO3/rGO composite for the enhanced visible-light catalytic degradation activity of organic pollutants

Abstract

A novel magnetic Fe3O4@SiO2@BiFeO3/rGO composite was successfully fabricated via a facile hydrothermal method. This composite consisted of flower-like core-shell structured Fe3O4@SiO2@BiFeO3 microspheres mounting on reduced graphene oxide (rGO) nanosheets. The specific surface areas, magnetization saturation value (Ms), and band gap energy (Eg) of Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 139.26 m2/g, 20.3 emu/g, and 1.91 eV, respectively. Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) exhibited remarkable ability to photocatalytically degrade ciprofloxacin (CIP), tetracycline hydrochloride (TC-H), methylene blue (MB), and decolorize a mixed solution of MB, methyl orange (MO), and rhodamine B (Rh B); CIP, TC-H, and MB degradation by Fe3O4@SiO2@BiFeO3/rGO conformed to a first-order kinetic reaction, and the corresponding kapp values by Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 0.04211, 0.02792, and 0.05967 min−1, respectively. Excellent magnetic separation performance, recyclability, and stability were also observed. A suitable amount of rGO to the as-prepared photocatalyst could decrease the Eg, accelerate the transfer of photogenerated electrons (e−), suppress the recombination of photo-generated e−–hole (h+) pairs, and enhance the visible-light response of the catalyst. The •OH is the dominant active species during photocatalysis. This work suggests a promising strategy to synthesize photocatalysts with enhanced ability to catalytically degrade organic pollutant under visible light and excellent recyclability.