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

A novel magnetic Fe 3 O 4 @SiO 2 @BiFeO 3 /rGO composite was successfully fabricated via a facile hydrothermal method . This composite consisted of flower-like core-shell structured Fe 3 O 4 @SiO 2 @BiFeO 3 microspheres mounting on reduced graphene oxide (rGO) nanosheets . The specific surface areas, magnetization saturation value ( M s ), and band gap energy ( E g ) of Fe 3 O 4 @SiO 2 @BiFeO 3 /rGO (x = 0.15 g) were 139.26 m 2 /g, 20.3 emu/g, and 1.91 eV, respectively. Fe 3 O 4 @SiO 2 @BiFeO 3 /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 Fe 3 O 4 @SiO 2 @BiFeO 3 /rGO conformed to a first-order kinetic reaction, and the corresponding k app values by Fe 3 O 4 @SiO 2 @BiFeO 3 /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 E g , 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.