Novel magnetically separable Ag3PO4/MnFe2O4 nanocomposite and its high photocatalytic degradation performance for organic dyes under solar-light irradiation

Abstract

Novel magnetically separable Ag3PO4/MnFe2O4 nanocomposite with 30wt% MnFe2O4 was synthesized for the first time by a facile hydrothermal route and the composition and microstructure of the nanocomposite was fully characterized. The photocatalytic activity of Ag3PO4/MnFe2O4 nanocomposite was evaluated in the degradation of methylene blue (MB) and Rhodamine B (RhB) dyes under natural solar-light irradiation with an average light intensity of ~ 185mWcm−2. The results displayed that the degradation efficiency of the Ag3PO4/MnFe2O4 nanocomposite was 98% for methylene blue (MB) and 100% for Rhodamine B (RhB) in 82min. The photocatalytic activity of Ag3PO4/CoFe2O4 was almost 1.5 and 3 times as high as those of the pure Ag3PO4 and CoFe2O4, respectively. The remarkably enhanced photocatalytic performance of Ag3PO4/MnFe2O4 nanocomposite compared with the individual Ag3PO4 and MnFe2O4 was ascribed to its higher specific surface area and the existence of a synergic effect between Ag3PO4 and MnFe2O4 that resulted in efficient separation of electron–hole pairs. Trapping experiments indicated that the photodegradation of dyes was mainly achieved by superoxide radicals (•O2-) attack in Ag3PO4/MnFe2O4 suspension. Furthermore, the possible mechanism of excellent solar-light photoactivity activity of the Ag3PO4/MnFe2O4 nanocomposite was proposed based on the experimental results. Due to the existence of the magnetic MnFe2O4 nanoparticles, the Ag3PO4/MnFe2O4 nanocomposite could be magnetically separated from the reaction mixture by a usual magnet with an intensity of 0.1T (= 1kOe) and reused without any change in structure.