Magnetic Ag3PO4/Ag2CrO4/Fe/Fe3O4 quaternary composite for improved solar-driven photocatalytic degradation of cationic dyes under natural solar radiation

Abstract

To improve the visible light utilization for degradation of dye pollutants, novel magnetic Ag3PO4/Ag2CrO4/Fe/Fe3O4 composite has been synthesized for the first time via a simple two-step process including solvothermal route and co-precipitation method. The as-fabricated Ag3PO4/Ag2CrO4/Fe/Fe3O4 composite were characterized by using XRD, FE-SEM, TEM, EDS, VSM, PL, FTIR and UV–vis DRS for the crystal structures, chemical compositions, morphologies, optical and photocatalytic properties. As-fabricated composite used for degradation of binary mixture of Methylene Blue (MB) and Rhodamine B (RhB) under solar irradiation. The Ag3PO4/Ag2CrO4/Fe/Fe3O4 composite photocatalyst exhibited high degradation activity compared to Fe/Fe3O4, Ag2CrO4/Fe/Fe3O4, Ag3PO4/Fe/Fe3O4, Ag3PO4/Ag2CrO4 under solar light irradiation. Due to the good conductivity, the electrons in Ag3PO4 and Ag2CrO4 could be transported to Fe/Fe3O4, which inhibited the recombination of electron-hole pairs. In addition, the role of Fe/Fe3O4 in the photocatalytic mechanism is also discussed in detail. The optimum conditions were found to be 60 min, 7.0, 0.025 g, 12.0 and 4.0 mg/L for irradiation time, pH, photocatalyst dosage and initial concentration of MB and RhB, respectively. At the optimum condition, the photocatalytic degradation percentages of MB and RhB were found to be 93.37 and 71.22%, respectively. The increased photocatalytic activity of prepared magnetic composite is attributed to expanded absorption in the visible light region, and formation of the S-scheme system.