Design of direct Z-scheme superb magnetic nanocomposite photocatalyst Fe3O4/Ag3PO4@Sep for hazardous dye degradation

Abstract Z-scheme Fe3 O4 /Ag3 PO4 @Sep magnetic nanocomposite photocatalyst was prepared via an eco-friendly co-precipitation approach. Various analytical methods were used to assess the structure, the morphology, and the optical absorption properties of the photocatalyst. The sepiolite as support of Ag3 PO4 and Fe3 O4 nanoparticles, prevented the aggregation and the photo-corrosion of the bare Ag3 PO4, and enhanced the photocatalytic stability and activity of the photocatalyst by a synergetic effect. Further, the band gap energy of the nanocomposite photocatalyst, as determined from the density functional theory calculations, was reduced, from 2.59 eV for Ag3 PO4 (1 1 0), and from 2.98 eV for Fe3 O4 (2 2 0), to about 2.37 eV for Fe3 O4 /Ag3 PO4 @Sep. The obtained dye degradation rate value of 0.480 min−1, was 69 times superior to pure Fe3 O4, 5 times higher than the bare Ag3 PO4, and 3 times higher than Ag3 PO4 @Sep. More importantly, Fe3 O4 /Ag3 PO4 @Sep shows continuous photocatalytic activity, even after three cycles of reuse.