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

Abstract

• Z-scheme Fe 3 O 4 /Ag 3 PO 4 @Sep magnetic nanocomposite photocatalyst is synthesized. • Synergy between Fe 3 O 4 , Ag 3 PO 4 , and Sepiolite is crucial for enhanced photocatalysis. • Holes and hydroxyls radicals are the main reactive species for MG dye degradation. Z-scheme Fe 3 O 4 /Ag 3 PO 4 @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 Ag 3 PO 4 and Fe 3 O 4 nanoparticles, prevented the aggregation and the photo-corrosion of the bare Ag 3 PO 4 , 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 Ag 3 PO 4 (1 1 0), and from 2.98 eV for Fe 3 O 4 (2 2 0), to about 2.37 eV for Fe 3 O 4 /Ag 3 PO 4 @Sep. The obtained dye degradation rate value of 0.480 min −1 , was 69 times superior to pure Fe 3 O 4 , 5 times higher than the bare Ag 3 PO 4 , and 3 times higher than Ag 3 PO 4 @Sep. More importantly, Fe 3 O 4 /Ag 3 PO 4 @Sep shows continuous photocatalytic activity, even after three cycles of reuse.