Visible light photo-Fenton degradation of p-nitrophenol on Ag/Fe3O4/WO3 nanocomposites: Experimental and molecular dynamics investigations

The present research combines the adsorption behavior of phases in an aqueous medium with their band gap information for constructing a composite photo-Fenton catalyst that degrades para-nitrophenol (PNP). Thus, a series of Ag/ Fe3O4/WO3 Z-scheme photocatalysts were investigated for photo-Fenton PNP degradation. Classical MD simulations predicted effective H2O2 interaction with the photocatalyst's reduction (Fe3O4) part. The decoration of the composite surface by fine Ag nanostructures enhanced the visible light absorption efficiency of the photocatalyst through the localized surface plasmon resonance phenomenon. Photo-Fenton activities of Fe3O4/WO3 composites changed with their Ag loading. The composite with five-weight percent Ag loading demonstrated the best PNP degradation activity. The photoexcitation of Ag/Fe3O4/WO3 photocatalyst results in the accumulation of electrons on the CB of Fe3O4 and holes on the VB of WO3. The H2O2 molecules adsorb on the Fe3O4 part and are reductively cleaved to produce hydroxyl radicals, oxidizing PNP molecules nearby.