Visible-light photo-Fenton catalytic MgFe2O4 spinel: Reaction sintering synthesis and DFT study

Abstract MgFe2O4 spinel has attracted extensive attention as a photo-Fenton catalyst that can be used to degrade dyes in water under visible light. In this work, the MgFe2O4 spinel synthesized via reaction sintering was first used as a photo-Fenton catalyst to degrade Rhodamine B(RhB) under visible light. Furthermore, the influence of pH, MgFe2O4 spinel catalysts and H2O2 content on reaction activity was systematically investigated. The electronic structure of as-made MgFe2O4 spinel was explored by the DFT theoretical calculations, which revealed the composition of the valence band and conduction band. The prepared MgFe2O4 spinel was a mesoporous material with ferromagnetism, suitable band structure, and good visible light response. Various iron active sites on the MgFe2O4 surface interacted with H2O2 to produce a large amount of hydroxyl radical (·OH), which made the degradation efficiency of RhB reach up to 98.55% and the removal efficiency of TOC was 78.12%. After seven recycles, the efficiency was still above 94%. MgFe2O4 spinel was shown to be a simple-to-recycled, stable, and effective photo-Fenton catalyst with a potential practical application value.