Magnetic field assisted α-Fe2O3/Zn1−xFexO heterojunctions for accelerating antiviral agents degradation under visible-light

Abstract

Reducing the recombination efficiency of photo-induced carriers has been found as an effective means to improve the degradation of antiviral agents. Given that the Lorentz forces can cause the abnormal charge to move in the opposite direction, external magnetic field improved α-Fe 2 O 3 /Zn 1-x Fe x O heterojunctions (FZHx) were developed to remove increasing antiviral agents that were attributed to the COVID-19 pandemic under visible light. The characterization of the mentioned FZHx in the external magnetic field indicated that FZHx had perfect photocatalytic activity for degrading antiviral agents. In the external magnetic field, the quantities of photo-generated carriers and free radicals (•OH and •O 2 - ) derived from FZHx increased significantly, which improved antiviral agent removal by 30.0%. Though the band structure (α-Fe 2 O 3 ) is unlikely to change due to some orders of magnitude weaker of Zeeman energy in magnetic fields, which insignificantly impacts photocatalytic performance. However, this study proposed a strategy of negative magnetoresistance effects and heterojunctions to facilitate the separation and transfer of photo-induced carriers in magnetic fields. Based on the proposed strategy, spin oriented electrons were selected and accumulated on the conduction band, which contributed to the degradation of antiviral agents. Overall, this study presented novel insights into the improved degradation performance of antiviral agents by applying Fe-based heterojunctions in an external magnetic field.

Electric effects reinforce charge carrier behaviour for photocatalysis

“…α-Fe 2 O 3 /Zn 1− x Fe x O heterojunctions (FZHx) were used for the removal of antiviral drugs (ribavirin, chloroquine phosphate, and arbidol), and the photocatalytic degradation efficiencies were increased by 42.4%, 45.4%, and 15.0%, respectively. 78 The synergistic effect of ferromagnetic α-Fe 2 O 3 , FZHx, and Fe 3+ incorporated into ZnO is a pivotal factor in improving carrier separation and transport efficiency. Negative magnetoresistance effects and heterojunctions synergistically inhibit the complexation of charge carriers to allow spin-oriented electrons to be selected and accumulated in the conduction band, which also contributed to the degradation of antiviral drugs.…”

Recent Advancements in Photocatalysis Coupling by External Physical Fields

“…In recent years, more and more attention has been paid to the promotion of magnetic fields on photocatalytic performance. In a magnetism-coupled photocatalytic system, the magnetic-field-induced Lorentz force diverts the charge from its original recombination path, leading to more carriers participating in the reaction, thereby enhancing the photocatalytic activity [206,213,216,225,226]. In addition, for materials with electron spin properties, the magnetic field can also enhance the electron-spin parallel alignment, which also has a positive effect on photocatalytic performance [209,217,227].…”