Magnetic-Field-Regulated ZnFe₂O₄ Nanospheres Interfacial Hydroxyl for Photocatalytic Air Purification

The presence of hydroxyl (OH) groups on the photocatalyst surface is crucial for the volatile organic compounds’ (VOCs) degradation. However, there is still limited knowledge on how OH groups are formed and their role in the magnetic-field-dependent photocatalytic degradation process. In this work, magnetic-field-assisted photocatalytic degradation of toluene was built by taking magnetic semiconductor material ZnFe 2 O 4 nanospheres as the photocatalyst. Through a combination of experimental techniques, in situ DRIFTS analysis, and DFT calculations, we discovered that applying a vertical magnetic field activated the OH groups on the surface of ZnFe 2 O 4, leading to an increase in the adsorption capacity of toluene. Additionally, the magnetic-field-induced Lorentz force facilitated the conversion of toluene to benzaldehyde, a significant step in the degradation process. As the magnetic field intensity increased, the way in which toluene was adsorbed changed. Overall, our study provides a valuable view for the role of OH groups and the effect of magnetic fields in the VOCs’ photocatalytic degradation.