The photo-Fenton technique is a promising method for the degradation of contaminants of emerging concern (CEC) owing to its excellent capacity to produce highly oxidizing hydroxyl radicals. The ferrite group of materials are popular among the heterogeneous photo-Fenton catalysts because of the possibility of magnetic recovery of the catalyst after the reaction and their narrow band gap, which lies in the visible region. ZnFe₂O₄ (Zinc Ferrite, ZF) with a band gap of ~1.9 eV is an excellent material for absorbing light in the visible region. However, pristine ZF lacks the capacity to separate the photogenerated charge carriers. MoS₂ is a photocatalytic transition metal chalcogenide which has the potential to act as a co-catalyst in the photo-Fenton reaction. MoS₂ could enhance the Fe³⁺/Fe²⁺ redox cycle by converting Mo^IV to Mo^VI. Herein, a flower-like MoS₂ nanomaterial was incorporated into the synthesis of ZF and reported the formation of a MoS₂/ZF nanocomposite having a ZF outer shell with a MoS₂ core. XRD and Raman analysis of the flower-like MoS₂demonstrated the formation of MoS₂ with a 2H-crystal phase. Detailed characterization and validation of the synthesized materials were carried out through XRD, FTIR, XPS, Raman, BET, SEM, TEM and UV-DRS measurements. A modified synthesis protocol was followed to prepare another MoS₂/ZF nanocomposite catalyst with ZF decorated on the MoS₂flowers. The activity of the prepared catalysts was explored by monitoring their photo-Fenton degradation efficiency of Acetaminophen via HPLC analysis. The band alignments involved in the MoS₂/ZF nanocomposite formation, and the mechanism of efficient electron transfer between the MoS₂ and ZF are probed using DFT analysis. The interaction of H₂O₂ on the active catalytic surface, with the splitting of H₂O₂leading to the formation of reactive oxygen species and the degradation pathway followed by acetaminophen pollutant is also investigated by DFT studies. In conclusion, this study provides insights into the effective methodology for the fabrication of a MoS₂/ZF nanocomposite and provides a theoretical understanding of the mechanism behind the enhanced activity of the prepared MoS₂/ZF catalytic system.

Keerthi Manikandan Nair

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