Structure tunning of MoS2@Fe3O4 by modulating electron density for enhanced Fenton-like PMS activation: Accelerated Fe (III)/Fe (II) cycle for efficient micropollutants removal

Abstract

1T-MoS2 is a promising material for regulating the electronic structure of Fe-based catalyst to enhance PMS activation, due to the higher chemical reactivity of the basal plane with excellent intrinsic electronic properties. Herein, an excellent MoS2@Fe3O4 by using 1T- MoS2 as support to tune electronic structure, labeling as 1T-MoS2@Fe3O4, was successfully synthesized for faster and enhanced micropollutants degradation via Fenton-like peroxomonosulfate (PMS) activation. The composite showed remarkable catalytic performance, as evidenced by a removal rate of 1.12 × 10−1 min−1 for caffeine, which was 4.50 times higher than that of 2H-MoS2@Fe3O4, attributed to the robust capacity for Fe (II) regeneration. The efficiency of the 1T-MoS2@Fe3O4/PMS system was affected by pH, PMS and catalyst dosages, as well as water chemistry. Additionally, the potential mechanism for PMS activation was explored, showing that O2• were the dominant reactive oxygen species (ROS) generated in the system due to the electron-rich O sites on the composite, and electron transfer processes play an important role during PMS activation. The Mo (IV) active sites facilitated accelerated Fe (III)/Fe (II) cycle, which promoted the rapid PMS activation. Excellent degradation of micropollutants (MPs) mixture in real secondary effluent was achieved by 1T-MoS2@Fe3O4/PMS system. The possible degradation pathways of caffeine (CAF), ibuprofen (IBP), and carbamazepine (CBZ) were also investigated. This study offers a new perspective on MoS2 as a co-catalyst/support within Fenton-like system.