CuS-MIL-53(Fe) Framework as a Heterogeneous Fenton Catalyst for the Removal of Organic Contaminants

Developing a suitable Fenton catalyst capable of efficient redox cycling between Fe³⁺ and Fe²⁺ for dye degradation is a promising approach for enhancing catalytic activity. In this work, we synthesized a rod-like CuS-MIL-53(Fe) framework via a solvothermal process. The incorporation of CuS into pristine MIL-53(Fe) induced a significant structural transformation from an octahedral to a rod-like morphology, resulting in an enhanced surface area from 130.50 m²/g (MIL-53(Fe)) to 182.96 m²/g (CuS-MIL-53(Fe)), as confirmed by BET analysis. The composite demonstrated excellent performance in the Fenton reaction, achieving 94.4% removal of methylene blue (MB) within 50 min with a rate constant of 0.052 min^-1. In contrast, MIL-53(Fe) achieved only 64.4% degradation in the same time frame, with a lower rate constant of 0.020 min^-1 under identical reaction conditions. Both X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses indicated interfacial electron movement from CuS into MIL-53(Fe), which resulted in a 30% increase in catalytic performance for methylene blue decomposition using the CuS-MIL-53(Fe) catalyst, as compared to that of pristine. The primary reactive species driving the degradation process were identified as hydroxyl radicals (^•OH). The composite maintained its catalytic efficiency even after five cycles, reflecting its superior stability. This investigation centers on the fabrication of new Fenton catalysts aimed at improving environmental decontamination methods.