Enhancing Organic Pollutant Degradation Efficiency through a Photocatalysis–Electro-Fenton System via MoS2 Crystal Morphology Regulation

A photocatalysis-electro-Fenton (PEF) system was constructed via molybdenum disulfide (MoS₂) to remove tetracycline (TC) without an external oxidant supply and solution pH adjustment. In the system, original graphite felt (GF) was used as a cathode, from which H₂O₂ was in situ generated continuously under power. MoS₂ was motivated by visible light to facilitate the cycle of Fe²⁺/Fe³⁺, enhancing the Fenton process to produce ^•OH. The experimental results showed that the system can increase the degradation rate of pollutants by more than 5 times. Moreover, the quenching and electron paramagnetic resonance (EPR) tests demonstrated that ^•OH was the dominant active species. X-ray photoelectron spectroscopy (XPS) characterization, Mo concentration, and cycle experiments proved the excellent catalytic activity and chemical stability of MoS₂. It is worth mentioning that the photocatalytic performances of different morphologies of MoS₂ (flower, flake, and radar) were compared. As a result, flower-like MoS₂ exhibited a much superior photoresponse than flake and radar, which could accelerate the Fe²⁺/Fe³⁺ cycle further effectively. These findings highlight the morphology-performance relationship of MoS₂ under a PEF system and the mechanisms of contaminant degradation, which is of great significance for developing photoelectric Fenton technology.