Persulfate activation by two-dimensional MoS₂ confining single Fe atoms: Performance, mechanism and DFT calculations

Developing efficient catalysts for persulfate (PS) activation is important for the potential application of sulfate-radical-based advanced oxidation process. Herein, we demonstrate single iron atoms confined in MoS₂ nanosheets with dual catalytic sites and synergistic catalysis as highly reactive and stable catalysts for efficient catalytic oxidation of recalcitrant organic pollutants via activation of PS. The dual reaction sites and the interaction between Fe and Mo greatly enhance the catalytic performance for PS activation. The radical scavenger experiments and electron paramagnetic resonance results confirm and SO₄^- rather than HO is responsible for aniline degradation. The high catalytic performance of Fe_0.36Mo_0.64S₂ was interpreted by density functional theory (DFT) calculations via strong metal-support interactions and the low formal oxidation state of Fe in Fe_xMo_1-xS₂. Fe_xMo_1-xS₂/PS system can effectively remove various persistent organic pollutants and works well in a real water environment. Also, Fe_xMo_1-xS₂ can efficiently activate peroxymonosulfate, sulfite and H₂O₂, suggesting its potential practical applications under various circumstances.