MoSx co-catalytic activation of H₂O₂ by heterogeneous hemin catalyst under visible light irradiation

The slow Fe³⁺/Fe²⁺ conversion and difficult reactants contact are the main challenges for H₂O₂ activation using heterogeneous iron-based catalysts. As a typical two-dimensional layered nanomaterial, molybdenum sulfide holds great promise for promoting such process as co-catalysts, but its combination with solid iron catalysts is rarely reported. In this work, we fabricated a novel heterogeneous photocatalyst by directly anchoring amorphous MoSx onto the PAN fibers with hemin via an adsorption and in-situ transformation method. The detailed characterizations show the successful assembly of hemin and MoSx with the fibrous support through axial coordination and electrostatic bonding, respectively. Taking the degradation of organic dyes as model reactions, the as-prepared catalyst achieved remarkably high and stable catalytic performance in the presence of H₂O₂ under visible light irradiation, which was much superior to that of the single hemin or MoSx supported fibrous catalyst. The enhanced photocatalytic activity is mainly attributed to (i) the excellent adsorption capability of MoSx, which allows the catalyst to easily capture the reactants and (ii) the accelerated rate-limiting step of Fe³⁺/Fe²⁺ conversion. In addition, we also explored the MoSx co-catalytic effect on the other iron-based heterogeneous H₂O₂ activation systems (such as supported Fe³⁺ or FePc), and similar enhancing effect was observed. Our findings provide a facile and promising strategy to rationally design the advanced oxidation processes for environmental remediation.