Bifunctionalized Fe₇S₈@MoS₂–O core-shell with efficient photocatalytic activity based on internal electric field

The photocatalytic degradation of toxic water pollutants (dyes, antibiotics, microorganisms, etc.) have attracted much attention, but the lack of catalysts with strong visible light absorption and long carrier life have limited the sustainable development of clean water worldwide. In order to solve this problem, the one-pot hydrothermal method was employed to fabricate Fe₇S₈@MoS₂–O conduct-semiconductor-type catalyst for the first time. Fe₇S₈@MoS₂–O appears as a core-shell structure. Malachite green (MG) and Levofloxacin (LVX) could be efficiently decomposed by Fe₇S₈@MoS₂–O (75.7% and 81.3%, respectively) within 80 min and be further increased to 97.5% and 92.7% with peroxymonosulfate (PMS). The high disinfection performance for Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) are also obtained within 30 min (2.11 × 10⁷ cfu/mL of S. aureus and 2.96 × 10⁵ cfu/mL of E. coli inactivation). As a remarkable co-catalyst, the oxygen incorporated MoS₂ (MoS₂–O) was introduced into Fe₇S₈ to construct conductor-semiconductor-type heterojunction, which not only greatly facilitates Fe³⁺/Fe²⁺ cycle to yield a large number of active radicals but also builds a internal electric field (E-field) to accelerate charge carrier transport. The band structures of Fe₇S₈ and MoS₂ is conducted to elucidate the electronic structures of the photocatalyst according to the density functional theory (DFT) calculation. This study provides a strategy to design the efficient photocatalyst for environmental remediation.