Synergistic Fe Doping and Oxygen Vacancies in MoO3 Nanosheets for Enhanced Local Surface Plasmon Resonance-Driven Visible-Light Photocatalysis.

Doping has emerged as a prominent strategy to promote the separation of photogenerated charge carriers, thereby boosting the overall photocatalytic performance. In this work, Fe-doped MoO3 nanosheets were fabricated via a solvothermal route. The intrinsic oxygen vacancies (OVs) in MoO3-x induce a local surface plasmon resonance (LSPR) effect, while Fe doping further refines the nanosheet dimensions (reducing the lateral size from ∼2 μm to ∼500 nm), and acts synergistically with the OVs to facilitate the separation and migration of photogenerated charge carriers. Photocatalytic tests reveal that under visible-light irradiation, the optimized 3-Fe-MoO3-x sample exhibits degradation efficiencies of 93.77% for methylene blue (MB) and 81.98% for tetracycline (TC), with reaction rates 1.99 and 2.11 times higher than those of undoped MoO3-x, respectively. The catalyst demonstrates moderate stability with slight deactivation, retaining approximately 84% of its initial activity for MB and 87% for TC after three consecutive cycles. Radical trapping experiments confirm that photogenerated holes (h+) and hydroxyl radicals (•OH) are the dominant active species driving the degradation of the target pollutants. This work elucidates the degradation pathways and mechanisms of MB and TC over LSPR-enhanced Fe-doped MoO3, offering valuable perspectives for the design of semiconductor photocatalysts in wastewater purification.