Oxygen-Deficient Petal-Like MoO3–x Nanosheets for Efficient Visible-Light Photocatalytic Degradation of Methylene Blue and Broad-Spectrum Pollutant Removal

Defect engineering, particularly the creation of oxygen vacancies (Ovs), has emerged as a transformative strategy for enhancing the photocatalytic efficacy of metal oxides. Herein, we report petal-like MoO 3– x nanostructures engineered with abundant Ovs via a precisely controlled solvothermal method. Compared with previously reported MoO 3 photocatalysts, the engineered Ovs significantly narrow the bandgap from 3.12 to 3.02 eV, endowing the material with exceptional visible-light absorption capacity. Under visible-light irradiation, the samples exhibit a 2.68-fold higher degradation efficiency toward methylene blue (MB), achieving 98.85% removal within 240 min. Reaction kinetics and radical trapping experiments collectively demonstrate that pollutant degradation proceeds via a synergistic mechanism involving efficient adsorption and oxidative pathways dominated by photogenerated holes (h + ) and hydroxyl radicals (•OH). Moreover, the as-prepared MoO 3– x also exhibits favorable photocatalytic activities toward tetracycline hydrochloride (TCH) degradation and Cr(VI) reduction, demonstrating its broad-spectrum application potential for environmental remediation. Mechanistic insights reveal that the introduced Ovs in MoO 3– x nanosheets function synergistically in three key aspects: broadening visible-light harvesting, acting as electron traps to inhibit carrier recombination, and promoting substrate adsorption. This work elucidates the integrated functions of Ovs in modulating electronic structure and interfacial processes, offering a transferable design strategy for developing advanced photocatalytic materials.