The POM@MOF hybrid derived hierarchical hollow Mo/Co bimetal oxides nanocages for efficiently activating peroxymonosulfate to degrade levofloxacin.

Herein, we reported the design and fabrication of polyoxometalates coupling metal-organic framework (POM@MOF) hybrids derived hierarchical hollow Mo/Co bimetal oxides nanocages (Mo/Co HHBONs) for the peroxymonosulfate (PMS) activation to degrade levofloxacin (Lev). The Mo/Co HHBONs are hollow nanocages with high specific-surface areas and hierarchical micropores, mesopores, and macropores. In addition to compositional modulation, polyoxometalate (HPMoO·nHO) exhibited striking effect on the textural properties of Mo/Co HHBONs. The Mo/Co HHBONs had outstanding catalytic activity with first order-kinetics that were 6 - 10 times higher those previously reported. They exhibited good adaptability over a pH range of 3 - 11, as well as excellent universality and reusability. By altering the surface porosity, electronic structure, and oxygen vacancies of CoO, hetero-metal Mo doping induced Mo/Co HHBONs significantly promote the generation of reactive oxygen species, including OH, SO, O, and O. Density functional theory indicated that Mo/Co HHBONs had better adsorption, enhanced electron-transfer abilities, and a longer O-O bond length than did CoO, for improved catalytic reactivity. This research provides a new strategy to design the POM@MOF hybrids derived hierarchical hollow nanocages with highly PMS activating capacity for the removal of antibiotics and other refractory contaminants.