MOF-derived Mn₂O₃-decorated MoS₂-graphene composite for visible light-assisted degradation of environmentally hazardous penicillin G in water

A novel MOF-derived Mn2O3-decorated MoS2-graphene (MMG) composite was prepared via a facile hydrothermal method. The synthesized MMG composite was characterized through PXRD, FT-IR spectroscopy, DRS, TEM, FESEM, XPS and PL techniques. The prepared pure Mn2O3 exhibits a nano-chain-like agglomerated morphology with an average particle size of 50 nm distributed on the MoS2 and graphene layer as indicated by TEM images. DRS studies reveal a band gap of 1.22 eV for the MMG hybrid, demonstrating that the MMG hybrid can be used as a visible light-active photocatalyst. The study shows that the MMG-3 catalyst is excellent for the degradation of penicillin G under visible light with a rate constant (k(app)) of 1.1 x 10(-1) min. The photodegradation of PG by the MMG catalyst was found to be significantly faster than that by individual MSG or Mn2O3. The synergistic effect of MoS2 and graphene and a higher charge separation in the composite are major factors for a higher photocatalytic activity of the MMG catalyst. Moreover, the MMG catalyst exhibits good photostability, which ensures its potential applications in wastewater treatment and other energy applications. Finally, the photocatalytic mechanism of the MMG hybrid under visible light is presented after performing some radical scavenger tests.