Synergistic activation of persulfate by a manganese cobalt oxide/reduced graphene oxide nanocomposite with enhanced degradation of trichloroethylene

Abstract

Advanced oxidation technology based on persulfate is one of the most reliable and effective technologies for the degradation of wastewater, however the key lies in developing highly efficient catalysts to activate persulfate. Herein, manganese cobalt oxide/reduced graphene oxide (MnCo₂O₄/rGO) nanocomposites were successfully synthesized via a facile solvothermal method and employed as a highly efficient catalyst to active persulfate for the degradation of trichloroethylene (TCE). The rGO nanosheets have large surface areas, which can increase the contact area with reactants and make the degradation more efficient. Additionally, the MnCo₂O₄ nanoparticles are in situ grown on the surface of ultrathin rGO nanosheets, endowing the material with high structural porosity and fast transport channels, and are beneficial for the improvement of catalytic sites and the transport of catalysis-relevant species. More importantly, the close contact between MnCo₂O₄ nanoparticles and rGO nanosheets synergistically favors the electron transfer, thereby accelerating the electron transfer, improving the activation efficiency, and promoting the generation of sulfate radicals (·SO₄⁻). rGO can also reduce the spillover of metal ions. The kinetics model and degradation mechanism of the nanocomposites are also proposed.