MCM-41-supported Fe(Mn)/Cu bimetallic heterogeneous catalysis for enhanced and recyclable photo-Fenton degradation of methylene blue

Highly efficient bimetallic heterogeneous photo-Fenton catalysts (Fe2O3/CuO@MCM-41, FCM and MnOx/CuO@MCM-41, MCM) have been successfully prepared via wet impregnation over a mesoporous MCM-41 silica support. FESEM images demonstrate that the metal oxides are highly dispersed on the surface of the MCM-41 matrix consisting of the ordered 2D hexagonal mesostructure. XPS results indicate that the bimetallic oxides species in FCM and MCM are Fe2O3, CuO and MnOx, CuO, respectively. The as-prepared dual-heterojunctions have a significant enhancement of catalytic activities under visible light, compared with the material containing monometal, and prevents the leaching of metal ions species. The degradation efficiencies of MB can be up to 99.65% and 98.22% within 45 min irradiation for FCM1:2 and MCM1:0.5, respectively. And the degradation efficiencies still can reach up to 92% after 10 cycles. Moreover, the synthesized bimetallic dual-heterojunctions catalysts can be employed in very mild condition, and little difference in catalytic effect was observed under different pH value (3.0-9.0). The improved photocatalytic activity can be ascribed to the sufficient interfacial contact between different components for photo energy transfer and e(-)/h(+) pairs separation, which greatly enhance cycle reaction of Fe3+/Fe2+ or Mn4+/Mn3+/Mn2+ after introducing CuO. This research provides a new approach for the development of an effective heterogeneous photo-induced Fenton (Fenton like) catalyst with vast potential for organic pollutant removal.