Synergistic effect of bimetal in three-dimensional hierarchical MnCo2O4 for high efficiency of photoinduced Fenton-like reaction

Bimetallic catalyst with three-dimensional hierarchical structure is very promising for Fenton-like reaction owing to its synergistic effect and unique microstructure. The combination of photocatalysis with peroxymonosulfate (PMS) as a good electron acceptor is an effective method to avoid the combination of electrons and holes, further significantly improving the degradation efficiency of refractory organics. In this work, a three-dimensional hierarchical and spinel-type MnCo2O4 catalyst was studied as a proof of concept for effective photoinduced PMS activation towards antibiotics degradation. As expected, the three-dimensional hierarchical MnCo2O4 (3D MnCo2O4) catalyst showed an excellent catalytic activity for PMS activation towards tetracycline (TC) degradation under the light irradiation over MnO2/light/PMS systems, Co3O4/light/PMS systems and general MnCo2O4/light/PMS systems. In a wide pH range (3-9) and a complex anionic (Cl−, HCO3−, NO3− and PO43−) environment, the 3D MnCo2O4/PMS/light system also can still degrade 95% of TC within 15 min and keep good catalytic stability. The superiority of 3D MnCo2O4/PMS/light system towards efficiency of TC degradation is attributed to its synergistic effect of Co-Mn on Co (III)/Co (II) cycle, peculiar microstructure and photocatalysis combination. Our work provides a promising highly-efficient heterogeneous catalytic system for environmental application.