3d Hierarchical Porous Nico-Spinel Nanosheet Array Synergistic Activation of Peroxymonosulfate for Tetracycline Degradation: The Critical Role of Nonradical Mechanism

The rational design of bimetallic-based heterogeneous Fenton-like catalyst derived from metal-organic-frameworks (MOFs) for peroxymonosulfate (PMS) activation via a non-radical pathway is attractive but challenging. Herein, a spinel-type 3D hierarchical porous NiCo2O4 nanosheet array for the activation of PMS is rationally designed by surfactant-assisted interfacial engineering. The NiCo2O4/PMS system demonstrated remarkable oxidative degradation of tetracycline (TC) through 1O2 attack and electron transfer process, which was different from previous reports where the free radicals also play a role in the degradation. The synergy between surface Co and Ni enhances electron transfer efficiency and peroxyl bond cleavage, laying the foundation for subsequent radical conversion to 1O2, which was the dominant catalytic mechanism. The system also possessed a broad spectrum for degrading other typical contaminants, and maintained decent degradation performance in actual water matrix, wide pH range and in the presence of anions and organic matter. Furthermore, the robust stability of the structure and catalytic activity make it promising for practical water treatment. It can be expected that this proposal will provide insights for the delicate structural design and the understanding of its PMS activation mechanism of bimetallic-based Fenton-like catalysts, as well as for the efficient degradation of emerging organic pollutants.