An Aqueous-Phased Synthesized CoMo-LDH Nanocage Activates Peroxymonosulfate for Tetracycline Degradation

Tetracycline (TC) is a widely used antibiotic and agricultural additive, which persists in aquatic environments and poses ecological risks. Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) provide promising solutions for the transformation of TC, but they require efficient catalysts. Here, we synthesized a hollow CoMo-LDH nanocage catalyst via in situ aqueous etching of ZIF-67, which is triggered by MoO₄^2-. This organic-solvent-free synthesis method effectively prevents secondary pollution. The CoMo-LDH/PMS system achieves 98.1% TC removal within 15 min and maintains 90.56% removal efficiency after 13 cycles. Mechanistic studies reveal that both radicals (^•OH/SO₄^•-) and the nonradical ¹O₂ pathway contribute to TC degradation, with ¹O₂ identified as the dominant reactive oxygen species (ROS). The Co(III)/Co(II) redox cycle drives PMS activation, which is particularly essential for the ¹O₂ generation. This work presents an eco-friendly strategy for fabricating stable, high-performance catalysts, which hold practical potential for water remediation.