Nacre-Mimetic Structural Physical Encapsulation and Co-Mn Bimetallic Interaction for Stabilizing Cobalt Active Sites

The persistent challenge of antibiotic contamination in water necessitates efficient catalytic systems for peroxymonosulfate (PMS)-based advanced oxidation processes. While cobalt-based catalysts derived from ZIF-67 metal-organic frameworks and conventional core-shell structures like SiO 2 coatings offered limited physical encapsulation, they failed to prevent intra-particle agglomeration and adequately suppress Co ions leaching. Drawing inspiration from the dual-shell defense mechanism of the nacre structure, which combined physical and chemical mechanisms, this study constructed a Co 3 O 4 /C@MnSiO 3 (CCMS) nacre-mimetic nanostructured catalyst by converting the mesoporous SiO 2 on the surface of ZIF-67 into MnSiO 3 . The unique architecture effectively suppressed nanoparticle aggregation within individual ZIF-67 through physical encapsulation and bimetallic interaction, dispersed the active sites, reduced Co 2+ leaching, and enhanced catalytic activity. Compared to Co 3 O 4 /C (CC) and Co 3 O 4 /C@SiO 2 (CCS), the CCMS/PMS system significantly improved tetracycline degradation (1.4 and 2.3 times higher kinetic constants) and maintained 75% removal efficiency after five cycles. This study constructed a nacre-mimetic structure achieving highly efficient and stable catalysis, meanwhile providing novel strategies for optimizing MOF-based catalytic materials.