MOF-Derived Entropy-Stabilized Quinary Alloy@Cellulose Aerogel for Ultrafast Tetracycline Degradation via PMS Activation.

The persistent contamination of aquatic ecosystems by recalcitrant tetracycline antibiotics demands advanced catalytic systems beyond conventional oxidation methods. Here, a sustainable high-entropy catalyst, FeMnCoZnCu@NCNP@CA is reported, comprising MOF-derived multi-metallic nanoparticles confined within a nitrogen-doped carbon matrix and anchored on a 3D cellulose aerogel scaffold. The hybrid is obtained by pyrolyzing a quinary FeMnCoZnCu-NTA MOF precursor. This hierarchical design integrates several key features: high-entropy stabilization to suppress phase segregation, N-doping-driven charge redistribution to enhance conductivity and active-site density and multivalent redox coupling to promote reactive oxygen species generation (SO4•-, •OH, 1O2) and accelerate electron transfer. The confined carbon matrix effectively minimizes metal leaching (<0.1 ppm), while the aerogel macroporosity ensures rapid diffusion and enables >85% catalyst recovery. Under optimal conditions ([Catalyst] = 0.25 g L- 1, [PMS] = 0.31 g L- 1, pH = 3), FeMnCoZnCu@NCNP@CA achieves >98% tetracycline degradation within 15 min, exhibiting a rate constant (k = 0.070 ± 0.013 min- 1) that is 4.2 times higher than the mono-metallic Fe@NCNP and surpasses di-, tri- and tetra-metallic analogues. This work highlights MOF-derived high-entropy hybrids as a promising platform for antibiotic remediation through the synergistic integration of multi-metallic entropy, nitrogen doping, structural confinement and biomass aerogel engineering.