High-entropy engineering of spinel catalysts for nonradical catalytic ozonation with improved resistance to humidity and sulfur poisoning

Conventional catalytic ozonation of electron-rich sulfur-containing pollutants shows limited efficiency due to nonselective oxidation of hydroxyl radicals ( • OH) and sulfate-induced deactivation of active metal sites. Here, we synthesized a high-entropy spinel, (CuNiMnCo)Fe 2 O 4 , featuring sublattice-resolved electronic reconstruction that enables selective ozone activation and suppresses sulfur poisoning. The catalyst achieves 99% removal of methyl mercaptan (CH 3 SH), significantly outperforming 51% of CoFe 2 O 4 . Spectroscopic analyses and density functional theory calculations reveal that high-entropy doping induces lattice distortion and local coordination disorder, which strengthen A–O–B covalency and inter-site electronic communication. This structural perturbation further drives a sublattice-resolved electronic reconstruction, enriching Co/Mn sites while depleting Fe/Cu/Ni sites. This electronic differentiation promotes cooperative dual-end activation of O 3 on Fe–Co/Mn motifs and preferential CH 3 SH adsorption on Cu/Ni sites. Orbital modulation of Co t 2g and Fe e g states near the Fermi level balances interfacial charge transfer, favoring formation of a surface-bound *O 3 species over conventional O–O bond cleavage. The resulting spatially separated activation and oxidation sites enable CH 3 SH mineralization via an electron transfer process while suppressing • OH generation and minimizing sulfate accumulation. This spatially differentiated reaction environment ensures durable performance under humid conditions. These findings establish sublattice-engineered electronic asymmetry as a strategy for selective catalytic ozonation.