Self-restoration of reactive centers via contaminant-to-catalyst electron replenishment for sustained Fenton-like activity

The challenge of achieving self-driven restoration of catalytic sites without external energy or chemical input is critical, which can extend the service life of the catalyst and efficiently reduce water treatment costs. Herein, we fabricate high-spin Mo2+ doped FeS2 catalysts to realize efficient peroxymonosulfate (PMS) activation and contaminant degradation. Notably, doped high-spin Mo2+ can spontaneously enrich contaminants and extract electrons from electron-rich contaminants owing to the active 4 d orbital, which replenishes electrons consumed by high-spin Fe during PMS activation. This “contaminant-to-catalyst” electron replenishment pathway, driven primarily by high-spin Mo2+ and synergistically assisted by lattice S, accomplishes the sustainable restoration of reactive centers. Consequently, ~800 mg of 0.39 wt% Mo-FeS2 maintains high activity for over 15 days in a continuous-flow reactor, which treats 216 L of bisphenol A-containing wastewater, surpassing most of reported Fenton-like systems. Ab initio molecular dynamics simulations reveal the interfacial radical oxidation mediated by proton-coupled electron transfer, reducing the migration of radicals and enhancing the mineralization of contaminants. Furthermore, we establish a scalable synthesis for producing kilogram-scale catalyst, immobilizing onto sponges for realizing the selective elimination of trace emerging contaminants from four types of municipal wastewater. Overall, this work provides a promising strategy for developing durable Fenton-like catalysts. In this study, high-spin Mo2+ species in FeS2 mediate a “contaminant-to-catalyst” electron replenishment pathway to enable active-site restoration, allowing contaminants to function beyond their conventional role as degradation targets.