Unraveling the discriminative mechanisms for peroxy activation via atomically dispersed Fe-N5 sites for tunable water decontamination

The discriminative activities and mechanisms for activation of O-O bond in peroxy compounds via single-atom catalysts (SACs) especially with a higher coordination number (M-N 5 ) are rarely explored. Herein, the atomic catalyst (Fe-SAC) with Fe-N 5 as the active center was constructed, which could simultaneously and effectively activate peroxymonosulfate (PMS), peroxydisulfate (PDS), and hydrogen peroxide (H 2 O 2 ). Density functional theory (DFT) calculations combined with experiments results demonstrated that the degradation efficiencies of acyclovir were corresponding to the changes of O-O bond length in various peroxy compounds. Meanwhile, the experiments exposed that the three oxidants all produced • OH, but the PMS also contained 1 O 2 and Fe(IV)=O, and PDS contained O 2 •- additively. The scale-up experiment showed Fe-SAC could operate steadily for nearly 7 d. Overall, this work unveils the discriminative mechanisms for activation of O-O band in different Fenton-like systems. Moreover, the Fe-SAC with high coordination numbers has excellent catalytic properties and practical performance.