Complete defluorination of PFASs via photocatalytic reduction in water

The environmental persistence of per- and polyfluoroalkyl substances (PFASs), driven by the exceptional stability of their C-F bonds, presents a formidable challenge for remediation. Herein, we report the 5,10,15,20-tetraphenyl (4-aminophenyl) porphyrin (TAPP) aggregates as visible-light-driven photocatalysts capable of achieving almost-100% defluorination of PFASs without chemical additives. Central to this process is the ultra-stable TAPP radical species (TAPP^•), which exhibits a lifetime exceeding 7 days under ambient conditions. Under visible-light irradiation, TAPP^• generates reductive electrons with a potential of -2.68 V_NHE, enabling injection into the C-F antibonding orbitals to initiate defluorination. The exceptional stability of TAPP^• arises from intramolecular charge delocalization mediated by the synergistic overlap between the lone-pair electrons distribution of the amino groups and the highest occupied molecular orbital. This work develops a steady radical strategy that leverages charge-delocalization to engineer photocatalysts with highly reductive electron, offering an approach to address persistent environmental contaminants.