Complete Reductive Defluorination of PFAS in Water Under Ambient Conditions via Plasmon-Enhanced Catalysis

Photo-driven, plasmon-enhanced catalysis enables high-efficiency PFAS degradation in water under ambient conditions. UV-induced localized surface plasmon resonance (LSPR) catalyzes complete reductive defluorination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), two legacy contaminants. Stable, quantum-sized palladium and platinum nanocatalysts supported on aminated mesoporous silica nanoparticles (MSN-NH2-Pd and MSN-NH2-Pt) rapidly transform PFOA and PFOS, with, or near, 100% stoichiometric defluorination under low-intensity UVC or UVA irradiation at room temperature. Time-resolved 19F NMR and high-resolution mass spectrometry, among other analyses, reveal a stepwise reductive hydrodefluorination pathway that proceeds without the formation of short-chain products, a major process advantage. Mechanistic studies identify hydrated electrons and in situ hydrogen generation as key reactive species, confirmed by scavenger and control experiments. Taken together, the approach harnesses synergistic interfacial PFAS sorption, plasmon-induced hydrogen evolution, and hydrated electron formation to enable a low-energy, scalable platform for sustainable PFAS treatment via complete defluorination.