Selective recognition and activation for accelerated decarboxylation and C–F bond cleavage of perfluorooctanoic acid

Perfluorooctanoic acid (PFOA), a synthetic persistent and bio-accumulative chemical, has raised global concerns. PFOA oxidation by advanced oxidation technology (AOPs) begins with decarboxylation, followed by CF 2 groups unzipping cycle and C–F cleavage. Since reactive radicals (even •OH) cannot initiate decarboxylation and abundant low-toxicity organics hinders decarboxylation, presents significant challenges for defluorination. We designed a functionalized high-index (201) TiO 2 photoanode (S-TiO 2,201 ) capable of molecular recognition and activation, which switches PFOA adsorption from carboxyl groups to preferential adsorption via the perfluoroalkyl backbone. This adsorption configuration selectively recognizes PFOA and accelerates decarboxylation via direct hole oxidation. In situ electron paramagnetic resonance (EPR) confirmed faster decarboxylation and •OH quantification showed hole utilization efficiency rising from 9.6 % to 39.3 % after functionalization. PFOA was selectively removed from 200 μg/L to 1.2 μg/L with 1000-fold humic acid interference. This work presents a strategy for efficient and selective PFOA removal by precisely modulating its adsorption configuration.