A synchronous defluorination-oxidation process for efficient mineralization of fluoroarenes with photoelectrocatalysis

Abstract

Fluoroarene (FA) derivatives are persistent, toxic, and bioaccumulative pollutants, which pose severe risks to ecosystems and human health. Efficient cleavage of C–F bonds and complete mineralization of defluorinated intermediates are the keys for the deep treatment of FAs due to the high dissociation energy of C–F bonds and the high stability of aromatic rings. Herein, we report a synchronous defluorination-oxidation process using a photoelectrocatalytic device with a TiO2 photoanode, in which FAs are selectively cleavage of C–F bonds by photolysis and subsequently efficient oxidized by on-site generated •OH radical. Complete defluorination and mineralization (both over 99.9%) of 4-fluorophenol are achieved under irradiation at 1.0 VRHE in 120 min, the apparent reaction rate constant is 14.4 g h−1 m−2. This synchronous defluorination-oxidation process provides an efficient and practical technique for the mineralization of FAs in wastewater under mild conditions.