Efficient electro-Fenton degradation of organic pollutants via the synergistic effect of O and OH generated on single FeN sites.

The electro-Fenton with in situ generated O and OH is a promising method for the degradation of micropollutants. However, its application is hindered by the lack of catalysts that can efficiently generate O and OH from electrochemical oxygen reduction. Herein, N-doped stacked carbon nanosheets supported Fe single atoms (Fe-NSC) with FeN sites were designed for simultaneous generation of O and OH to enhance electro-Fenton degradation. Due to the synergistic effect of O and OH, a variety of contaminants (phenol, 2,4-dichlorophenol, sulfamethoxazole, atrazine and bisphenol A) were efficiently degraded with high kinetic constants of 0.037-0.071 min by the electro-Fenton with Fe-NSC as cathode (-0.6 V vs Ag/AgCl, pH 6). Moreover, the superior performance for electro-Fenton degradation was well maintained in a wide pH range from 3 to 10 even with interference of various inorganic salt ions. It was found that FeN sites with pyridinic N coordination were responsible for its good performance for electro-Fenton degradation. Its O yield was higher than OH yield, and the contribution of O was more significant than OH for pollutant degradation.