Simultaneously accelerating the regeneration of FeII and the selectivity of 2e- oxygen reduction over sulfide iron-based carbon aerogel in electro-Fenton system

The regeneration of surface Fe II and the electro-formation of H 2 O 2 play crucial roles for determining the degradation efficiency of heterogeneous electro-Fenton process. The sulfide iron-based carbon aerogel was synthesized directly as cathode. The main composition of iron compounds were Fe 3 O 4 and FeS∙FeS 2 , which were embedded in the matrix of carbon aerogels. Most of sulfur was evenly distributed on carbon, favoring the formation of −COOH groups. The nature of existed sulfur were investigated by temperature-programmed reaction spectroscopy respectively under the CO 2 and air. The S-doping promoted the regeneration of Fe II and improved the selectivity of 2e − oxygen reduction with iron-based carbon materials. As high as 99 % removal of dimethyl phthalate and 3-chlorophenol were obtained in 240 min. Meanwhile, the EPR results demonstrated that HO∙ was formed by on site decomposing H 2 O 2 with FeSCA, which exhibited high stability with low Fe leaching (< 2 ppm) and high recyclability even in acidic medium.