Hierarchical porous graphite-like carbon nanosheet cooperated with Fe/Fe3C@Fe-N-C nanocomposites toward catalytic oxidation process

Abstract

In this work, Fe, N co-doped hierarchical porous graphite-like carbon with carbon-encapsulated Fe/Fe3C@ Fe-N-C was synthesized by a facile solid-phase synthesis strategy, and was employed as an efficient catalyst to activate peroxymonosulfate (PMS) for oxidation of tetracycline (TC). The optimal Fe-N/C 800 outlined a highly catalytic performance in activating peroxymonosulfate (PMS) with TC decomposition rate reaching 89.2 % in 20 min at ultra-low catalyst dosage. Meanwhile, the effect of operating parameters was also investigated in order to evaluate the potential of using Fe-N/C 800 in practical applications. In addition, the characterization analysis and experiments results elucidated that graphitic N, pyridinic N, CO, Fe3C, Fe0 and FeN4 were considered as the main reactive species promoting the PMS activation to generate reactive oxygen species (ROS) (including singlet oxygen (1O2), sulfate radical (SO4•-) and hydroxyl radical (•OH)). The electron paramagnetic resonance (EPR) experiments and radicals quenching analyses further demonstrated that the non-radical species singlet oxygen (1O2) was the dominant reactive oxygen species. Moreover, the TC degradation pathways were presented by LC-MS. Ultimately, the toxicity of the intermediate products were also investigated by ECOSAR system.