Edge-Hosted Graphitic Nitrogen Sites Carbocatalysts Mediated Electron Transfer Process for Powerful Fenton-Like Reactions

The nonradical electron transfer process (ETP) without the preliminary decomposition of peroxymonosulfate (PMS) contributes to a green and sustainable water treatment. Moreover, the target regulation of ETP in PMS-based Fenton-like reactions has important practical significance, and the corresponding mechanism still needs to be further clarified. Here, by introducing edge-hosted graphitic nitrogen sites into carbocatalysts (E-gNC), we demonstrate the first achievement in subjectively regulating ETP via microenvironment engineering of active sites. The E-gNC exerts a highly efficient performance for phenol degradation via an ETP regime, while its counterpart with abundant pyridinic nitrogen sites (pNC) produces multiple reactive oxygen species (ROSs). The turnover frequency (TOF) of E-gNC (5.38) is about 20 times that of pNC (0.27), and its degradation rate is also superior to those of most reported carbocatalysts. In situ spectra and theoretical simulations reveal that the electricity-deficient edge-hosted graphitic N sites and their neighbor C sites can simultaneously adsorb the Oβ and S atoms of PMS, respectively, facilitating the formation of metastable E-gNC-PMS* active complex rather than the decomposition of PMS. Compared with the traditional methods of premixed PMS and pollution, the E-gNC/PMS system can save about 45% of PMS, demonstrating great potential for practical application. This work reveals the intrinsic mechanism by which the microenvironment of N sites influences PMS-based Fenton-like reactions at the atomic level, paving avenues for new vitality of this ancient material in water treatment.