Insight into the selective oxidation behavior of organic pollutants via Ni-N4-C mediated electron transfer pathway

Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) is a hopeful method for organic pollutants degradation. However, conventional AOPs often suffer from various disturbances in applications, such as organic matter, inorganic ions, pH, etc. Herein, a novel Ni(Ⅱ)-doped g-C3N4 (Ni4.60CN) catalyst with Ni-N4-C structure was prepared, which exhibited outstanding PMS activation ability. The Ni-N4-C active sites facilitated the electron transfer from pollutants to PMS and achieving high selectivity toward pollutant degradation. Then, integrating experimental and theoretical results, the origin of this selectivity was revealed, indicating that organic pollutants with low vertical ionization potential (VIP), high the highest occupied molecular orbital energy (EHOMO), and low potential differences between organics and Ni4.60CN (marked as EPD) are more beneficial to be degraded. This study unravels the electron transfer mechanism induced by Ni-N4-C sites in Ni4.60CN /PMS activation system and provides a comprehensive insight into the selective oxidation behavior of various pollutants.