Identifying the Synergistic Role of Graphitic Nitrogen and Cobalt Nanoparticle in Electron Transfer Pathway Toward Fenton‐Like Catalysis

ABSTRACT Cobalt and nitrogen co‐doped catalysts have been widely reported in Fenton‐like processes for water decontamination. However, there is not yet clear how the interaction between cobalt and nitrogen regulates the non‐radical electron transfer mechanism. Here, a carbon nanotube (CNT) catalyst (CoN/C‐8) containing nitrogen element and a beads‐on‐string cobalt nanoparticles (Co NPs) was synthesized to utilize peroxymonosulfate (PMS). The CoN/C‐8/PMS process exhibited excellent stability and reusability for water treatment, maintaining above 95% of tetracycline hydrochloride (TCH) removal under a continuous‐flow operation of 600 min. A series of electrochemical tests, COMSOL multiphysics simulations, and density functional theory calculations collectively elucidate an electron transfer pathway from TCH to the complex of catalyst and PMS (PMS*) and the synergistic effect of graphitic N (Grap‐N) and Co NPs during the CoN/C‐8/PMS process. Interestingly, although the total number of electrons from the catalyst to PMS increases after the Grap‐N interface covering the Co NPs, the main electron donor shifts from the Co NPs to the Grap‐N‐containing carbon layer interface. These results suggest that the Grap‐N interface as an electron transfer highway could protect the easily deactivated cobalt nanoparticles and effectively enhance the stability and life of the catalyst, thus providing valuable guidance for water decontamination.