Nanocarbon materials are emerging as alternative activators of peroxymonosulfate (PMS) for organics decomposition. However, the relatively low activity and complex syntheses hindered their practical application and innovation with respect to rational design of carbocatalysts is highly desired. Herein, an in situ replication and transformation strategy was employed to facilely convert porous Fe3O4 microspheres into novel Fe/N codoped large-pore mesoporous carbon spheres (M‑Fe/NC) as Fenton-like catalysts for PMS activation. Benefiting from the abundance of active sites induced by dual heteroatom doping, the enhanced active site exposure due to the unique mesoporous structure, and the high stability of carbon component, the derived M‑Fe/NC was superior to the pristine Fe3O4 for PMS activation to degrade various organics and was efficient over a wide pH range (2-9). Compared with the proposed mechanisms of previous reports, both radical (surface-bound SO4- and OH) and nonradical (1O2 and direct oxidation) pathways are involved in the M‑Fe/NC/PMS system. Furthermore, experimental observations in combination with DFT calculations reveal that graphitic N and FeN4 sites serve as dual reaction centers in the catalysis. This research opened an avenue for development of novel multi-doped carbocatalysts used to activate PMS for sustainable remediation.
T. Zeng, Shuqi Li, Jianan Hua
The Science of the total environment