Synergistically enhancing Fenton-like degradation of organics by in situ transformation from Fe3O4 microspheres to mesoporous Fe, N-dual doped carbon

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 center dot(-) and center dot OH) and nonradical (O-1(2) and direct oxidation) pathways are involved in the MFe/NC/PMS system. Furthermore, experimental observations in combination with DFT calculations reveal that graphitic N and Fe-N-4 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. (C) 2018 Elsevier B.V. All rights reserved.