Engineered carbon supported single iron atom sites and iron clusters from Fe-rich Enteromorpha for Fenton-like reactions via nonradical pathways

Enteromorpha as a seawater pollutant was innovatively converted into a functional carbocatalyst to driven Fenton-like reactions.After direct pyrolysis of Enteromorpha at 900 °C without additional chemicals, a large number of Fe clusters and single Fe sites are anchored onto N-doped carbon matrixes ( Enteromorpha -derived Fe-N-C) with a high Fe loading of 0.84 wt.%. The Enteromorpha -derived Fe-N-C exhibits a high activity in the heterogeneous activation of peroxymonosulfate (PMS) for organic pollutant degradation. Radical quenching experiments and electrochemical analysis tests verify the nonradical oxidation by high-valence iron-oxo species and an electron-transfer pathway. The single Fe atoms, which only accounted for the minority of the Fe species in Fe-N-C, acted as the dominated reactive sites for the formation of highly oxidizing Fe IV =O and Fe V =O sites. This work unveils the evolution of bio-Fe in Enteromorpha during thermal pyrolysis and the role of the derived Fe-N-C in PMS activation and organic degradation.