Melamine-cyanurate supramolecule induced graphitic N-rich graphene for singlet oxygen-dominated peroxymonosulfate activation to efficiently degrade organic pollutants

Abstract

Graphitic N-rich graphene (GNG) was prepared through a melamine-cyanurate (MC) supramolecule induced method by pyrolyzing the precursor of graphene oxide@melamine cyanurate composite (GO@MC). The fabricated sample at 800 °C (GNG8) possessed the high graphitic N content of 4.18%, which exhibited excellent capability to peroxymonosulfate (PMS) activation for degradation of organic pollutants. Results of electron paramagnetic resonance (EPR) spectra coupled with quenching experiments and density functional theory (DFT) calculations revealed that the graphitic N in graphene was the intrinsic active site for the cleavage of O-O bond in PMS to produce singlet-oxygen (1O2), responsible for organics degradation. Furthermore, the GNG/PMS system could work in a wide temperature range (5–45 °C), and the common matrix species of Cl−, NO3−, HCO3− and HA had negligible effect on the degradation performance. This study provided a facile strategy for the preparation of highly graphitic N doped graphene catalysts to powerfully degrade organic pollutants, and deep understand of the catalytic mechanism of GNG for PMS activation.