In-situ synthesis of Fe and O co-doped g-C₃N₄ to enhance peroxymonosulfate activation with favorable charge transfer for efficient contaminant decomposition

Iron and oxygen co-doped graphite phase carbon nitride (Fe@O[sbnd]CN) is synthesized via a simple one-pot in-situ pyrolysis method. It is used in a favorable peroxymonosulfate (PMS) activation oxidation system to enhance Orange I (OI) degradation. The effects of dopant contents, different water conditions and the reusability are conducted to evaluate the removal efficacy of PMS catalytic over Fe@O[sbnd]CN in water. Moreover, OI degradation is almost stable under several typical anions (H₂PO₄⁻, Cl⁻ and HCO₃⁻) and humic acid existence. Theoretical calculation results reveal that effective-directional transfer of electrons is obtained by Fe@O[sbnd]CN, building the formation of high electron density areas around Fe and O. The quenching tests display that O₂^•− and ¹O₂ are responsible for OI removal, and SO₄^•− and •OH only donate a very small contribution. The electron transfer between electron-rich Fe, O element and HSO₅⁻ cycles facilitate HSO₅⁻ activation to generate reactive oxygen species. After co-doping, DFT calculations confirm the stronger binding energy, greater charge transferability and longer O[sbnd]O bond length for PMS activation in Fe@O[sbnd]CN/PMS system. Our findings provide a valuable insight for the development of efficient catalysts for PMS activation via metal and nonmetal co-doping, which display a promising application for polluted aquatic environment.