Phthalocyanine pyrolysis derived Fe single-atom sites on g-C₃N₄ for enhanced photocatalytic organic pollutant degradation

The photocatalytic removal of organic pollutants from wastewater has gained significant attention in recent years due to its environmental benefits and cost-effectiveness. In this study, a pyrolytic iron phthalocyanine/graphitic carbon nitride (FePc/g-C 3 N 4 ) composite photocatalyst was synthesized using ball milling and thermal cracking, and its performance in photocatalytic degradation along with the underlying mechanisms was investigated. Under solar light irradiation, the pyrolytic FePc/g-C 3 N 4 photocatalyst achieved complete carbamazepine (CBZ) degradation within 12 min by activating peroxymonosulfate (PMS), demonstrating a 29 % enhancement in degradation efficiency compared to the unpyrolytic FePc/g-C 3 N 4 . Additionally, the stability of the catalyst improved significantly post-pyrolysis, maintaining over 98 % degradation efficiency across nine cycles. The thermal treatment disrupted the phthalocyanine structure, modifying the coordination environment of the central Fe atom and facilitating the transfer of photogenerated charge carriers. This research provides valuable insights for designing stable single-atom iron-based composite photocatalysts.