Graphite carbon ring modified carbon nitride with a strong built-in electric field for high photocatalysis-self-Fenton performance

Abstract

The photocatalysis-self-Fenton is a novel technology for high-fluent degradation and high mineralization of aqueous organic pollutants. Herein, we constructed a novel photocatalysis-self-Fenton system in which graphite carbon (Cg) ring-doped graphitic carbon nitride (Cg-C₃N₄) serves as an active photocatalyst for the mineralization of pollutants and the generation of H₂O₂, and it combines with a Fenton agent to generate hydroxyl radicals. As a result, the degradation rate is 32.09 times higher than the reference photocatalysis, and the highest TOC removal efficiency of 59.64% is 11.36 times higher than that in the Fenton case. The incorporation of Cg rings modifies the π-electron delocalization in the conjugated system of Cg-C₃N₄ and thus exhibits a more positive valence band position (+2.20 eV) and a wider photo-response range. Importantly, introducing the built-in electric field (IEF) in Cg-C₃N₄ induced by Cg rings enhances the separation of photogenerated charge, thereby improving the photoelectric ability to H₂O₂ and accelerating the cycle of Fe²⁺/Fe³⁺ to facilitate the conversion of H₂O₂ to ˙OH.