High-Efficiency Photo-Fenton-like Catalyst of FeOOH/g-C₃N₄ for the Degradation of PNP: Characterization, Catalytic...

The composite photocatalyst FeOOH/g-C₃N₄ was prepared through thermal polycondensation and co-precipitation methods, followed by XRD, SEM and UV-vis characterization. The stability of FeOOH/g-C₃N₄ was explored by the recycling test. The active species in the reaction system were investigated by the capture experiment. The results indicated that the optimal preparation condition for g-C₃N₄ involved calcination at 600 °C for 4 h. XRD analysis revealed that g-C₃N₄ exhibits a high-purity phase, and Fe in FeOOH/g-C₃N₄ exists in a highly dispersed amorphous state. SEM analysis showed that FeOOH/g-C₃N₄ has a rough surface with an irregular layered structure. Element composition analysis confirmed that the content of elements in the prepared catalyst is consistent with the theoretical calculation. FeOOH/g-C₃N₄ possesses the largest specific surface area of 143.2 m²/g and a suitable pore distribution. UV-vis DRS analysis showed that the absorption intensity of FeOOH/g-C₃N₄ is stronger than that of g-C₃N₄. When the catalyst dosage was 1.0 g/L, the H₂O₂ dosage was 4 mmol/L, the PNP initial concentration was 10 mg/L and the initial pH value was 5, the PNP removal could reach 92% in 120 min. Even after 5 cycles, the efficiency of PNP removal by FeOOH/g-C₃N₄ remains nearly 80%. The capture experiment indicated that both •OH and •O₂^- play roles in the photocatalytic degradation of PNP, with •OH being more significant. These findings affirm that FeOOH has been successfully incorporated into g-C₃N₄, resulting in a conspicuous catalytic effect on the degradation of PNP in the visible light-assisted Fenton-like reaction.