Investigation on Photo-Assisted Fenton-like Mechanism of Single-Atom Mn–N–Fe–N–Ni Charge Transfer Bridge Across Six-Membered Cavity of Graphitic Carbon Nitride

Abstract

Herein, Mn, Fe, and Ni single atoms are designed to be embedded into the six-membered cavity of the adjacent graphite phase carbon nitride layer, and the 2p orbitals of interlayer N atoms are hybridized with 3d orbitals of the Mn, Fe, and Ni single atom to form Mn–N–Fe–N–Ni charge transfer bridge throughout the six-membered cavity of the graphite phase carbon nitride. The DFT calculations provide a clear explanation for how the p–d orbital hybridization of Mn–N–Fe–N–Ni atoms facilitate the creation of a charge-transfer pathway. This pathway, which is located in the Mn–N–Fe–N–Ni charge-transfer bridge, serve as the catalyst for the degradation of oxytetracycline hydrochloride through photocatalysis. The photoatalytic activity is much higher than the graphite phase carbon nitride. The effects of the Mn–N–Fe–N–Ni charge transfer bridge on the migration of photogenerated carriers, photocatalytic degradation performance, and degradation mechanism are discussed in detail. In order to improve the degradation efficiency of oxytetracycline hydrochloride, the Mn–N–Fe–N–Ni charge-transfer bridge is utilized to activate peroxymonosulfate (PMS) under visible light exposure. The factors affecting the activation of PMS for oxytetracycline hydrochloride degradation are thoroughly investigated, and the degradation mechanism is also analyzed. This research contributes to a better comprehension of the photo-assisted Fenton-like effect of single-atom photocatalysts.