High-efficiency PMS activation by difunctional Co-Fe PBA/g-C3N4 S-scheme heterojunction for oxytetracycline degradation: Performance evaluation and mechanism insight

The utilization of sulfate radical-based advanced oxidation processes (SR-AOPs) has captivated the academic community due to their minimal energy requirements and superior efficacy in peroxomonosulfate (PMS) activation for pollutant decomposition. Notwithstanding these advantages, engineering an effective and economical catalyst for PMS activation presents a considerable hurdle. In the present study, a metal-organic framework of CoFe PBA is ingeniously anchored onto g-C₃N₄ nanosheets, resulting in the formation of an innovative CoFe PBA/g-C₃N₄ S-scheme heterojunction that demonstrates remarkable efficiency in PMS activation. Intriguingly, the catalytic efficiency of CoFe PBA/g-C₃N₄ surpasses that of g-C₃N₄ and CoFe PBA by 7-fold and 2.33-fold, respectively. The heightened activity of CoFe PBA/g-C₃N₄ heterojunction is attributed to the enhanced charge transfer efficiency, a consequence of the successful heterojunction formation. Concurrently, the ability of photoexcited electrons to reduce Co³⁺/Fe³⁺ to Co²⁺/Fe²⁺ bolsters PMS activation. Significantly, this heterojunction retains unparalleled stability in degrading oxytetracycline without discernible performance attenuation, heralding its commendable prospects in real-world applications. Besides, mechanism exploration indicates that SO₄^-, h⁺, and electron transfer contribute to oxytetracycline degradation in the CoFe PBA/g-C₃N₄ system. This investigation serves as a beacon for the strategic development of highly active and stable catalysts for PMS activation, aiming at environmental decontamination.