Z-scheme ZnFe2O4/MoO3 composite as efficient peroxymonosulfate activator under visible light for enrofloxacin degradation.

The photocatalytic degradation of pollutants in water remains a significant challenge due to the rapid recombination of photogenerated electron-hole pairs, which hinders photocatalytic efficiency. To address this issue, we successfully constructed a Z-scheme ZnFe2O4/MoO3 composite to activate peroxymonosulfate (PMS) for the efficient degradation of enrofloxacin (ENR) under visible light. By constructing a Z-scheme heterojunction, we significantly improved the average lifetime of photogenerated carriers and effectively enhanced the separation efficiency of e-/h+ pairs. Activating PMS under visible light improved the generation and stability of reactive species in the system, thereby enhancing the degradation efficiency of ENR. Under optimal conditions, the ZnFe2O4/MoO3/Vis/PMS system achieved over 75 % ENR degradation efficiency, even in the presence of various interfering ions such as Cl-, NO3-, HCO3-, and humic acid (HA). Furthermore, radical quenching experiments and electron paramagnetic resonance (EPR) analysis confirmed h+ and 1O2 as the predominant reactive species. Additionally, density functional theory (DFT) calculations were performed to provide insights into the electronic structure and band alignment of the ZnFe2O4/MoO3 composite, offering theoretical support for understanding its charge separation and transfer mechanisms. This work not only provides new insights into the photocatalytic degradation of pollutants in water but also elucidates the synergistic effect between photocatalysis and PMS activation for pollutant degradation.