Ultrasonic bath synthesized MIL-88B(Fe)/AgCl/Ag composite for visible-light photocatalytic degradation of anthracene

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic pollutants commonly detected in fine particulate matter (PM2.5), posing significant risks to environmental and human health. In this study, a visible light active composite photocatalyst, MIL-88B(Fe)/AgCl/Ag, was synthesized via a precipitation method followed by photoreduction to enhance the photocatalytic performance of MIL-88B(Fe) for anthracene degradation. The ternary composite exhibited significantly improved photocatalytic activity compared with pristine MIL-88B(Fe) and AgCl/Ag under visible-light irradiation, which is attributed to the formation of an efficient heterojunction that promotes charge separation and reactive species generation. Scavenger experiments and electron paramagnetic resonance (EPR) spectroscopy revealed that singlet oxygen (¹O₂) is the dominant reactive species, while hydroxyl radicals (^•OH) play a secondary role in the degradation process. Product analysis using UV-vis spectroscopy and GC-MS confirmed that anthracene is initially oxidized to 9,10-anthraquinone through ¹O₂ and ^•OH. Further photochemical reactions lead to smaller aromatic products such as benzaldehyde, benzyl alcohol, and their methylated derivatives. The synergistic interaction between Ag/AgCl and MIL-88B(Fe) enables dual oxidation pathways and promotes charge separation, resulting in enhanced photocatalytic efficiency. These findings provide insight into the photocatalytic degradation pathways of anthracene and suggest the potential of MOF-based composite photocatalysts for visible-light-driven environmental remediation.