Construction of BiOCl/MIL-121 Composites for Efficient Photodegradation of Organic Pollutants Under Visible Light Irradiation

The increasing discharge of organic pollutants such as dyes and antibiotics poses severe threats to aquatic ecosystems and human health. Conventional wastewater treatment methods are often limited by high energy consumption, secondary pollution, or low efficiency under visible light. It is crucial to design novel photocatalysts that can simultaneously utilize visible photons and enable swift transport of photoinduced charge carriers to drive contaminant decomposition. Herein, novel BiOCl/MIL-121 composites were synthesized via a straightforward hydrothermal route. A suite of complementary microscopic and spectroscopic analyses, including SEM, TEM, XRD and XPS, were employed to elucidate the material’s composition. Furthermore, collective evidence from spectroscopic and electrochemical analyses confirms markedly improved light absorption and charge separation efficiency within the BiOCl/MIL-121 photocatalyst. The 5% BiOCl/MIL-121 composite achieved 93.7% removal of Rhodamine B in 60 min, exhibiting a high photocatalytic degradation rate. Similarly, 5% BiOCl/MIL-121 photodegraded 80.4% of tetracyclin, which was much better than that of BiOCl. A plausible interfacial charge-transfer mechanism was deduced from the band structure of the 5% BiOCl/MIL-121 composite and experimental evidence from radical scavenger studies. This study provides an effective strategy for constructing a composite photocatalyst and offers a green way for the efficient degradation of organic pollutants.