Enhancing Visible Light Photocatalytic Degradation of Bisphenol A Using BiOI/Bi₂MoO₆ Heterostructures

With the growing population, access to clean water is one of the 21st-century world's challenges. For this reason, different strategies to reduce pollutants in water using renewable energy sources should be exploited. Photocatalysts with extended visible light harvesting are an interesting route to degrade harmful molecules utilized in plastics, as is the case of Bisphenol A (BPA). This work uses a microwave-assisted route for the synthesis of two photocatalysts (BiOI and Bi₂MoO₆). Then, BiOI/Bi₂MoO₆ heterostructures of varied ratios were produced using the same synthetic routes. The BiOI/Bi₂MoO₆ with a flower-like shape exhibited high photocatalytic activity for BPA degradation compared to the individual BiOI and Bi₂MoO₆. The high photocatalytic activity was attributed to the matching electronic band structures and the interfacial contact between BiOI and Bi₂MoO₆, which could enhance the separation of photo-generated charges. Electrochemical, optical, structural, and chemical characterization demonstrated that it forms a BiOI/Bi₂MoO₆ p-n heterojunction. The free radical scavenging studies showed that superoxide radicals (O₂•^-) and holes (h⁺) were the main reactive species, while hydroxyl radical (•OH) generation was negligible during the photocatalytic degradation of BPA. The results can potentiate the application of the microwave synthesis of photocatalytic materials.