Mechanochemically constructed Bi2WO6/Zn-Al layered double hydroxide heterojunction with prominent visible light-driven photocatalytic efficiency

Layered double hydroxide (LDH) based heterojunction is a potential material for photodegradation of organic pollutants due to the high carrier separation efficiency, strong redox ability, and excellent mineral morphology features, while the conventional wet method for the fabrication of LDH-based heterojunction is a complicated process with potential secondary risks. In this paper, Bi2WO6/Zn-Al LDH heterostructures as highly effective photocatalysts were successfully fabricated by a facile two-step mechanochemical method. The phase composition, micromorphology, superficial chemical properties, optical utilization capability, and electrochemical characteristics of the as-prepared samples were tested, and the photocatalytic capacity was evaluated by degrading bisphenol A. With the inspired migration and restricted recombination of photogenerated carriers enabled by the heterostructure, Bi2WO6/LDH composites were found to exhibit greatly enhanced photocatalytic capacity compared to pristine Bi2WO6 and LDH. The energy band structure and transfer route for photogenerated charge carriers are discussed according to DFT calculations and ESR techniques, thereby illuminating the corresponding reaction mechanism for the photocatalysis process. With these results, this work provides a novel concept for the oriented design and facile fabrication of LDH-based heterostructures with high effectiveness.

Automated summary

In this work, Bi2WO6/Zn-Al LDH heterostructures were successfully fabricated as highly effective photocatalysts using a facile two-step mechanochemical method. The composites showed greatly enhanced photocatalytic capacity compared to pristine Bi2WO6 and LDH. The energy band structure and transfer route for photogenerated charge carriers were discussed, providing insights into the reaction mechanism for the photocatalysis process.