Synthesis of Bi_2WO_6 hierarchical structures constructed by porous nanoplates and their associated photocatalytic properties under visible light irradiation

摘要

We report a facile template-free solvothermal approach for the synthesis of Bi_2WO_6 hierarchical structures assembled by porous nanoplates, the unique morphology of which endows the sample with high photocatalytic activity under visible light irradiation. The synthesized Bi_2WO_6 hierarchical structures have diameters of ~ 1 μm, and consist of multiple crossed-plates in three-dimensional configuration. A possible three-stage formation mechanism was proposed for the construction of hierarchical structures, and Ostwald ripening was responsible for the formation of meso-pores. The as-prepared Bi_2WO_6 hierarchical structures exhibited high photocatalytic activity on the degradation of Rhodamine B under visible light irradiation, due to the larger specific surface area (20.4 m~2 g~(-1)), unique hierarchical structures with multiple-crossed porous layer and higher crystallinity. A comparison of photocatalytic performance between the hierarchical structures and other samples with different morphologies was performed. The main active species of Bi_2WO_6 hierarchical structures during a photocatalytic process were determined to be·O~(2-) and h~+ radicals by dissolving different trapping agents.