Synthesis of parallel squared nanosheet-assembled Bi2WO6 microstructures under alkalescent hydrothermal treatment

The hierarchical Bi2WO6 microstructures, which were two-dimensionally assembled by parallel squared nanosheets, were synthesized under alkalescent hydrothermal treatment. The crystalline phase, morphology, size, lattice plane and crystalline structure of the products were characterized by X-ray diffraction, scanning/transmission electron microscopy and selected area electron diffraction. The formation of parallel squared nanosheet-assembled hierarchical Bi2WO6 microstructures was elucidated by the oriented attachment growth mechanism based on our experimental results. The aqueous ammonia, which was employed as the alkalescent environment, had a critical effect on the formation of such hierarchical Bi2WO6 microstructures with a large proportion of {001} facets. The parallel squared nanosheet-assembled hierarchical Bi2WO6 microstructures obtained at the hydrothermal temperature of 120 °C showed high photocatalytic activity under visible-light irradiation.