Topochemical synthesis and photocatalytic activity of 3D hierarchical BaTiO₃ microspheres constructed from...

Novel BaTiO₃ hierarchical porous microspheres were achieved by using H₂Ti₂O₅·H₂O (HTO) hierarchical microspheres as a precursor template via a facile solvothermal method. Interestingly, the BaTiO₃ microspheres were constructed with two-dimensional (2D) nanosheets, which were composed of many order nanocrystals with crystal-axis-orientation. The special hierarchical structure, which is both macroporous and mesoporous, exhibits a large specific surface area and a high total pore volume. The photocatalytic performance of BaTiO₃ hierarchical microspheres for degradation of methyl orange (MO) under UV-light irradiation was tested, its apparent rate being up to 0.10183 min^-1, almost 23 times higher than that for nanoscale BaTiO₃ particles. The attractive photocatalytic properties are considered to benefit from the effective features of hierarchical BaTiO₃ microspheres, such as the ultrathin thickness of nanosheets and their ordered interconnected macro-mesoporous structure and intrinsic photocatalytic activity. This study offers an in situ topochemical conversion route to synthesis of other titanium-based perovskite hierarchical nanostructures, and thus opening the door for the synthesis of other titanium-based functional materials and expanding their potential application.