Topochemical synthesis and photocatalytic activity of 3D hierarchical BaTiO 3 microspheres constructed from crystal-axis-oriented nanosheets

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.