BaTiO Nanosheets and Caps Grown on TiO Nanorod Arrays as Thin-Film Catalysts for Piezocatalytic Applications.

Powder-form piezocatalysts suffer from poor recyclability and pose a potential threat of creating serious secondary pollution, which restrict their practical applications. Thin-film piezocatalysts, which not only exhibit good recyclability but also fully contact with solution, are believed to be one of the solutions to address these problems. In this work, the nanostructured BaTiO (BTO) thin films were fabricated by a facile hydrothermal method for their potential applications in piezocatalysis. The vertically standing BTO nanosheets grown on the top of TiO nanorod arrays exhibited superior piezocatalytic performance as well as piezo-electrochemical property. Given the different strain states between thin-film piezocatalyst and powder-form piezocatalyst, both the impact force of water and isostatic pressure are taken into consideration in finite element method (FEM) simulation. The FEM simulation shows that a stronger piezoelectric filed can be built in BTO nanosheets because of their easier deformation, and thus can lead to a higher piezocatalytic degradation efficiency. Our work presented here is expected to provide a potential route for the nanoengineering of thin-film piezocatalysts and clarify the catalytic mechanism for substrate-fixed piezocatalysts.