Turbulence enhanced ferroelectric-nanocrystal-based photocatalysis in urchin-like TiO2/BaTiO3 microspheres for hydrogen evolution

Abstract

The application of a built-in electric field due to piezoelectric potential is one of the most efficient approaches for photo-induced charge transport and separation. However, the efficiency of converting mechanical energy to chemical energy is still very low, and the enhancement of photocatalysis, thus, is limited. To overcome this problem, here, we propose sonophotocatalysis based on a new hybrid photocatalyst, which combines ferroelectric nanocrystals (BaTiO₃) and dendritic TiO₂ to form an urchin-like TiO₂/BaTiO₃ hybrid photocatalyst. Under periodic ultrasonic excitation, a spontaneous polarization potential of BaTiO₃ nanocrystals in response to ultrasonic waves can act as an alternating built-in electric field to separate photoinduced carriers incessantly, which can significantly enhance the photocatalytic activity and cyclic performance of the urchin-like TiO₂/BaTiO₃ catalyst. More importantly, the significant enhancement of photocatalytic hydrogen evolution is due to the coupling effect of two types of piezoelectric potential in the presence of BaTiO₃ nanocubes as well as the semiconductor and optical properties of TiO₂ nanowires of the urchin-like TiO₂/BaTiO₃ hybrid structure under simulated sunlight and periodic ultrasonic irradiation, which can significantly improve the efficiency of converting mechanical energy to chemical energy.