Greatly enhanced photocatalytic activity by organic flexible piezoelectric PVDF induced spatial electric field

Efficient charge separation accelerated by a spatial electric field is a vital factor for semiconductor photo-catalysts to achieve high photocatalytic activity. In this work, poly(vinylidene fluoride) (PVDF) with piezoelectric effects was first introduced into a photocatalyst system to highly improve the photocatalytic efficiency. The results indicate that, in the presence of organic piezoelectric PVDF, the photocatalytic efficiency of a PVDF-TiO2 film is improved by about 55%. The corresponding first-order reaction rate constant (k) value is increased 5.42 times. Moreover, photocatalytic activity enhancement is ascribed to the promotion effect of the spatial electric field on charge separation, which has been demonstrated by hydroxyl radical analysis. Furthermore, the results indicate that the spatial electric field of PVDF plays a generic enhancement role in the photocatalysis of both ultraviolet (UV)-light-responsive and visible-light-responsive photocatalysts. In a wider perspective, this work provides an efficient strategy, coupling solar energy and electric energy induced by organic flexible piezoelectric PVDF, to greatly enhance the photocatalytic performance.