Enhanced photocatalytic activity and cycle stability driven by ultrasonic vibration for ferroelectric photocatalysts

Abstract

Ferroelectric materials have been applied in the photocatalytic field due to the internal electric field generated by the spontaneous polarisation. In this study, it is found that the ferroelectric BaTiO 3 catalysts exhibit the excellent photocatalytic property and cycle stability under ultrasonic vibration. In addition, the degraded photocatalytic activity after several cycling tests can resurrect if the BaTiO 3 sample is treated by ultrasonic before photocatalytic reaction. The enhanced photocatalytic activity and cycle stability are ascribed to the variational spontaneous polarisation under external strain for ferroelectric materials. Under ultrasonic vibration, the high-frequency alternating strain applied on the BaTiO 3 grain changes the internal polarisation electric field. Due to the fast changing polarisation electric field, there is no enough time to form the depolarisation electric field in the BaTiO 3 grain. Therefore, the effective electric field existed in BaTiO 3 grain is large and can effectively promote the separation the photo-generated electrons/holes; thus improving the photocatalytic activity. It is suggested that ultrasonic vibration is an efficient method to improve the photocatalytic properties and cycle stability of the ferroelectric photocatalysts.