Ultrasound-driven ferroelectric polarization of TiO2/Bi0.5Na0.5TiO3 heterojunctions for improved sonocatalytic activity

Herein, a series of TiO 2 /Bi 0.5 Na 0.5 TiO 3 heterojunctions with different mass ratio are first constructed under ultrasound irradiation, which shows superior sonocatalytic and photoelectrochemical properties. The improved performance is attributed to the internal electric field and close interfacial contact of TiO 2 and Bi 0.5 Na 0.5 TiO 3 , which promote the transfer of photoinduced electrons from TiO 2 to Bi 0.5 Na 0.5 TiO 3 . The spontaneous polarization of ferroelectrics in the heterostructures can be adjusted by ultrasonic treatment durations, which further influences the internal electric field. The TiO 2 /Bi 0.5 Na 0.5 TiO 3 sample with mass ratios of 5:1 and ultrasonic treatment for 15 min presents the highest sonocatalytic degradation of Rhodamine B. Moreover, the sonocatalytic activity also shows a close relevant to the ultrasonic temperature and frequency of degradation process. And, the •OH radicals are mainly responsible for Rhodamine B sonodegradation. This work provides a novel TiO 2 /Bi 0.5 Na 0.5 TiO 3 heterojunctions and promotes the application of ferroelectrics modified materials in sono-/photo-catalysis.