Highly efficient sono-piezo-photo synergistic catalysis in bismuth layered ferroelectrics via finely distinguishing sonochemical and electromechanochemical processes

Ultrasonic stimulation induced polarization behaviors in ferroelectric materials have been extensively explored in catalytic degradations. However, the ultrasonic wave similarly can realize dye degradation by the sonocatalysis behavior, which is always neglected in most reports on in-situ ultrasound-induced piezoelectric catalysis, so that people might overestimate piezocatalytic contributions. For this, we designed a series of visible light sensitive bismuth layered ferroelectric materials (BLFMs), M0.5Bi2.5Nb2O9 (MBN, M = Li, Na, and K). It is found that the cavitation-induced degradation rates of Rhodamine B (RhB) strongly depend mechanical stirring speeds under a fixed ultrasonic power, which gradually increases with it, and reaches 77.9% (500 rpm and 3 h). Under lower stirring speed and reaction time (