Design of interfacial dual Schottky junctions to modulate charge transfer for enhanced piezo-assisted photocatalytic degradation RhB performances

Abstract

Regulating charge transfer is a great challenge for improving the efficiency of piezoelectric photocatalytic reactions. Herein, sandwich-like Bi₂WO₆@Ag/MXene nanoflower spheres (BWO@Ag/MXene) with piezoelectric/plasma dual characteristics were synthesized by a facile photoreduction method for photocatalytic applications. The charge migrations were driven by the built in polarization electric field and interfacial double Schottky junctions. The piezoelectric polarization electric field promoted the separation of photogenerated carriers, and the Schottky junctions boosted the interfacial charge transfer for the surface reactions. Moreover, the interface dual Schottky junction adjusted the bulk piezoelectric polarization field. The optimized BWO@Ag/MXene exhibited an amazing rate constant of up to 0.072 min⁻¹ for the degradation of rhodamine B under co-excitation of ultrasonic and visible light (λ > 380 nm) irradiation, which was 3.5 times higher than that of the pristine BWO sample. Piezoelectric force microscopy and COMSOL simulation showed the potential distribution and charge migration within BWO@Ag/MXene. This work provides a promising strategy for modulating charge migration toward enhancing photocatalytic efficiency with the assistance of mechanic vibration.