Z-Scheme Cdin2s4/Bi2wo6 Heterojunction for Highly Efficient Piezo-Photo Synergetic Performance

The piezoelectric effect triggered by mechanical energy can establish internal electric field and effectively modulate the separation behavior of carriers. Here, we construct a Z-scheme CdIn2S4/Bi2WO6 (CIS/BWO) heterojunction for the first time, and effectively promote photocatalytic degradation activity through piezoelectric effect. Encouragingly, 10% CIS/BWO exhibited promising diclofenac (DCF) degradation performance under co-excitation of light irradiation and ultrasonic vibration, with degradation efficiency of 99.9% within 40 min, much higher than that of photocatalysis (72.3%) and piezoelectric catalysis (60.3%) alone. Meanwhile, an in-depth study of the charge carrier separation mechanism of CIS/BWO composites under piezo-photo synergy condition is proposed. Specially, both built-in electric field induced by piezoelectric effect in BWO and Z-scheme transfer path between CIS/BWO heterojunction are beneficial to interfacial charge transferring. Moreover, the Z-scheme mechanism is further demonstrated by trapping experiments and electron spin resonance (ESR) techniques. Furthermore, the corresponding intermediates of DCF over CIS/BWO composites and possible degradation pathways were investigated by DFT calculations and liquid chromatography-mass spectrometry (LC-MS).