The piezoelectric effect triggered by mechanical energy
could establish
an internal electric field to effectively modulate the separation
behavior of carriers. Herein, a novel CdIn2S4/Bi2WO6 (CIS/BWO) piezo-photocatalyst for removing
diclofenac (DCF) from water was constructed for the first time. Encouragingly,
the photocatalytic degradation activity of CIS/BWO was effectively
promoted through the piezoelectric effect. Specifically, 10% CIS/BWO
exhibited promising DCF degradation performance under co-excitation
of light irradiation and ultrasonic vibration, with a degradation
efficiency of 99.9% within 40 min, much higher than that of pure photocatalysts
(72.3%) and piezocatalysts (60.3%). Meanwhile, an in-depth study of
the charge carrier separation mechanism of the CIS/BWO composite under
the piezo-photo synergy condition was proposed. Both the built-in
electric field induced by the piezoelectric effect in BWO and the
Z-scheme transfer path of the CIS/BWO heterojunction are beneficial
to interfacial charge transfer. Moreover, the Z-scheme mechanism was
further demonstrated by trapping experiments and the electron spin
resonance (ESR) technique. Finally, the corresponding intermediates
of DCF over CIS/BWO composites and possible degradation pathways were
also investigated by DFT calculations and liquid chromatography–mass
spectrometry.