Design of CdZnS/BiOCl heterostructure as a highly-efficient piezo-photocatalyst for removal of antibiotic

Facilitating the surface and bulk photocarrier separation in semiconductors is crucially important for enhancing their photocatalytic activities. In this study, we have immobilized CdxZn1_ xS (x = 0.7) nanoparticles on the surface of (001)-facet-exposed BiOCl (BOC) nanosheets to form heterostructured CZS/BOC piezo-photocatalysts. Experiments and theories were performed to unveil the piezo-photocatalytic performances of the CZS/BOC heterostructures and involved mechanisms. It is corroborated that the CZS/BOC heterostructures exhibit efficient transfer/separation of photocarriers, and hence possess excellent photocatalysis for eliminating tetracycline hydrochloride (TC). When irradiated by simulated sunlight, the 20 %CZS/BOC heterostructure manifests a photocatalytic activity with eta(40 min)/kapp = 95 %/0.06825 min_ 1, which is enhanced by 6.9 (or 1.9) times over that of bare BOC (or Cd0.7Zn0.3S). While exerting ultrasonic vibration during the simulated-sunlight illumination, i.e., for the piezo-photocatalysis, a further improvement in the TC degradation rate is observed. The synergistic factor is calculated to be 1.5, quantifying the enhancement degree achieved by piezo-photocatalysis collaboration. The enhanced piezo-photocatalysis can be interpreted by the accelerated separation of the bulk photoelectrons and photoholes in the photocatalysts resulted from ultrasonic-induced polarization field, thus elevating their utilization for redox reactions. This work could advance the application of piezo-photocatalysts in environmental remediation.