Facile synthesis of CeO/carbonate doped BiOCO Z-scheme heterojunction for improved visible-light photocatalytic performance: Photodegradation of tetracycline and photocatalytic mechanism.

CeO nanoparticles are successfully loaded on carbonate doped BiOCO (CBOC) nanosheets by a facile hydrothermal and low-temperature calcination method. CeO/CBOC heterojunction shows significantly enhanced photocatalytic activity, when 35 mg of CeO/CBOC photocatalyst is added to tetracycline (TC) solution (20 mg/L, 100 mL), about 79.5% TC is degraded within 90 min under visible light irradiation, which is much higher than that of original CeO and CBOC. According to photoelectrochemical characterization and active radical capture experiments, the Z-scheme electron transfer mechanism is the reason for the significant enhancement of photocatalytic activity. Besides, the XPS results indicate that Ce/Ce redox pairs are formed at the contact interface between CeO and CBOC, which is conducive to the transfer of photoexcited electrons and production of superoxide radicals. Additionally, the photocatalytic mechanism and possible degradation pathway of TC is proposed through free radical trapping experiments and liquid chromatography-mass (LC-MS) analysis. This study will accumulate experience for the combination of CeO and bismuth-based nanomaterials, and provide a feasible way to design wide band-gap bismuth-based photocatalysts, thereby achieving efficient visible light degradation of environmental pollutants.