Z-scheme Au@TiO2/Bi2WO6 heterojunction as efficient visible-light photocatalyst for degradation of antibiotics

Semiconductor photocatalysis can be regarded as one of effective strategies to overcome the great challenges encountered with conventional technologies for environmental remediation. In this research, Z-scheme heterostructure composed of core–shell [email protected]O2 nanoparticles and flower-like Bi2WO6 nanosheets has been successfully prepared through the reverse micelle sol–gel method followed by a hydrothermal process. The structural characteristics, chemical compositions and photoelectrochemical properties of this ternary composite photocatalyst ([email protected]2/Bi2WO6) were further investigated in detail. Benefitted from the synergy of the heterojunction construction and metallic surface plasmon resonance effect, the [email protected]2/Bi2WO6 with an optimal mass ratio of [email protected]2 to Bi2WO6 exhibited the significantly enhanced photocatalytic activity for degradation of antibiotics under visible-light irradiation, in which the degradation efficiency of sulfamethoxazole (SMX) and tetracycline hydrochloride (TC) could be up to 96.9% and 95.0% within 75 min, respectively. The reaction rate constant for SMX and TC degradation was calculated to be around 0.0425 min−1 and 0.0314 min−1, which has 7.2 times and 1.9 times enhancement compared with single Bi2WO6, respectively. In addition, the cyclic stability and photocatalytic mechanism of [email protected]2/Bi2WO6 were further verified. Our primary results provide a feasible strategy to develop core–shell heterostructured photocatalysts with superior performance for the efficient removal of low-concentration antibiotics in water.