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 chal-lenges encountered with conventional technologies for environmental remediation. In this research, Z-scheme heterostructure composed of core-shell Au@TiO2 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 (Au@TiO2/Bi2WO6) were further investigated in detail. Benefitted from the synergy of the heterojunction construction and metallic surface plasmon resonance effect, the Au@TiO2/Bi2WO6 with an optimal mass ratio of Au@TiO2 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 enhance-ment compared with single Bi2WO6, respectively. In addition, the cyclic stability and photocatalytic mechanism of Au@TiO2/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.(c) 2022 Elsevier B.V. All rights reserved.