Preparation of direct Z-scheme heterojunction la-doped Bi2WO6/CdS with enhanced visible light absorption and its photocatalytic degradation of antibiotics

In this paper, a novel direct Z-scheme heterojunction La-Bi 2 WO 6 /CdS composed of 3-dimensional flower-like Bi 2 WO 6 and hexagonally stacked succulent CdS was successfully designed and synthesized. The morphology, optical properties, element valence and crystal structure of the catalysts were systematically characterized. When the dosage of LBC-40 was 1.0 g/L, the degradation rate of oxytetracycline (OTC, 20 mg/L, pH = 6) was 85.28 %, under low visible light illumination (65 W energy saving lamp) for 120 min and the reaction kinetic constant (0.01336 min −1 ) was 2.50 and 1.56 times that of pure Bi 2 WO 6 and La-Bi 2 WO 6 , respectively. Moreover, La-Bi 2 WO 6 /CdS showed good photocatalytic activity for other single antibiotics, mixed antibiotics and antibiotics from different water sources. The photocatalytic activity only decreased by 7.69 % after 3 cycles. Furthermore, the possible photocatalytic degradation pathway and photocatalytic mechanism of OTC were proposed. The excellent photocatalytic performance of La-Bi 2 WO 6 /CdS is for that the doping of La 3+ and the construction of direct Z-scheme heterojunction enhances the visible light absorption capacity and separation efficiency of photogenerated electron-hole pairs. This paper reports a new method, which can provide a reference for the design and development of visible light responsive photocatalysts with excellent photocatalytic properties.