Preparation of AgPO/CoWO S-scheme heterojunction and study on sonocatalytic degradation of tetracycline.

In this study, 0.6AgPO/CoWO composites were synthesized by hydrothermal method. The prepared materials were systematically characterized by techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), N adsorption/desorption, and UV-vis diffuse reflectance spectrum (DRS). Furthermore, the sonocatalytic degradation performance of 0.6AgPO/CoWO composites towards tetracycline (TC) was investigated under ultrasonic radiation. The results showed that, combined with potassium persulfate (KSO), the 0.6AgPO/CoWO composites achieved a high sonocatalytic degradation efficiency of 97.89 % within 10 min, which was much better than bare AgPO or CoWO. By measuring the electrochemical properties, it was proposed that the degradation mechanism of 0.6AgPO/CoWO is the formation of S-scheme heterojunction, which increases the separation efficiency of electron-hole pairs (e-h) and generates more electrons and holes, thereby enhancing the degradation activity. The scavenger experiments confirmed that hole (h) was the primary active substance in degrading TC, and free radicals (OH) and superoxide anion radical (O) were auxiliary active substances. The results indicated that 0.6AgPO/CoWO nanocomposites could be used as an efficient and reliable sonocatalyst for wastewater treatment.