Enhanced visible-light photocatalytic activity of Ag2O/g-C3N4 p-n heterojunctions synthesized via a photochemical route for degradation of tetracycline hydrochloride

Ag2O/g-C3N4 p-n heterojunctions were successfully fabricated by a facile photochemical method and applied as a photocatalyst in the degradation of antibiotic tetracycline hydrochloride (TC-HCl) under visible light irradiation. The samples were well characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). The results demonstrated that Ag2O nanoparticles with sizes of 5-15 nm were distributed on the surface of g-C3N4 to form the Ag2O/g-C3N4 p-n heterojunctions. The heterojunctions were conducive to the high dispersibility of small Ag2O nanoparticles and the efficient separation of photogenerated electron-hole pairs, resulting in the enhancement of photocatalytic activity by using Ag2O/g-C3N4 heterojunctions as the photocatalyst compared to pure Ag2O and g-C3N4 in TC-HCl degradation. In particular, the degradation rate of TC-HCl was 1.21 and 3.52 times higher than that of pure Ag2O and g-C3N4, respectively. Furthermore, the stability of the Ag2O/g-C3N4 photocatalyst toward the degradation process under visible light irradiation was investigated.