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.