Gd2O3 nanoparticles modified g-C3N4 with enhanced photocatalysis activity for degradation of organic pollutants

Gd2O3 nanoparticles modified g-C3N4 photocatalytic composites were synthesized by a simple one-step hydrothermal method. The structure, morphology, optical properties of the prepared photocatalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and X-ray photoelectron spectroscopy (XPS). The result demonstrates that gadolinium is mainly dispersed on the surface of g-C3N4 in the form of Gd2O3, and does not destroy the lattice structure of g-C3N4. Besides, the gadolinium can cause the red shift of the absorption edge of light, narrow the band gap, and increase the separation efficiency of the photogenerated electron and hole of g-C3N4. Especially, the specific surface area of g-C3N4 can be significantly increased. Furthermore, g-C3N4/Gd-0.05 displays the highest photodegradation performance when it is used for degradation of methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB). The photodegradation rate of g-C3N4/Gd-0.05 composites is 72.4% for MO, 95.5% for RhB, 100% for MB after 120 min under visible light (λ > 420 nm) irradiation. Narrow band gap promotes the separation of photogenerated electron and hole, which enhances the photocatalytic activity of g-C3N4. It is noted that g-C3N4/Gd-0.05 exhibits excellent photocatalytic stability by the photocurrent and the cyclic photodegradation of MO.