Property Characterization and Photocatalytic Activity Evaluation of BiGdO(3) Nanoparticles under Visible Light Irradiation

BiGdO(3) nanoparticles were prepared by a solid-state reaction method and applied in photocatalytic degradation of dyes in this study. BiGdO(3) was characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller, UV-Vis diffuse reflectance spectroscopy and transmission electron microscopy. The results showed that BiGdO(3) crystallized well with the fluorite-type structure, a face-centered cubic crystal system and a space group Fm3m 225. The lattice parameter of BiGdO(3) was 5.465 angstrom. The band gap of BiGdO(3) was estimated to be 2.25 eV. BiGdO(3) showed a strong optical absorption during the visible light region. Moreover, the photocatalytic activity of BiGdO(3) was evaluated by photocatalytic degradation of direct dyes in aqueous solution under visible light irradiation. BiGdO(3) demonstrated excellent photocatalytic activity in degrading Direct Orange 26 (DO-26) or Direct Red 23 (DR-23) under visible light irradiation. The photocatalytic degradation of DO-26 or DR-23 followed the first-order reaction kinetics, and the first-order rate constant was 0.0046 or 0.0023 min(−1) with BiGdO(3) as catalyst. The degradation intermediates of DO-26 were observed and the possible photocatalytic degradation pathway of DO-26 under visible light irradiation was provided. The effect of various operational parameters on the photocatalytic activity and the stability of BiGdO(3) particles were also discussed in detail. BiGdO(3)/(visible light) photocatalysis system was confirmed to be suitable for textile industry wastewater treatment.