Photocatalytic activity of TiO2/Nb2O5/PANI and TiO2/Nb2O5/RGO as new nanocomposites for degradation of organic pollutants

Highlights: • The TiO₂/Nb₂O₅/PANI and TiO₂/Nb₂O₅/RGO nanocomposites were first synthesized via hydrothermal method. • Photocatalytic degradation of organic dyes were evaluated under visible light irradiation. • TiO₂/Nb₂O₅/RGO exhibits outstanding photocatalytic efficiency under visible light. • TiO₂/Nb₂O₅/RGO nanocomposite is stable and shows excellent reusability. - Abstract: In this study, highly active titanium dioxide modified by niobium oxide (Nb₂O₅), polymer (PANI) and reduced graphene oxide (RGO) were successfully prepared. The morphology, structure, surface area and light absorption properties of the present nanocomposites for removal of methylene blue (MB) and methyl orange (MO) were investigated and compared with those of TiO₂/Nb₂O₅ and TiO₂ nanoparticles. The characterization techniques such as XRD, FT-IR, UV–vis, SEM, EDX, BET and TEM were employed in order to identify the nanocomposites. Also, photocatalytic properties of TiO₂/Nb₂O₅/PANI and TiO₂/Nb₂O₅/RGO nanocomposites under visible light irradiation were studied. In this way, the obtained results were compared to each other and also compared to TiO₂/Nb₂O₅ and TiO₂ nanoparticles. In this context, the chemical oxygen demand (COD) removal follows the photodegradation in observed performance. The results indicate that reduced TiO₂/Nb₂O₅ nanocomposite is effectively modified by graphene oxide to give TiO₂/Nb₂O₅/RGO composite. The TiO₂/Nb₂O₅/RGO exhibits significantly higher photocatalytic activity in degradation of organic dyes under visible light rather than that of TiO₂/Nb₂O₅/PANI, TiO₂/Nb₂O₅ and pure TiO₂.