Enhanced photocatalytic hydrogen evolution by novel Nb-doped SnO ₂ /V ₂ O ₅ heteronanostructures under visible light with simultaneous basic red 46 dye degradation

To develop high-efficiency nanostructured photocatalysts, novel Nb-doped SnO2/V2O5 heterostructured nanocomposites were fabricated via combining hydrothermal and liquid-phase deposition-based processes. The formed heteronanostructures consisted of SnO2 nanotubes with a diameter of 100 nm doped with different Nb contents and V2O5 nanoparticles on their surfaces. The morphology, composition, structural and optical properties of the products were evaluated in detail by FESEM, EDS, XPS, XRD, Raman, PL, and UV-vis spectroscopy analysis. The Nb-doped SnO2/V2O5 nanocomposite exhibited higher photocatalytic activity concerning the degradation of Basic Red 46 (BR46) and H2 production under visible-light irradiation (λ ≥ 420 nm) as compared to P25, pristine SnO2 nanotubes, and SnO2/V2O5. The optimum content of 2.0 mol% was found for Nb-doping with a BR46 degradation rate of 0.0323 min−1 and an H2 production rate of 1346 μmol.g−1.h−1, which were about 3.8 and 3.4 times higher than those of P25 (0.0086 min−1 and 400 μmol.g−1.h−1), respectively. This enhancement is explained by the increased light absorption, efficient separation and transfer charge carriers as confirmed by photoluminescence and transient photocurrent response measurements. Further discussion has been presented on the mechanism and synergistic role of Nb-doping, as well as the coupling of SnO2 nanotubes with V2O5 nanoparticles for enhanced photoactivity.