PtOx deposited Fe3O4-ZnO/TiO2 nanocomposites for photocatalytic H2 production under visible light

In this work, TiO2 nanotubes, Fe3O4-ZnO, nanocomposites of Fe3O4-ZnO and TiO2 were synthesized by varying the amount (5, 10 and 15 wt%) of Fe3O4-ZnO. The obtained nanocomposites were decorated with PtOx (1.0 wt%) nanoparticles via green synthesis method using Chamomile flowers extract. The synthesized samples were thoroughly characterized by XRD, SEM, HRTEM, FT-IR, DRUV-vis, PL N2-physisorption and XPS spectroscopy measurements. The XRD, FT-IR, XPS spectroscopy and microscopy results revealed the existence of strong interaction between Fe3O4-ZnO and TiO2 nanotubes. Deposition of PtOx on the surface of TiO2, Fe3O4-ZnO and Fe3O4-ZnO/TiO2 nanocomposite samples resulted in a decrease in the bandgap to 3.26 eV, 1.90 eV and 1.80 eV respectively. Further, Fe3O4-ZnO/TiO2 nanocomposites exhibited relatively high surface area (95 m2g ? 1) and pore volume (0.174 cm3g ? 1) than Fe3O4-ZnO sample. The presence of surface PtOx species resulted in delaying the recombination of e -/h+ pairs. Different reaction conditions such as pH of solution, methanol/H2O ratio and catalyst mass were optimized to obtain high photocatalytic H2 production. The highest photocatalytic H2 pro-duction [485 & mu;mol/(gcatalysth) 1] was observed in case of Pt@Fe3O4-ZnO/TiO2-3 catalyst under visible light irradiation at 80 degrees C. In addition, the synthesized PtOx deposited nanocomposite materials could be separated easily from the reaction mixture and reused five times without considerable loss of photocatalytic activity.