TiO_2-graphene nanocomposites for photocatalytic hydrogen production from splitting water

摘要

TiO_2 (P25)-graphene (P25-GR) hybrids were prepared via solvothermal reaction of gra-phene oxide and P25 using ethanol as solvent. The as-prepared P25-GR nanocomposites were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence emission spectroscopy and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. The results indicated that P25-GR nanocomposites possessed enhanced light absorption ability and charge separation efficiency. As photocatalysts, P25-GR hybrids were much better than the bare P25, when they were used in the hydrogen evolution from aqueous methanol solution under Xe-lamp illumination. A significant enhancement in the rate of hydrogen production was achieved through using P25-GR as photocatalysts, comparing to bare P25. The optimum mass ratio of GR to P25 in the hybrids was 0.5 wt%. The higher mass ratio of GR in P25-GR would decrease the photocatalytic activity of P25.