Fe/TiO2: A Visible Light Active Photocatalyst for the Continuous Production of Hydrogen from Water Splitting Under Solar Irradiation

Abstract

A series of Fe/TiO2 catalysts with varying amounts of Fe (0.2–2.0 wt%) were prepared by doping of Fe on the surface of nano TiO2. The XPS results revealed that Fe exists in Fe3+ state in a strong interaction with TiO2. The strong absorption band for Fe/TiO2 in the range of 440–575 nm infers the modification of TiO2 surface with Fe dopant. N2 adsorption, TEM and SEM studies proved that the catalysts are mesoporous with high surface area and nanosized particle in size (≈5 nm). Photocatalytic activity of the catalysts was evaluated for the generation of H2 from water splitting under solar irradiation. Optimisation of Fe3+ ion doped over the surface of TiO2 was studied, it is observed that 0.5 wt% Fe/TiO2 catalyst exhibited enhanced hydrogen yield of 270 μmol-H2/h activity, while un doped TiO2 shows 2.8 μmol-H2/h.The improved photocatalytic activity of Fe/TiO2 can be attributed to synergistic effects such as band gap in the visible region and minimum electron hole recombination over the surface by the formation of electron trapping centres. Fe/TiO2, a nano and mesporous visible light active photocatalyst shows highly enhanced hydrogen production under solar irradiation. Surface doping of metal ions seems to be more suitable than the lattice doping for the enhanced photocatalytic activity.