Direct microwave–hydrothermal synthesis of Fe-doped titania with extended visible-light response and enhanced H2-production performance

Abstract

Fe-doped TiO2 photocatalysts were synthesized rapidly and directly by the microwave–hydrothermal method and evaluated for hydrogen production by water splitting under UV–vis irradiation. The photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption–desorption isotherms, inductively coupled plasma atomic emission spectroscopy, UV–vis spectroscopy, X-ray photoelectron spectra and photoelectrochemical experiments. The results showed that Fe-doped TiO2 photocatalysts synthesized by the microwave–hydrothermal method exhibited a smaller crystallite size and higher specific surface area than TiO2 photocatalysts. The microwave–hydrothermal method was a feasible way to increase the Fe doping concentration with enhanced electron–hole separation and electron transfer efficiency. It was also observed by first-principles density functional theory calculations that Fe can induce the formation of impurity levels near the valence band, leading to the reduction of the band gap and the improvement of photocatalytic activity. The highest photoactivity was achieved for TiO2 doped with 0.5% Fe with a hydrogen production rate of 10.95μmolh−1.