Preparation, surface state and band structure studies of SrTi(1 − x)Fe(x)O(3 − δ) (x = 0–1) perovskite-type nano structure by X-ray and ultraviolet photoelectron spectroscopy

Abstract

In this report, SrTi(1−x)Fe(x)O(3−δ) photocatalyst powder was synthesized by a high temperature solid state reaction method. The morphology, crystalline structures of obtained samples, was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), respectively. The electronic properties and local structure of the perovskite STFx (0≤x≤1) systems have been probed by extended X-ray absorption fine structure (EXAFS) spectroscopy. The effects of iron doping level x (x=0–1) on the crystal structure and chemical state of the STFx have been investigated by X-ray photoelectron spectroscopy and the valence band edges for electronic band gaps were obtained for STFx by ultraviolet photoelectron spectroscopy (UPS). A single cubic perovskite phase of STFx oxide was successfully obtained at 1200°C for 24h by the solid state reaction method. The XPS results showed that the iron present in the STFx perovskite structure is composed of a mixture of Fe3+ and Fe4+ (SrTi(1−x)[Fe3+, Fe4+](x)O(3−δ)). When the content x of iron doping was increased, the amount of Fe3+ and Fe4+ increased significantly and the oxygen lattice decreased on the surface of STFx oxide. The UPS data has confirmed that with more substitution of iron, the position of the valence band decreased.