Local structure of Mo-doped TiO2 photocatalysts investigated by X-ray absorption fine structure

Abstract

The local structures of Mo-doped TiO2 photocatalysts are investigated by X-ray absorption fine structure spectroscopy (XAFS) combined with X-ray diffraction (XRD). The XRD patterns show that all the Mo-doped TiO2 samples maintain the high qualitative anatase TiO2 structure without any visible diffraction peak related to Mo. The detailed XANES and EXAFS analysis reveal that all of the Mo atoms substitute Ti atoms in the anatase lattice as Mo6+ with doping concentration as high as 6 atom %. Combined with theoretical calculation, we suggested that the high electron density of Mo-O causes the strong shrinkage of ~0.1 Å for Mo-O bond length in Mo-doped TiO2.