Electron beam induced changes in transition metal oxides

Abstract

Electron beam induced changes in maximum valence transition metal oxides V2O5, MoO2 and TiO2 (anatase) were studied by means of electron energy-loss spectroscopy and electron diffraction in a transmission electron microscope. For V2O5, the observed chemical shifts of the L-edge reveal the reduction of V 5+ to V 2+ , while its structure changes from orthorhombic V2O5 to cubic VO. The orthorhombic MoO3 can be reduced to a phase with an oxidation state lower than that in MoO2. This phase has a cubic or tetragonal structure with a = c = 0.408 nm. For TiO2 (anatase), no noticeable changes in the intensity of the O K-edge can be observed. The main structure symmetry prevails during the electron irradiation.