Surface Phonon Spectra of Mineral TiO2 Anatase (001) and (100)

The surface properties of TiO2 anatase are of great importance in chemical technology because this material is frequently used as a support for oxide catalysts. In the framework of an extensive study of the system V2O5/TiO2 anatase, the vibrational properties of single crystal anatase (001) and (100) have been examined by means of HREELS. Both of these surfaces are believed to provide a good lattice match with V2O5(001). Single crystal anatase samples were obtained by orienting and sawing natural minerals. The resulting samples were yellowish transparent and gave rise to a LEED image after adequate UHV cleaning. Despite the insulating character of TiO2 anatase, HREELS could be performed without charging problems, due to the natural contamination. Energy loss spectra were recorded in the range −140 to 40 meV, with an instrument resolution of about 3 meV, and displayed surface vibrational modes.