Bulk and surface characterization techniques of TiO₂ and TiO₂-doped oxides

The correlations between surface and bulk properties of TiO2 and TiO2-doped oxides with their photocatalytic and catalytic performances are fundamental to understanding the basic mechanisms of action and to design new materials with enhanced properties. TiO2-based oxides have been most widely investigated in the past decades as photocatalysts and many comprehensive review articles have reported the advances made in the field of TiO2-based photocatalysis, while poor attention has been paid to the use of TiO2 in heterogeneous catalysis, as a catalyst itself, or as support for noble metals. Moreover, as far as we know, no previous review articles or book chapters have analyzed the relationship between characterizations of both surface/bulk properties of TiO2 and TiO2-doped oxides, with their photocatalytic and catalytic activity. This chapter aims to discuss some structural and surface properties of TiO2 and TiO2-doped oxides, investigated by using the following techniques: X-ray diffraction, transmission electron microscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, and acidity measurements. To this purpose, some selected recent articles are presented and the relationship structure-activity and photocatalytic activity is attempted.