Physicochemical characterization of photocatalytic materials

Abstract

A wide range of analytical techniques has been employed to obtain the physical–chemical properties of photocatalytic semiconductors prepared as powders or thin films. The photocatalytic activity of a semiconductor material depends on both surface and structural properties. For bulk materials, the composition, crystalline structure, and electronic properties of the materials are intrinsically correlated; however, surface characteristic such as surface area, particle size distribution, and porosity can be independently modified. On the other hand, for nanomaterials, the size becomes an important feature affecting the physical properties, such as the optical band gap. Moreover, the particle size is of primary importance in heterogeneous photocatalysis, because it is directly related to the efficiency of a catalyst through the enhancement of its specific surface area. The techniques described in this chapter were divided into five major topics: elemental composition, structure and topography, surface area and porosity, and vibrational and optical properties. The most common techniques are briefly described giving some examples about their use for the analysis of a photocatalytic material.