Preparation of photocatalysts by physical methodologies

Abstract

The synthesis of photocatalytic materials is an important task for obtaining better results in terms of activity and/or selectivity in photocatalysis. This chapter reports an overview of the main methodologies using physical techniques to obtain bulky, supported powders or films and coatings to be used as heterogeneous photocatalysts. The classical chemical methodologies for the preparation of photocatalytic materials are presented in the previous chapter, so the information presented here complements the aforementioned one. Materials scientists and engineers have made significant progresses in the improvement of methods of synthesis of nanomaterial solids by developing different apparatuses supporting this aim. Various experts including physicists, chemists, material scientists, and mechanical and electrical engineers are involved in this research. New physical approaches, both for sample preparation and device fabrication, have aroused on account of the development of this nanoscience. The significant potential of the physical approach in material synthesis and their applications in photocatalysis, and other branches of catalysis and science, still needs to be explored offering numerous challenges to overcome. The understanding of these synthetic approaches would help in designing better materials. In this chapter, various methods for material preparation both bulk and supported as thin films or coatings are presented. All of them have in common the use of some apparatuses or equipments more or less sophisticated. The methodologies described include spray pyrolysis, flame synthesis, sonochemical and mechanochemical procedures, and use of microwaves as well as techniques to obtain thin films or coatings such as wet-coating synthesis methodologies, chemical and physical vapor deposition, and electrodeposition, among others, as examples of the physical approaches to prepare photocatalysts.