The chapter deals with the efforts done by the scientific and industrial community in order to define standardization criteria of heterogeneous photocatalytic systems. Despite the photocatalysis industry has grown very much in the last 10 years, the lacking of standard evaluation methods for photocatalytic products hinders that the consumers understand well the performance of photocatalytic products, or that they may correctly compare the products from several producers. The establishment of standard evaluation methods for photocatalytic products is therefore a challenge for increasing their diffusion in the industrial and private field. The Chapter describes the efficiency parameters proposed for evaluating the photocatalytic systems as quantum yield, the photochemical thermodynamic efficiency factor, and two figures-of-merit: the “Electric Energy per Mass” and the “Electric Energy per Order”.
The comparison of photocatalytic systems is also carried out experimentally. The evaluation of photocatalytic films is based on the decolourisation of different dyes, such as methylene blue, or on the photo-oxidation of organic solid films such as stearic acid deposited on the surfaces. In the general field of self cleaning surfaces a scale application of TiO