Design of Composites Porphyrin-based Materials Used as Biomimetic Catalysts for the Photodegradation of Pollutants

Biomimetic catalysts such as metalloporphyrins have been used to perform oxidation reactions. The increasing demand for such catalysts gave input to various researches for new efficient systems able to mime natural enzymatic models such as cytochrome P-450 monoxygenase and other biomimetic processes based on metalloporphyrin catalysts. However, natural porphyrins, depending on their molecular structure and process parameters, are unstable under catalytic oxidation conditions due to their self-destruction. An alternative approach consists in the preparation of robust catalysts miming the catalytic center of natural enzymes which can be obtained by immobilization of conveniently functionalized metalloporphyrins onto appropriate supports. In the light of these considerations, new composite materials inspired to mime the functions of material systems in nature have been designed in order to perform photocatalytic processes for the degradation of organic pollutants. In the last years a new category of TiO2 based composites prepared by impregnation of bare polycrystalline TiO2 powders with different porphyrins and phthalocyanines (acting as sensitizers) permitted the improvement of the photocatalytic processes for degradation of pollutants both under UV or visible light irradiation. In this context will be reported the synthesis of different metal free porphyrins (H2Pps) and their corresponding metal complexes (MPps) as well as the preparation of MPps/TiO2-based composites used as efficient catalysts (compared with bare TiO2) for the photodegradation of pollutants in water as well as in vapor phase reactions.