New hybrid materials based on halogenated metalloporphyrins for enhanced visible light photocatalysis

• Published in: RSC advances 2015-01, Vol.5 (113), p.93252-93261
• Main Authors: D browski, Janusz M, Pucelik, Barbara, Pereira, Mariette M, Arnaut, Luis G, Macyk, Wojciech, Stochel, Gra yna
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c5ra19742b

Photophysical and photochemical studies on 5,10,15,20-tetrakis(2,6-difluoro-5- N -methylsulfamylophenyl)porphyrin (F 2 PMet) and its cobalt( iii ) and zinc( ii ) complexes, including spectroscopic characteristics, photostability and photocatalytic activity, were carried out. The hybrid materials resulting from adsorption of these tetrapyrroles at the surface of titanium dioxide were prepared and examined in terms of their morphological, optical and functional properties applying absorption spectroscopy, scanning electron microscopy (SEM), photoelectrochemistry and photocatalytic tests. Our studies revealed that MF 2 PMet@TiO 2 photocatalysts can be considered as the hybrid organic/inorganic photoactive materials enabling photodegradation of a synthetic opioid such as tramadol hydrochloride (TRML) and a model pollutant, 4-chlorophenol, in aqueous solution under visible light irradiation ( λ > 400 nm). To elucidate mechanisms of photochemical processes, the photocatalytic activity of investigated metalloporphyrins was compared in homo- and heterogeneous systems. The results indicate that impregnation of TiO 2 (P25) with functionalized porphyrins can improve its photoactivity. ZnF 2 PMet@TiO 2 exhibited a superior photocatalytic performance towards TRML degradation. The role of singlet oxygen and hydroxyl radicals in photodegradation processes has been elucidated both for MF 2 PMet and MF 2 PMet@TiO 2 systems. The impregnation of TiO 2 with functionalized halogenated (metallo)porphyrins leads to novel materials with a superior photocatalytic activity.