Synthesis of new TiO2/porphyrin-based composites and photocatalytic studies on methylene blue degradation

In this study, we synthesized porphyrin dyes and structurally characterized them using H-1 and C-13 NMR and FT-IR and high-resolution mass spectrometry. By using these porphyrins, new TiO2-porphyrin catalysts (TiO2 PORPC-1, TiO2-PORPC-2, TiO2-PORPC-3 and TiO2-PORPC-4), were prepared and the structures of these catalysts were confirmed by using SEM, TEM, solid-state UV-visible spectroscopy, XPS, FT-IR spectroscopy and EDS analysis. Studies on the photodegradation of methylene blue suggested that our TiO2-porphyrin photo-catalysts were more effective for the degradation than bare TiO2-anatase, and furthermore, TiO2-Zn-porphyrins showed better photocatalytic activity than the metal-free TiO2-porphyrins because of their high charge-transfer properties. We evaluated the stability of the TiO2-porphyrins by repeatability test. Finally, we proposed a plausible mechanism for the photocatalytic activity.