Photodegradation of rhodamine B with molecular oxygen catalyzed by a novel unsymmetrical iron porphyrazine under simulated sunlight

A novel unsymmetric biomimetic catalyst iron(II) (1,4-dithiin)(3)-4-pentyloxyphenyl-porphyrazine [abbreviated as FePzPh(1,4-dithiin)(3)] was successfully synthesized by a template method. Its photocatalytic activity was evaluated by the degradation of rhodamine B under solar-simulating Xe lamp irradiation. A high degradation ratio and TOC removal were achieved in 97.3% and 70%, respectively, at pH 9.18 in 100 min. Wavelength filter experiments demonstrated that the small portion of light with the wavelength shorter than 420 nm played a significant role in the activation of molecule oxygen to degrade RhB. The photocatalytic activity of this unsymmetric catalyst FePzPh(1,4-dithiin)(3) is higher than its symmetric matrix. Hydroxyl radicals were detected as a main reactive oxidative species, and a possible mechanism of the activation of molecular oxygen catalyzed by FePzPh(1,4-dithiin)(3) was proposed.