Synthesis and characterization of Zn and Co monocarboxy-phthalocyanines and investigation of their photocatalytic efficiency as TiO2 composites

In this study, synthesis of a group of novel A(3)B-type non-symmetrically tetrasubstituted zinc(II) and cobalt(II) phthalocyanines bearing one carboxy group (4-mercaptobenzoic acid/4-hydroxybenzoic acid) and three 4-tert-butylphenoxy substituents was achieved by a statistical condensation reaction of the corresponding two phthalonitriles. These four new phthalocyanines have been characterized by using elemental analyses, UV-vis, FT-IR, H-1 NMR and mass spectroscopic techniques. MPcs were incorporated into TiO2 semiconductors to prepare Tio(2)-MPc composites as heterogeneous catalysts. The novel composites were characterized by X-ray diffraction (XRD), infrared (FTIR) and diffuse reflectance analysis. The characterization results show that MPcs are anchored on the surface of TiO2 through CO-O-Tio(2) bonds and anatase structure of TiO2 remains unchanged after the sensitization process. The optimum loading of the dyes on TiO2 (ca. 8.4 mu mol/g Tio(2)) was almost independent of the amount of TiO2 used. The new Tio(2)MPc composites were used to test their photocatalytic activity on decomposition of 4-chlorophenol under visible light. In contrast to untreated Tio(2), all photocatalysts prepared in this study were highly effective on 4-chlorophenol under visible light and almost total photodegradation was accomplished. (C) 2017 Elsevier B.V. All rights reserved.