Quaternized zinc(II) phthalocyanine-sensitized TiO2: surfactant-modified sol-gel synthesis, characterization and photocatalytic applications

TiO2 nanoparticles and zinc phthalocyanine-sensitized TiO2 (ZnPc/TiO2) nanocomposite were synthesized in the presence and absence of Triton X100 (a nonionic surfactant) by a modified sol-gelmethod to improve the photocatalytic activity of TiO2 under near visible light (365nm). A novel quaternized ZnPc molecule was used as sensitizer. Prepared nanoparticles and nanocomposite were characterized by scanning electron microscopy, energy dispersive analysis, X-ray diffractometry, transmission electron microscopy (TEM), Brunauer-Emmett-Teller, thermogravimetry analysis, and UV-vis-NIR. The results demonstrated that the ZnPc was successfully loaded on the TiO2 nanoparticles and the nanocomposite possesses the anatase crystalline phase with the specific surface area of 110.04m(2)g(-1). The TEM micrograph showed that the average grain crystal size is 5-15nm. ZnPc in the TiO2 structure shifted the absorption edge to visible region. The photocatalytic activities of prepared photocatalysts (ZnPc/TiO2, ZnPc/TiO2-TX100, TiO2, and TiO2-TX100) were evaluated for degradative removal of methyl orange and reductive removal of Cr(VI) ions as test pollutants. Results of photocatalytic removal revealed that the ZnPc/TiO2-TX100 has shown much more photocatalytic efficiencies than the ZnPc/TiO2 prepared without TX100 and neat TiO2 prepared with or without TX100. Therefore, this sol-gel method modified with TX100 is useful in the preparation of nanostructure ZnPc/TiO2 with high photocatalytic activity and higher surface area.