FABRICATION OF SQUARAINE DYE SENSITIZED SPHERICAL ZINC OXIDE NANOCOMPOSITES AND THEIR VISIBLE-LIGHT INDUCED PHOTOCATALYTIC ACTIVITY

A 1,3-bis[(3,3-dimethylindolin-2-ylidene)methyl]squaraine (ISQ) dye sensitized ZnO nanocomposites via two different preparation methods including hydrothermal and ultrasonic sensitization processes are discussed in this paper. The as-prepared composites were characterized by the X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), Raman spectroscopy, and transmission electron microscopy (TEM). Based on the XRD patterns and TEM images, the ISQ/ZnO nanocomposites still kept the characteristic peaks and the basic morphology of ZnO and ISQ dye. The photocatalytic activity of ISQ/ZnO nanocomposites was investigated by degrading methylene blue (MB) under visible-light illumination. Compared with the MB self-degradation rate, the photocatalytic activity of the ISQ/ZnO composites was enhanced remarkably. The ISQ/ZnO nanocomposites fabricated by ultrasonic sensitization method exhibited excellent photocatalytic degradation rate, approximately 20% higher than that of the hydrothermal sensitization one.