Sensitization of TiO2 nanoparticles with sulphonated cobalt phthalocyanine: An active photocatalyst for methylene blue degradation under visible light

In order to utilize visible light more efficiently in the photocatalytic reaction, TiO2 nanoparticles were synthesized hydrothermally in the presence of different amounts of sulphonated cobalt phthalocyanine (CoPcS). The prepared photocatalysts were characterized by X-ray diffraction, N2 physisorption, UV-Vis diffuse reflectance spectroscopy, transmission electron microscopy, thermogravimetric analysis, elemental analysis and FTIR. The characterization results show that CoPcS is anchored on the surface of TiO2 through SO2-O-TiO2 bonds. The photocatalysts were used for the degradation of methylene blue (MB) monitored by UV-Vis spectrophotometry. The catalysts revealed enhanced activity for the degradation of MB compared to that of pure TiO2, which is attributed to the cooperative function of the two components of the photocatalyst, CoPcS and semiconducting TiO2, in generating the catalytically active species. The photocatalyst containing 2.24 wt% CoPcS exhibited the highest photocatalytic activity for MB degradation.