Synthesis of isoamoxyphthalocyanine-attapulgite composites and its efficient photocatalytic degradation of malachite green under visible-light irradiation

Immobilizing of attapulgite into phthalocyanine not only enhanced the catalytic efficiency of metal phthalocyanine compound materials but also prevented the aggregation of phthalocyanines. Therefore, a novel isoamoxyphthalocyanine-attapulgite (ZnPc(3-iso-PeO)4-ATP) composites were fabricated by the ultrasonic impregnation menthod. The as-prepared ZnPc(3-iso-PeO)4-ATP composites were characterized by powder X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy (SEM), transmission electron microscopy, thermogravimetric analysis and UV–Vis diffuse reflectance spectroscopy spectra. The photocatalytic activities of as-obtained photocatalysts were measured by the degradation of malachite green (MG) under visible-light irradiation. The optimal conditions for the degradation of MG were determined with changing kind of catalysts and the ratio of phthalocyanine to attapulgite. In the ZnPc(3-iso-PeO)4-ATP system, it was demonstrated that preventing the aggregation of phthalocyanines was helpful to enhance the photocatalytic property. It was found that the degradation efficiency of MG reached 70% after 50 min when the ratio of ZnPc(3-iso-PeO)4 to ATP was up to 2:1. Furthermore, the possible visible-light photocatalytic mechanism of ZnPc(3-iso-PeO)4-ATP composites for the photodegradation of MG was also discussed. The excellent activity is mainly attributed to its more effective separation of electron–hole pairs.