Photosono catalytic behaviour of phthalocyanine when supported on electrospun nanofibers: The effect of radical initiators

Abstract

In this study, two Zn phthalocyanine (ZnPc) complexes containing substituents with varying number of the methoxy groups were investigated when supported on TiO2 fibers in sono-, photo-, and photosono-catalytic degradation of Rhodamine 6 G. The ZnPc on fibers displayed higher activity than when alone. The photosonocatalytic process displayed higher degradation aptitude than sonocatalytic and photocatalytic processes. The electron paramagnetic resonance studies revealed that the photocatalytic process is instigated by singlet oxygen only. However, sonocatalytic and photosonocatalytic processes are instigated by both singlet oxygen and •OH radicals. The utilization of azo-bis-isobutyronitrile and tert-butyl hydrogen peroxide as radical initiators improved the degradation efficiency of photo-, sono- and photosono- catalytic processes. The re-used fibers from sonocatalytic process resulted in significant decrease in catalytic activity, whereas the fibers from photocatalytic process were highly reusable.