Visible-light-induced photocatalysis of copper phthalocyanines on cotton fibre

Abstract

There are various copper phthalocyanine (CuPc) dyes, which are the copper phthalocyanines (CuPcs) with different substituents, commonly available on the market. Several CuPc dyes were applied to cellulosic fibre for studying their photocatalytic activities by using stain decolourisation methods. Even though the molar quantity of each CuPc derivative on cotton fabric were controlled to be equivalent, there were great difference on their photocatalytic activities. Distinct extents of the CuPc molecules dissociated by the cellulosic medium, owing to different CuPc molecular structures, were observed via absorption spectroscopic analyses. Liquid chromatography-mass spectrometry (LC-MS) was employed to determine the molecular structures of the CuPcs. A novel elution profile, termed as “double-isocratic” method, was developed to separate the relatively complex mixtures of the CuPc compounds, to prevent interference against mass spectrometric detection by buffers and ion-pairing reagents. The stain decolourisation performance of CuPc dyes were also compared to one of the traditional photocatalysts, titanium dioxide (TiO2), under visible light. Stronger photocatalytic activity was exhibited by CuPc-functionalised cottons than the TiO2-coated cotton; convincing visible-light-catalytic effects were demonstrated by CuPcs on cotton under visible light. The outcomes of this study can make contributions to aggregation and photocatalytic studies of phthalocyanines in cellulosic medium; and the CuPcs defined with well-dissocated structures can be applied for functional cellulosic textiles triggered by visible light.