Facile, green encapsulation of cobalt tetrasulfophthalocyanine monomers in mesoporous silicas for the degradative hydrogen peroxide oxidation of azo dyes

► A facile and green approach to improving catalytic activity of cobalt tetrasulfophthalocyanine for removal of dyes was proposed. ► By immobilizing anionic cobalt tetrasulfophthalocyanine monomers into structure's cavities of MCM-41 with a matching pore size, a robust catalyst was prepared under certain pH conditions. ► Phthalocyanine was largely incorporated into the mesoporoes and its aggregation was prevented. ► High activity for the oxidative degradation of dyes in water with H2O2 was demonstrated. ► CoTSPc@MCM-41 could be reused effectively for the degradation of mostly common dyes.