Porous metalloporphyrinic nanospheres constructed from metal 5,10,15,20-tetraksi(4′-ethynylphenyl)porphyrin for efficient catalytic degradation of organic dyes

Abstract

Novel conjugated metalloporphyrin polymers (PP-EPMn and PX-EPMn) were synthesized by the Sonogashira coupling reaction with Mn(III)5,10,15,20-tetraksi(4′-ethynylphenyl)porphyrin ([p-ethynyl]₄PMn) as building block, and with phenylene and xenyl groups as bridges, respectively. Fine nanospheres were obtained through control of the reaction conditions. The two polymer nanospheres were characterized in detailed by BET, FE-SEM, HR-TEM, FT-IR, UV-Vis and XPS, revealing that they were highly ordered, highly developed microporous and super-conjugated metalloporphyrin polymers with large surface areas and uniform pore sizes. Their electrochemical behaviors and hydrophilicity were also investigated. With the synergistic effects of porous nanosphere structure and conjugated covalent structure, PP-EPMn and PX-EPMn showed excellent catalytic activity and reusability in the catalytic degradation of methylene blue (3,7-bis(dimethylamino)-5-phenothiazinium chloride) in aqueous solution. The good hydrophilicity of the polymer nanospheres promoted the catalytic degradation. In particular, unlike Fenton degradation systems that require acidic conditions, PP-EPMn degraded methylene blue significantly better under alkaline conditions, which implied a good prospect in treating industrial methylene blue dye wastewater.