Versatility of CoPcS in CoPcS/TiO(2) for MB degradation: photosensitization, charge separation and oxygen activation

In this report, a composite photocatalyst consisting of cobalt phthalocyanine sulfate (CoPcS) and TiO(2) was prepared by a facile synthesis. Careful characterizations and measurements indicate a covalent grafting of CoPcS onto TiO(2) through Ti–O–S linkages, acquiring an intimate heterojunction between TiO(2) and CoPcS. The obtained composite was evaluated for its photocatalytic activity toward the degradation of methyl blue (MB) under visible light irradiation. The evaluation showed a significantly enhanced degradation rate of MB by CoPcS/TiO(2). The improved photocatalytic performance of CoPcS/TiO(2) was attributed to the photosensitization of TiO(2) by CoPcS, charge separation by electron transfer at the interface of the heterojunction formed between CoPcS and TiO(2), and oxygen activation via CoPcS. A synergetic mechanism in improving the photocatalytic performance of TiO(2) by CoPcS was investigated.