Copper(II) phthalocyanine tetrasulfonate sensitized nanocrystalline titania photocatalyst: Synthesis in situ and photocatalysis under visible light

Copper(II) phthalocyanine tetrasulfonate (CuPcTs) sensitized nanocrystalline anatase TiO2 photocatalyst was synthesized in situ at low temperature in a short time employing ultrasonic irradiation. The XRD patterns demonstrated that TiO2 was anatase structured, and the TEM images displayed that the average particle sizes of the as-prepared powders were nanometric (50–60 nm). The DRS data indicated that the CuPcTs-sensitized TiO2 had obvious absorption band in the visible light region, and the intensity of the monomeric CuPcTs absorption peak increased relative to the dimer due to the desorption or deaggregation of the dimeric after heat treatment below 200 °C. The results of photodecomposition of methyl orange revealed that CuPcTs–TiO2 had much more photocatalytic activity than CuPcTs or pure TiO2, and the monomeric CuPcTs-sensitized TiO2 was more photocatalytic than the dimeric CuPcTs-sensitized TiO2 under the visible light (λ > 450 nm). The stability investigation indicated that the oxidized state of CuPcTs could be reduced by methyl orange or other intermediate substances, which promoted the regeneration of CuPcTs dye.