Photocatalytic activity of nanohybrid Co-TCPP@TiO2/WO3 in aerobic oxidation of alcohols under visible light

Abstract

Here the photocatalytic performance activity of a novel Co-TCPP@TiO₂/WO₃ nanohybrid toward selective alcohol oxidation is reported. The Co-TCPP@TiO₂/WO₃ nanohybrid was prepared in three major steps. After the synthesis of nano-disk WO₃ by a new green chemical method using natural pomegranate juice, a TiO₂/WO₃ nanocomposite was obtained via a sonochemical assisted hydrothermal method, followed by anchoring of cobalt(II)-meso-tetra(4-carboxyphenyl)porphyrin (Co-TCPP) on TiO₂/WO₃. All intermediate nanomaterials and the final nanohybrid compound were characterized by FE-SEM, EDAX, XRD, DRS and FT-IR spectroscopy. The photocatalytic behavior of the TiO₂/WO₃ nanocomposite and Co-TCPP@TiO₂/WO₃ nanohybrid were investigated in oxidation of primary alcohols under visible light irradiation in the presence of air as the oxygen source. The progress of the catalytic reactions was monitored using a TLC technique. Remarkably, the photocatalytic performance of the TiO₂/WO₃ nanocomposite was enhanced from 70 to 95% by anchoring the TCPP on the composite. This nanohybrid catalyst was reused and recovered ten times without losing photocatalytic activity. In fact, nanohybrid Co-TCPP@TiO₂/WO₃ shows an extremely higher efficiency and shorter reaction time (1 h) than the TiO₂/WO₃ nanocomposite. So, this nanohybrid compound has the potential to be used as a high performance heterogeneous photocatalyst under visible light irradiation for oxidation reactions, with advantages of high activity, high selectivity, reusability and easy separation.