Construction of novel trimeric π-interaction subphthalocyanine-sensitized titanium dioxide for highly efficient photocatalytic degradation of organic pollutants

Abstract

In this study, highly active TiO2 sensitized by a novel axial substituted subphthalocyanine H12SubPcB-OPHCH2COOH (SubPc-3) was successfully prepared via a solvothermal method. Based on the crystallographic strategy, a new packing motif of SubPc-3 consisting of ligand-convex concave-concave head-head π-interaction was discovered for the first time, which affected its catalytic performance significantly. Furthermore, the DFT and TD-DFT methods were used to study the electronic feature and excited-state properties in SubPc-3 utilizing an optimized structure. By examining the degradation of methyl orange (MO) and bromophenol blue (BB) under visible light, the photocatalytic activities of the nanocomposites were investigated. The photocatalytic degradation rate of MO and BB degradation with TiO2/SubPc-3 are 97.8% and 99.5%, which are approximately 5.26 and 1.41 times compared to pure TiO2, respectively. Besides, the reusability studies indicated that the photocatalytic activity of TiO2/SubPc-3 (25:1) could be maintained above 90.1% after five circulating photo-degradation. This work revealed the correlation between π-interaction of sensitizer and photocatalytic performance, as well as further confirmed the great potential of TiO2/SubPc-3 photocatalytic materials in environmental remediation.