Highly efficient degradation of sulindac under visible light irradiation by a novel titanium based photocatalyst

Titanium dioxide (TiO₂) is a kind of generally used photocatalyst with the assistance of UV light. To utilize the visible light and save the energy, herein, a titanium (Ti)-based nanocomposite, i.e. PPDs/C-hTiO₂, was designed and prepared based on carbon (C)-doping and photosensitive polymer dots (PPDs) nano-hybridization. This design synergistically narrowed the band gap energy (E_g) and strengthened absorption of the visible light. As a result, PPDs/C-hTiO₂ exerted remarkably high catalytic ability under visible light, surpassing that of commercial TiO₂ (i.e. P25) under UV light. PPDs/C-hTiO₂ succeeded in assisting the degradation of sulindac with a degradation efficiency of 96.7%±1.25% within 10 min under visible light. The degradation process was driven by the generation of hydroxyl radical, superoxide radical and holes, and the total biotoxicity of degradation products was decreased compared to the parent compound. This study creatively combined the C-doping and PPDs nano-hybridization to construct a visible light Ti-based photocatalyst, proposing a potential technique for addressing current aquatic environmental issues.