Enhancing photocatalytic performance of F-doped TiO2 through the integration of small amounts of a quinoline-based covalent triazine framework

Abstract

We present the design and synthesis of a new quinoline-based covalent triazine framework (Quin-CTF) that combines two photoactive fragments within its structure (triazine and quinoline moieties). By hybridizing this CTF material with fluorine-doped titanium dioxide (F-TiO₂), we prepared and characterized photocatalysts with enhanced performance that leverage the synergy between the two components for pollutant photodegradation in water. This F-TiO₂@CTF hybrid system was evaluated for the photocatalytic degradation of methylene blue dye and a pharmaceutical compound such as ciprofloxacin as model water pollutants. The hybrid materials containing small amounts of CTF (0.5, 1, and 2 wt%) achieved remarkable photodegradation efficiencies, significantly outperforming their individual counterparts. The reactive oxidant species (ROS) involved in such processes catalyzed by F-TiO₂ are different from those involved when pristine Quin-CTF or their hybrid materials are used. Furthermore, the hybrid materials demonstrated reusability, preserving high photocatalytic activity over multiple cycles. This work, therefore, highlights a promising strategy for designing cost-effective and eco-friendly photocatalytic systems via the incorporation of a small amount of CTF-based systems in a cheap material such as titanium dioxide, offering a sustainable and effective solution for mitigating water pollution.