Deep eutectic solvent-assisted preparation of defective TiO2 for photochemical degradation of organic pollutants

In this study, we, for the first time, employed tetrabutylammonium bromide (TBAB) as a template to synthesize black TiO2 (TBAB/G-TiO2) with a robust response to both visible and infrared light using the sol-gel method. This novel catalyst demonstrates the ability to degrade organic pollutants even without light. The characterization results of the catalyst indicate that the hydrogen bonding force of Deep Eutectic Solvent (DES) on TiO2 plays a crucial role in shaping the structure and influencing the performance of TiO2. Specifically, a stronger hydrogen bonding force results in an improved photocatalytic performance of TiO2. Influenced by the DES template, TiO2 generates numerous oxygen defects, reducing bandgap width from 3.20 eV to 1.34 eV and a specific surface area of 65.65 m2/g. Moreover, the material exhibits a remarkable response to both visible and infrared light. The evaluation of photocatalytic performance demonstrates that TBAB/G-TiO2 exhibits significantly higher activity than pure TiO2. The pseudo-first-order kinetic constant for the photocatalytic degradation of methylene blue solution is 3.39 times higher than that of pure TiO2.