Preparation of multilayer strontium-doped TiO2/CDs with enhanced photocatalytic efficiency for enrofloxacin removal

Multilayer strontium-doped TiO 2 /carbon dots (CDs) materials (TC) were produced via sol-gel-layered carbonization method. A thorough analysis of the fabricated composites via XRD, SEM, and XPS revealed that strontium ions, TiO 2 and CDs, were combined with each other to form layered structures. According to the UV-Vis diffuse reflectance spectrograms and ( αhv ) 1/2 vs. hv plots, the electron-donor property of strontium ions caused a more positive TC conduction band position than that in the pure TiO 2 , thereby increasing the visible-light absorption range of TC. Based on the photocatalytic degradation data, the degradation rate of enrofloxacin was 84.7% at the dosage of 0.05 g·L −1 and the concentration of 10 mg·L −1 . The capture experiments and ESR results showed that ·O 2 − and e − played a major role in the degradation process of TC. The possible degradation mechanism of enrofloxacin was explained in terms of decarboxylation and defluorination, as was detected via ultra-performance liquid chromatography–mass spectrometry (UPLC-MS) analysis. Graphical Abstract