A high-performance composite CDs@Cu-HQCA/TiO2 flower photocatalyst: Synergy of complex-sensitization, TiO2-morphology control and carbon dot-surface modification

• Get CDs@Cu-HQCA/TiO 2 excellent catalysts by sensitization, shape control and modification. • TiO 2 flower and CDs modification conducive to the transmission and separation of carriers greatly. • Completely decompose and mineralize dexamethasone which is extremely difficult to be degraded. • Analyze the degradation product and pathway of dexamethasone combined DFT calculation with HRMS. A CDs@Cu-HQCA/TiO 2 flower composite photocatalyst (CDs: carbon dots, HQCA: 8-hydroxyquinoline-5-carboxylic acid) was constructed by exploiting the synergy of complex-sensitization, TiO 2 -morphology control, and carbon dot-surface modification. The photocatalytic degradation of phenol, norfloxacin, tetrabromobisphenol A and Cr (VI) by Cu-HQCA/TiO 2 particle, tube, diamond and flower-like show that the Cu-HQCA complex effectively extends the visible light absorption range of composite photocatalysts, and the flower morphology of TiO 2 not only improves the adsorption of pollutants but also enhances the photoelectric response of the composite photocatalyst. In this manner, a CDs@Cu-HQCA/TiO 2 flower catalyst that demonstrates excellent performance for the removal of dexamethasone, which does not degrade well naturally, was prepared, which delivered a rate of degradation of 99.4% and a degree of mineralization of 77.4% for dexamethasone. Possible degradation sites and dexamethasone degradation products were studied by combining computational chemistry with high-resolution mass spectrometry, and a possible mechanism for photogenerated carrier transmission and separation in the CDs@Cu-HQCA/TiO 2 flowers is proposed.