Solvothermal synthesis of copper-doped BiOBr microflowers with enhanced adsorption and visible-light driven photocatalytic degradation of norfloxacin

[Display omitted] •Copper doped BiOBr (Cu-doped BiOBr) was synthesized using a one-step hydrothermal method.•Cu-doped BiOBr showed much higher visible-light-driven photocatalytic activity for norfloxacin degradation.•The doping of copper in BiOBr enhance the norfloxacin adsorption on photocatalyst surface.•The photocatalytic activity of Cu-doped BiOBr in the fifth cycle easily maintained 95% of the activity in the first cycle. Photocatalysts based on copper-doped bismuth oxybromide (Cu-doped BiOBr) were synthesised using a solvothermal method and assessed for their ability to degrade norfloxacin under visible light. The Cu atoms were successfully doped into the crystal lattice of BiOBr, yielding Cu-doped BiOBr microflowers with a morphology and crystal structure identical to that of pristine BiOBr. The as-prepared Cu-doped BiOBr showed activity superior to BiOBr in the photocatalytic degradation of norfloxacin under visible-light irradiation, which was attributed to its improved light-harvesting properties, enhanced charge separation and interfacial charge transfer. Furthermore, we found for the first time that the introduction of Cu into BiOBr enhanced the adsorption capacity between the photocatalyst and norfloxacin, which we considered to be the main contribution to its improved performance. Cu-doped BiOBr containing the optimal proportion of Cu and Bi (Cu:Bi = 0.03) had a photocatalytic degradation constant of 0.64 ×10−2 min−1, which is 2.28 times higher than that of undoped BiOBr. The primary oxidation pathway was determined to involve the transfer of photogenerated holes to norfloxacin. Finally, we demonstrated that the Cu-doped BiOBr photocatalyst retained 95% of its initial activity even after five successive catalytic cycles, confirming its recyclability.