Surface Lewis acid sites and oxygen vacancies of Bi2WO6 synergistically promoted photocatalytic degradation of levofloxacin

Abstract

Ultrathin Bi2WO6 nanosheets with a high concentration of surface oxygen vacancies (BWO-OVs) are successfully constructed for the degradation of levofloxacin (LVX) under visible light irradiation and show a high degradation efficiency of LVX (≈100 %). It is revealed that the oxygen vacancies (OVs) over BWO-OVs nanosheets can not only accelerate the separation of photo-induced electrons and holes, but also activate the O2 molecules to form O2– species. The FTIR spectra and density functional theory deeply demonstrate that piperazine ring and CO groups (carboxylic acid) in LVX can be chemisorbed and activated by surface Lewis acid sites. The EPR results reveal that photo-generated holes, O2– and OH species are reactive oxygen species for the photocatalytic degradation of LVX. The possible intermediate is well investigated by LC-MS results combined with the FTIR spectra results. This work provides a new perspective for understanding photocatalytic degradation from the interaction between the active sites of a photocatalyst and antibiotics molecules.