Underneath mechanisms into the super effective degradation of PFOA by BiOF nanosheets with tunable oxygen vacancies on exposed (101) facets

Construction of surface defects or/and exposed reactive facets is a promising strategy to improve the performance of photocatalysts. In this study, BiOF photocatalysts with tunable oxygen vacancies on the exposed (101) facets were successfully prepared by adjusting the concentration of ethylene glycol (EG). The prepared product with 50 % EG in the solution displayed remarkable photocatalytic activity for the recalcitrant pollutant perfluorooctanoic acid (PFOA), which could be completely decomposed within 6 h. The appropriate concentration of oxygen vacancy and the exposed (101) facets synergistically promoted the electron transfer from the defective surface to O2. Moreover, the oxygen vacancy introduced an intermediate band, which narrowed the bandgap and lowered the energy required for electron transition. DFT calculations and LC-MS-MS results revealed the principal-attack-sites of various active substances and figure out the entire PFOA degradation pathways. These profound findings are instrumental for a comprehensive understanding of the degradation process of PFOA in photocatalytic systems.