Solvothermal fabrication of Bi2MoO6 nanocrystals with tunable oxygen vacancies and excellent photocatalytic oxidation performance in quinoline production and antibiotics degradation

Novel Bi2MoO6 nanocrystals with tunable oxygen vacancies have been developed via a facile low-cost approach with the assistance of a glyoxal reductant under solvothermal conditions. With the introduction of oxygen vacancies, the optical absorption of Bi2MoO6 is extended and its bandgap narrowed. Oxygen vacancies not only lead to the appearance of a defect band level in the forbidden band but can also result in a minor up-shift of the valence band maximum, promoting the mobility of photogenerated holes. Moreover, oxygen vacancies can act as electron acceptors, temporarily capturing electrons excited by light and reducing the recombination of electrons and holes. At the same time, oxygen vacancies help to capture oxygen, which reacts with the captured photogenerated electrons to generate more superoxide radicals (•O2−) to participate in the reaction, thereby significantly promoting the redox performance of the photocatalyst. From Bi2MoO6 containing these oxygen vacancies (OVBMO), excellent photocatalytic performance has been obtained for the oxidation of 1,2,3,4-tetrahydroquinoline to produce quinoline and cause antibiotic degradation. The reaction mechanism of the oxidation of 1,2,3,4-tetrahydroquinoline to quinoline over the OVBMO materials is elucidated in terms of heterogeneous Catal. via a radical pathway.