Synthesis of Bi₂MoO₆ Nanosheets with Rich Oxygen Vacancies by Postsynthesis Etching Treatment for Enhanced Photocatalytic Performance

Controlled introduction of oxygen vacancies in metal oxide based photocatalysts could improve their charge carrier separation efficiencies to enhance their photocatalytic performances. In this work, oxygen vacancies were introduced in Bi2MoO6 nanosheets through a postsynthesis etching treatment by NaOH aqueous solution at room temperature for the first time, which removed the requirement of high temperature treatment, chemicals of high cost and environmental hazardness, or specific apparatus for the introduction of oxygen vacancies in previous studies. Furthermore, the crystal structure, morphology, optical properties, and energy band structures of these Bi2MoO6 nanosheets were not changed by this approach, which allowed the separation and illustration of the charge carrier separation role of oxygen vacancies for the photocatalytic performance enhancement. With the increase of oxygen vacancies, Bi2MoO6 nanosheets demonstrated improved electron–hole separation efficiency and largely enhanced photocatalytic activities as demonstrated by their effective sulfamethoxazole degradation and Escherichia coli bacteria disinfection under visible light illumination with good stability and reusability.