In-situ construction of Bi/defective Bi4NbO8Cl for non-noble metal based Mott-Schottky photocatalysts towards organic pollutants removal

The strategy to improve the photocatalytic performance is still a challenge for the novel Sillen-Aurivillius perovskite type Bi4NbO8Cl. Herein, heterostructured Bi/Bi4NbO8Cl was fabricated via in-situ solvothermal method, without the additional introduction of Bi-sources. Simultaneously, the amount of oxygen vacancies (OVs) were increased, as the [Bi2O2] blocks released in the solvothermal process to serve as precursors for Bi particles. Due to the large work function of Bi, a Schottky barrier formed at the Bi/Bi4NbO8Cl interface, promoting photoinduced charge separation generated in the Bi4NbO8Cl semiconductor, supplying more holes for the organic compounds decomposition, which could be widely applied in water decontamination. Furthermore, the OVs facilitate the consumption of photo-induced electrons by assisting oxygen activation to produce superoxide radicals (center dot O-2(-)), leaving more holes in the valence band of Bi4NbO8Cl, and thus result in the enhancement of Rhodamine B (RhB) degradation by 1.82 times over Bi/Bi4NbO8Cl photocatalysts. Through the synergistic effect of Bi and OVs, the Bi/Bi4NbO8Cl also exhibits enhanced photocatalytic performance towards various organic water-contaminants, such as methyl orange, acid orange 7, p-nitrophenol and tetracycline hydrochloride.