Effect of surface and internal Bi0 on the performance of the Bi2WO6 photocatalyst

In recent years, nonprecious metallic Bi with the surface plasmon resonance (SPR) effect has attracted the attention of researchers in the field of photocatalysis and has been loaded onto the surface of various photocatalytic materials to study its effect on photocatalytic activity. In this work, the internal and surface of Bi 2 WO 6 nanomaterials were modified by cleverly using the chelating and reducing properties of ethylene glycol (EG) to obtain photocatalytic materials with different metallic Bi modifications. A comprehensive analysis showed that modified Bi-BWO with a uniform distribution of metallic Bi was obtained by in situ etching on the surface of Bi 2 WO 6 nanosheets, and the SPR effect of metallic Bi can be used to expand the light absorption range and improve the separation and migration efficiency of electrons and holes. Under simulated sunlight irradiation, the Bi-BWO sample achieved 100% degradation of a Rhodamine B (RhB) solution within 30 min, which was 25% higher than that of the unmodified sample. Bi 0 inside the crystal structure caused lattice defects and served as a complex centre for photogenerated carriers, which decreased the photocatalytic efficiency. This study investigated the modification of different parts of photocatalytic materials with metallic Bi to introduce contrasting effects, developed a solution for in situ etching on the surface of modified bismuth-based photocatalytic materials, and provided a new idea to improve photocatalytic materials with cavities as the main active species. The metallic Bi and oxygen vacancies on the surface of the catalyst enhances the optical response of Bi 2 WO 6 and the separation of carriers. The internal Bi 0 becomes an electron trap, which inhibits the photocatalytic activity. • Metallic Bi defects and oxygen vacancies were etched on the surface or inside of Bi 2 WO 6 . • The surface metallic Bi promoted the photocatalytic activity, while the internal metallic Bi defects had the opposite effect. • SPR effect of surface metallic Bi and oxygen vacancy expanded the optical response range, adjusted the energy band structure, and promoted carrier migration. • The internal Bi defect became the electron capture centre and enhanced carrier recombination.