Oxygen vacancy-promoted photocatalytic H₂O₂ production over bismuth oxybromide nanosheets

Hydrogen peroxide (H₂O₂) is an essential and versatile oxidant. The photocatalytic production of H₂O₂ is a promising alternative to the conventional anthraquinone oxidation process. In this work, BiOBr nanosheets with oxygen vacancies (OVs) were successfully synthesized by a solvothermal method in the presence of mannitol. The character of the nanosheets shortened the diffuse length of charge carriers, which is beneficial for the charge separation. The introduction of OVs enhanced the visible light absorption and also improved the carrier separation. Furthermore, OVs enhanced the activation of O₂ molecules and facilitated the generation of ˙O₂^-. As a result, the products exhibited good performance in photocatalytic H₂O₂ production. After introducing HCOOH, the yield of H₂O₂ was further enhanced by a factor of 50, from 3 μmol h^-1 to 150 μmol h^-1. This work provides a reference to design high performance photocatalysts for H₂O₂ production through defect engineering.