Facet-dependent in-situ formation of oxygen vacancy and plasmonic Bi in BiOBr nanosheets and resultant influence on the generation and separation of charge carriers

The development of advanced photoactive materials has aroused widespread interest, but is severely plagued by the inherent narrow photo-responsive range and rapid recombination of electrons and holes. In this study, the unconventional BiOBr nanosheets decorated with Bi0 and oxygen vacancies (OVs) are successfully synthesized through a facial one-pot hydrothermal method, followed by heat treatment. Cetyltrimethylammonium bromide and mannitol contribute to the selective exposure of (001) and (010) facets, respectively. The absence of the outermost Br atoms facilitates the simultaneous generation of OVs and Bi0 on the surface during heating, forming the Schottky junction. The synergy of SPR in the Bi0 metal, OVs and Schottky junction can effectively enhance the light absorption and charge separation. This work proposes and verifies a feasible approach to construct defects in-situ by regulating the crystal facets and manipulating the surface atomic arrangement and coordination.