Enhanced photocatalytic properties in BiOBr nanosheets with dominantly exposed (102) facets

Through first-principles computations, we compared the photocatalytic properties of (102) and (001) facets within BiOBr. Due to the surface states, the (102) facets of BiOBr have lower conduction band minimum and higher valence band maximum, compared with the (001) facets. Therefore, the (102) facets have more efficient electron injection, higher redox potential of photoinduced hole, and smaller band gap, which may result in better photocatalytic performances. Also, we prepared BiOBr-102 and BiOBr-001 samples with dominantly exposed (102) and (001) facets, respectively, and found red-shift absorption, and enhanced photodegradation rate of Rhodamine B in BiOBr-102, which agree well with the computations. Therefore, BiOBr samples with dominantly exposed (102) facets are superior in photocatalysis, and the results demonstrate the critical role of facet orientation in photocatalyst design.