Wavelength-dependent differences in photocatalytic performance between BiOBr nanosheets with dominant exposed (0 0 1) and (0 1 0) facets

•Photoactivity of BiOBr nanosheets depends on exposed facets ((0 0 1) or (0 1 0)).•Photoactivity of BiOBr nanosheets depends on nanosheet thickness.•BiOBr-(0 1 0) exhibits higher visible-light photoactivity than BiOBr-(0 0 1).•BiOBr-(0 0 1) exhibits higher photoactivity than BiOBr-(0 0 1) under low-λ light.

BiOBr nanosheets with dominant exposed (0 1 0) facets exhibit higher photocatalytic activity than those with highly exposed (0 0 1) facets under illumination of light with wavelengths (λ) of ∼365 and ≥420 nm, but lower photoactivity under light with λ of 254 nm. The λ-dependent differences in photocatalytic activity result from different (0 0 1) facet exposure percentages (F(0 0 1)) and nanosheet thicknesses (H) between the two samples. Whether the difference in F(0 0 1) or that in H influences the photoactivity of the BiOBr nanosheets as a primary factor depends on incident light penetration depth which increases with the λ. This study gives a better insight into the structure-performance relationship of two-dimensional (2D) photocatalysts and will supply important direction for photocatalytic studies of 2D semiconductors.

Graphical abstractBiOBr nanosheets with dominant exposed (0 1 0) facets exhibits higher photocatalytic performance under light with λ of ≥420 nm but lower with λ of ∼254 nm than those with highly exposed (0 0 1) facets, which results from different exposed facets and thicknesses between the two nanosheets.Figure optionsDownload full-size imageDownload as PowerPoint slide