Dual halogen layers diversify band engineering in Sillén oxyhalide photocatalysts: electronic structure control of SrBi3O4X3 (X = Cl, Br, I) via halogen substitution

Abstract

Halogen substitution from X = Cl to Br or I in a Sillén oxyhalide SrBi₃O₄X₃ with single/double halogen layers results in both narrower bandgaps and more negative conduction band edges for various reduction reactions. This band tuning is achieved as the two halogen layers play distinct roles in shifting the band edges, offering a new strategy for band engineering in Sillén oxyhalides.