Highlights
BiOBr nanomaterials with varying predominant crystal facets can be synthesized by changing the pH of the solvent medium.
The oxygen vacancies and porosity of the nanomaterials depends on the nature of predominant crystal facets.
BiOBr nanomaterials with predominantly exposed (001) crystal facet specifically show maximum catalytic activity.
Incorporation of Fe ions further improves the catalytic efficiency BiOBr nanomaterials.