<p>Photocatalysis is a promising alternative to conventional wastewater treatment technologies. BiOBr materials have been extensively investigated for photocatalytic degradation of Rhodamine B (RhB), yet research on morphology regulation and corresponding catalytic performance remains insufficient. In this study, BiOBr with distinct morphologies, including nanoflowers, nanosheets, and nanocoral-like nanostructures, was successfully synthesized through pH adjustment during solvothermal synthesis under identical experimental conditions. This morphology regulation simultaneously modified the thickness of BiOBr nanomaterials. Experimental results demonstrate that BiOBr nanosheets synthesized under weakly acidic conditions exhibit superior light absorption range and charge carrier separation efficiency compared to nanoflower and nanocoral-like counterparts. The BiOBr nanosheets synthesized at pH 6, with a rate constant 0.04977&#xa0;min⁻¹ exhibit excellent photocatalytic activity in the degradation of rhodamine B dye under visible light, higher than BiOBr nanoflowers and coral-like structures. This work provides fundamental insights into morphology-dependent photocatalytic mechanisms and proposes a practical strategy for developing efficient BiOBr-based photocatalytic degradation materials.</p> Graphical Abstract <p></p> <p>Photocatalytic mechanism of BiOBr nanoflowers under sunlight, showing charge separation, redox potentials, and pollutant degradation.</p>