Morphology-dependent photocatalytic and photoelectrochemical performance of bismuth oxybromide crystals applied to malachite green dye degradation

Bismuth oxybromide (BiOBr) has received notable attention as a possible active solar photocatalyst with rationally high catalytic yield, although it still requires further alteration to enhance the photocatalytic activity. In this work, the BiOBr microstructures are synthesized in a controlled manner using two bromide sources, i.e., ammonium bromide (NH4Br) and cetyltrimethylammonium bromide (CTAB), which has been found to have a significant effect on the architecture of the BiOBr photocatalyst. CTAB induces the formation of 3D spherical hierarchical microflowers with curved nanoflakes, while NH4Br results in the formation of 3D flower-like open petal structures. The nature of final BiOBr products which were synthesized with different bromide sources is studied by their photo-electrocatalytic performances with a series of analytical techniques. The CTAB-assisted synthetic BiOBr sample (BiOBr-CT) showed the best photocatalytic and photoelectrochemical activities compared to NH4Br-assisted BiOBr (BiOBr-NH). BiOBr-CT shows a rate constant of 0.057 min−1 for the degradation of malachite green dye which is mostly used in the textile industry.