Mannitol ligand-assisted assembly of BiOBr photocatalyst in the cationic micelles of cetylpyridinium bromide

• Ligand-assisted assembly of BiOBr photocatalyst with mannitol as the complexing agent is proposed
• Complexation of Bi3 + limits the formation of BiO+ and controls crystal growth.
• Surface area was double that of the control and it activated O2 at triple the rate.

This is the first report on ligand-assisted assembly of BiOBr. BiOBr, using cetylpyridinium bromide (CPB) as Br source and surface template, was prepared with water with the presence of three polyhydroxyl alcohols. Based on SEM, HR-TEM and XRD, mannitol results in different particle morphologies. Rather than smooth microspheres, projections form that double surface area. BiOBr prepared in mannitol displayed the highest photocatalytic activity and tripled the oxygen consumption rate compared to the other preparations. The Bi3 +–mannitol complex competes with hydroxide for Bi3 + in the CPB micelles and limits the availability of BiO+, altering the assembly process. A four-step mechanism for ligand-assisted assembly of BiOBr in mannitol is proposed.

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