Synergistic photocatalysis-catalytic peroxidation of BiOBr/H₂O₂ system for 4-chlorophenol degradation

The synergistic BiOBr/H₂O₂ system was developed to improve the visible-light photo-degradation activity of 4-chlorophenol (4-CP). It was demonstrated that the BiOBr catalyst could decompose H₂O₂ molecular efficiently under visible light irradiations. Based on the trapping test, the main active species of ⋅O₂ ⁻ radicals in BiOBr/H₂O₂ system accelerated the efficient decomposition of H₂O₂ to form the ⋅OH radicals, which further reacted with the 4-CP. In comparison, the photo-induced holes were the main active species during the photo-degradation of 4-CP on the single BiOBr catalyst. Furthermore, the intermediate of both benzoquinone and hydroquinone during the 4-CP photo-degradation in the BiOBr/H₂O₂ system, was determined by the HPLC-MS measurement, which was followed by the final decomposition to CO₂. In addition, the high crystallization resulted in the stability of BiOBr in the BiOBr/H₂O₂ system, indicative of the potential practical application for the wastewater treatment.