Photodegradation of Rhodamine B and Bisphenol A Over Visible-Light Driven Bi₇O₉I₃-and Bi₁₂O₁₇Cl₂-Photocatalysts Under White LED Irradiation

Two different bismuth oxyhalides photocatalysts Bi₇O₉I₃ and Bi₁₂O₁₇Cl₂ were obtained by oil bath and hydrothermal methods. The micro/nano-structures obtained were characterized by XRD, SEM, DRS and XPS. The XRD patterns are identical to those already reported. SEM revealed the formation of hierarchical micro/nano structures for Bi₇O₉I₃ and nanobelts for Bi₁₂O₁₇Cl₂. Band gap values were determined for both catalysts from DRS and XPS data. The photocatalytic degradation of Rhodamine B and Bisphenol A were studied with both bismuth oxyhalides and compared with commercial titanium dioxide (TiO₂). As light source was used a white Light-Emiting Diode lamp. As expected, a poor photocatalytic degradation was obtained in presence of TiO₂, but significant drops of concentrations in presence of the bismuth oxyhalides was observed. However, the mineralization of both polluntants was higher in presence of Bi₁₂O₁₇Cl₂ than with Bi₇O₉I₃. In addition, a great part of Rhodamine B was removed by Bi₇O₉I₃ in the dark, which is attributed to its morphological features. In contrast, Bisphenol A was degraded under visible light irradiation without significant adsorption.