Photocatalytic activity of AgBr/TiO2 in water under simulated sunlight irradiation

In this paper, the synthesis of AgBr/TiO₂ catalyst and the photocatalytic activity in water under simulated sunlight irradiation were studied. The influence of AgBr content in catalyst and the incident light intensity on the degradation of methyl orange (MO) was investigated. It was found that the initial reaction rate constant was dependent on the relative levels of AgBr content and incident light intensity, ranging between 0.008 min^?1 and 0.023 min^?1. At higher levels of AgBr content (>9 wt%), MO degradation was exclusively dependent on the incident light intensity, which implied that the excessive AgBr in catalyst had negligible effect on catalyst activity. However, at lower AgBr contents, the reaction rate increased with the increase of incident light intensity, and eventually reached a plateau level, indicating that the degradation of MO was limited by AgBr content. The results from powder X-ray diffraction (XRD) analysis showed that more than 80% of AgBr remained intact after 14 h of irradiation, although metallic silver was also detected.