Photo-induced dye-sensitized BiPO4/BiOCl system for stably treating persistent organic pollutants

An enhanced dye (rhodamine B, RhB)-sensitized BiPO4/BiOCl heterojunction (P-BOC) system was explored for simultaneously treating various highly concentrated hazardous organic pollutants, including dyes and persistent organic pollutants (POPs) (such as bisphenol A, BPA and 4-chlorophenol, 4-CP) under visible-light irradiation (> 420 nm). Such high photo-degradation activity of P-BOC system stemmed from the high-performance of sensitization of RhB upon visible-light excitation. Suitable conduction band match between BiPO4 and BiOCl in P-BOC heterojunctions readily facilitated the subsequent electron transfer from excited RhB to P-BOC surface, forming various reactive oxygen species (ROS). Superoxide radical (O2−) and hydrogen peroxide (H2O2) served as the main ROS species for oxidizing POPs. A possible enhanced RhB- photosensitizing degradation mechanism of P-BOC heterojunction was proposed for clarifying the efficient photo-degradation treatment of highly concentrated hazardous pollutants. The combination of dye-sensitization with P-BOC heterojunctions explored a green, energy saving, efficient photo induced system for treating pollutants.