Energy level mediation of (BiO)2CO3 via Br doping for efficient molecular oxygen activation and ciprofloxacin photodegradation

Solar-driven molecular oxygen activation is of great importance for reactive oxygen species (ROS) production in environmental remediation. In this work, a convenient bromine doping strategy was developed to mediate the energy level of Bi 2 O 2 CO 3 for molecular oxygen activation. The band structure and DFT calculation demonstrate that the Fermi level of Bi 2 O 2 CO 3 elevates after bromine doping, which promotes the molecular oxygen activation and ROS production. The Br-doped Bi 2 O 2 CO 3 exhibits remarkably enhanced photocatalytic ability and could degrade 95% of the ciprofloxacin within 30 min. Moreover, HPLC-MS analysis elucidates that the pyrrolidone ring degradation process is the dominate pathway in ciprofloxacin degradation over Br-doped Bi 2 O 2 CO 3 , resulting in the decrease of antimicrobial activity of the degradation products and the risk of drug-resistance. This work not only provides a molecular oxygen activation strategy via energy level mediation, but also helps us to further understand the relationship between the elemental doping and molecular oxygen activation.