Construction of PDIsa/BiOBr type-I scheme heterojunction for efficient ciprofloxacin photocatalytic degradation.

Abstract

Fabrication of heterojunction photocatalysts is a promising strategy for enhancing photocatalytic activity. However, the study about traditional type-I heterojunction still remains to be developed. Herein, a PDIsa/BiOBr traditional type-I heterojunction was constructed by electrostatic self-assembly method, which owned improved light absorption capacity and photogenerated charge separation efficiency. The interfacial electric field and the polarization electric field of PDIsa impelled the separation of excitons. The degradation rate of ciprofloxacin (CIP) was improved by 3.2 times over the optimal PDIsa/BiOBr composite than pure BiOBr. In addition, the TOC removal efficiency reached 67.34% within 120min. Trapping experiments and electron spin resonance (ESR) tests showed that superoxide radical (•O2-) was the most active species, and singlet oxygen (1O2) and hole (h+) played a secondary role. The work may furnish a new reference for designing BiOBr-based type-I heterojunction.