Construction of Bi2O2CO3/Bi2O2SiO3 Z-scheme heterojunction and interfacial electron transfer mechanism for photocatalytic degradation of ciprofloxacin

Abstract

To address the recalcitrant nature of ciprofloxacin (CIP) in aquatic systems, flower-like Bi₂O₂CO₃/Bi₂O₂SiO₃ (BOC/BOS) Z-scheme heterojunction photocatalysts were synthesized by hydrothermal method, and the relationship between structure and properties was systematically studied. The successful construction and morphological characteristics of the heterojunction were confirmed by XRD and SEM characterization. Optical performance tests show that the energy band regulation at the BOC/BOS heterojunction interface significantly broadens the light absorption range of the material and optimizes the visible light response capability. Under visible light irradiation for 180 min, the removal rate of CIP by the optimized BOC/BOS reached 90.02 %. Active species capture experiments and energy band analysis revealed that the Z-scheme heterojunction not only effectively inhibited the recombination of photogenerated carriers through the interface electron-hole recombination path, but also confirmed that superoxide radicals (•O₂⁻) were the main active substances in the degradation process. This study provides a new strategy for the design of photocatalyst based on bismuth-based heterojunction, and reveals its application potential in the treatment of refractory antibiotic wastewater.