In situ constructed Bi/BiOBr nanoflower for synergistic H2O2 generation and pollutant degradation: coupling built-in electric field with SPR effect and environmental risk assessment

Abstract

Norfloxacin (NOR) pollution in water threatens ecosystems and human health by promoting antibiotic resistance. Bismuth oxybromide (BiOBr) degrades organics under light but suffers from low charge separation and light utilization, limiting practical antibiotic remediation. In situ constructed Bi/BiOBr nanoflower (BBOB-5) synergize built-in electric field and surface plasmon resonance (SPR) effect to achieve 100% NOR degradation within 20 min under visible light with a rate constant of 0.2063 min⁻¹. In addition, BBOB-5 outperforms BiOBr in photocatalytic pollutant removal and hydrogen peroxide (H₂O₂) production due to its unique structure and synergistic effects. The system enhances charge separation and “hot electron” generation, validated by electron spin resonance (ESR) and density functional theory (DFT) analyses, while reducing ecotoxicity via defluorination pathways. BBOB-5 demonstrates robust photocatalytic performance in real natural water bodies (lake, river, and seawater), retaining 80% efficiency after five cycles via scalable synthesis, reducing environmental risks without resource recovery claims. Ecotoxicity assessments and wheat seed bioassays show significantly reduced toxicity of degradation intermediates, aligning with environmentally friendly principles. This work advances plasmonic-electric field photocatalysts, enabling high-performance antibiotic degradation coupled with the beneficial in situ generation of H₂O₂, thereby offering a sustainable paradigm for efficient wastewater purification and environmental risk mitigation.