Synergistic Defect and Interface Engineering in PANI-Bridged CeO₂/BiOI Dual Z-Scheme Heterojunction for Efficient...

Tetracycline antibiotics pose persistent ecological risks, underscoring the urgent need for sustainable remediation strategies. Bismuth oxyiodide (BiOI) is attractive for photocatalysis owing to its visible-light responsiveness, yet its narrow band gap (1.8 eV) and rapid charge recombination hinder efficiency. Here, a ternary CeO₂/BiOI/PANI heterostructure was fabricated via hydrothermal synthesis and in situ polymerization. The design exploits Ce³⁺/Ce⁴⁺ redox cycling to generate oxygen vacancies, establishes a dual Z-scheme heterojunction among CeO₂, BiOI, and PANI to preserve high redox potentials, and leverages PANI's π-conjugated framework to accelerate interfacial electron transfer. These synergistic effects narrow the band gap to 1.30 eV, suppress photoluminescence by 75%, and markedly reduce interfacial resistance, thereby enhancing charge separation and migration. The optimized composite achieved 92% tetracycline degradation within 120 min under visible light─approximately double that of pristine BiOI─and retained 79% activity after five cycles, demonstrating excellent stability. Radical quenching and band structure analyses confirmed a dual Z-scheme charge transfer pathway. This work provides a robust strategy for constructing organic-inorganic heterostructures toward efficient photocatalytic degradation of antibiotics and other recalcitrant pollutants.