COFs@BiOI Z‐Scheme Heterojunctions for Efficient Visible‐Light‐Driven Removal of Tetracycline and Oxytetracycline

ABSTRACT In this work, we constructed two composite photocatalysts, COF‐C ₄ N@BiOI‐55 and COF‐TpMA@BiOI‐55, by a solvothermal method for visible‐light‐driven removal of tetracycline (TC) and oxytetracycline (OTC). Compared with pristine BiOI and the corresponding covalent organic frameworks (COFs), both composites exhibited markedly enhanced degradation rate under visible‐light irradiation for 90 min (TC: 96.1% for COF‐C ₄ N@BiOI‐55 and 95.1% for COF‐TpMA@BiOI‐55; OTC: 93.8% for COF‐C ₄ N@BiOI‐55 and 94.8% for COF‐TpMA@BiOI‐55). Structural characteristics indicated that the BiOI crystalline phase was well preserved after hybridization and that strong interfacial interaction is established. The improved photoelectrochemical properties suggested suppressed charge recombination, along with promoted interfacial transfer and separation of photogenerated carriers. Reactive‐species identification confirmed ∙O ₂ ⁻ as the dominant species, while ∙OH and h ⁺ contributed synergistically to the oxidation process. Work‐function analysis together with XPS evidence demonstrated electron enrichment on BiOI and a built‐in potential that promotes directional charge transfer. A Z‐scheme‐like charge‐transfer channel is proposed. Overall, an interfacial‐engineering strategy is proposed for constructing COFs/BiOI heterojunctions for the enhanced photocatalytic degradation of tetracycline antibiotics.