Engineering directed charge transport pathway in MOF@COF hetero-framework for enhanced singlet oxygen production and tetracycline photo-oxidation

The persistence of tetracycline antibiotics in aquatic environments poses significant harm to both ecological systems and public health. In this study, a Cu-MOF-74@TAPT-DHTA-COF hetero-framework was designed by constructing interfacial Cu-N/O coordination bonds, which create efficient electron transfer pathways that enhance charge separation and migration. Mechanistic investigation demonstrated that the molecular oxygen adsorption and activation was enhanced by this interfacial coordination engineering, promoting the selective production of singlet oxygen ( 1 O 2 ) and thus accelerating the photo-oxidation of tetracycline (TC). The hetero-framework achieved 91.5% TC removal within 60 min with apparent value of 0.03325 min⁻¹ . This constant is 2.0 times that of Cu-MOF-74 and 1.9 times that of TAPT-DHTA-COF. Toxicity evaluation confirmed effective reduction of ecological risks, with all final degradation products testing negative for mutagenicity. Furthermore, a photocatalytic membrane reactor based on the hetero-framework demonstrated nearly complete contaminant removal and exceptional stability in continuous-flow wastewater treatment, highlighting its practical applicability. This work elucidates the molecular-level mechanism of 1 O 2 generation boosted by the interfacial coordination engineering and provides novel design principles for advanced photocatalytic water treatment technologies.