Continuous singlet oxygen generation for persistent chemiluminescence in Cu-MOFs-based catalytic system

Due to the ultra-weak and instantaneous chemiluminescence (CL) of luminol-H₂O₂ system, developing new catalysts to dramatically enhance and produce persistent CL emission is crucial. In this study, the Cu-metal-organic frameworks (Cu-MOFs) with flower morphology converted from Cu-based metal-organic gels (Cu-MOGs) could catalyze luminol-H₂O₂ system, exhibiting persistent CL. The possible mechanism of this persistent emission of luminol was attributed to the gradual generation of OH˙, O₂˙^- and ¹O₂ in Cu-MOFs-catalyzed luminol-H₂O₂ system. In addition, OH˙ and O₂˙- were continuously recombined into singlet oxygen on the surface of Cu-MOFs which further prolonged the duration time of the CL leading to the persistent emission, due to the longer lifetime of ¹O₂ compared to OH˙ and O₂˙^-. Furthermore, based on the high-intensity emission of Cu-MOFs-catalyzed luminol-H₂O₂ system, the strategy for sensitive response to quercetin was established with good linearity within the range of 0.05-1.2 μM and a detection limit of 49.7 nM. This study provides a new idea for developing persistent CL catalysts.