Intramolecular Switching Oxygen Reduction Reaction Driven by Dual‐Crystalline Bimetallic MOF induces Self‐Potential‐Resolved Electrochemiluminescence Biosensor

Abstract Framework materials, particularly metal–organic frameworks (MOFs), have emerged as versatile platforms for multifunctional applications due to their tunable structures and properties. In this study, a series of bimetallic ZnRuMOFs with dual‐crystalline phase structure was designed and synthesized. This unique dual‐crystalline bimetallic MOF configuration enables intramolecular autocatalysis and selective oxygen reduction reaction (ORR). By utilizing endogenous dissolved O 2 as a green co‐reactant, an electrochemiluminescence (ECL)‐coupled ORR system with potential‐resolving capability was developed. Experimental results, supported by density functional theory (DFT) calculations, elucidated the ability of MOFs with different phase structures to catalyze specific reactive oxygen species (ROS) generation and the mechanism of ECL luminescence mediated by intramolecular autocatalysis using ZnRuMOF as the luminophore. The selectively generated ROS function as intramolecular coreactants, reducing radical transfer losses and significantly enhancing ECL stability. Leveraging these findings, a novel potentiometrically resolved ECL biosensor for the cardiovascular disease biomarker microRNA 24 was constructed. The biosensor integrates ROS‐mediated intramolecular modulation with a platinum single‐atom catalysts (Pt‐N‐SAC). This study demonstrates that precise modulation of MOF structures reveals distinct catalytic properties associated with different MOF configurations, offering a new strategy for the development of simple yet efficient monoluminescent ECL systems.