Enhanced Potential-Resolved Luminol Electrochemiluminescence by the Catalyzing Oxygen Reduction Reaction on...

The efficient activation of molecular oxygen to generate reactive oxygen species (ROS) offers great promise for achieving potential-resolved electrochemiluminescence (ECL) in the luminol/O₂ system, though it typically relies on sophisticated catalysts. In this work, we demonstrate that carbonized polydopamine nanospheres (C-PDANSs) serve as an effective metal-free electrocatalyst to enhance the oxygen reduction reaction (ORR), thereby enabling the potential-resolved ECL of luminol. Mechanistic studies indicate that the ORR catalyzed by C-PDANSs proceeds via a two-electron pathway, yielding both superoxide radicals (O₂^-•) and hydrogen peroxide (H₂O₂). This ORR behavior facilitates the generation of sufficient ROS, which significantly boosts both cathodic and anodic luminol ECL, leading to 11.6-fold and 5.1-fold intensity enhancements, respectively. Based on the dual-potential ECL response, a ratiometric sensing platform was constructed for the detection of alkaline phosphatase (ALP). This study not only presents a different electrocatalyst for regulating dual-potential luminol ECL but also opens the avenue for designing biosensing schemes.