Vacancy Engineering of Nickel Single-Atom Catalysts to Enable Low-Triggering-Potential Electrochemiluminescence of...

The electrochemiluminescence (ECL) instability of graphitic carbon nitride (CN) caused by electrode passivation at a triggering potential exceeding -0.9 V has been widely recognized. Although doping, heterostructure, and vacancy engineering have been attempted to mitigate the electrode passivation of CN, achieving a strong ECL of CN at a potential of no more than -0.9 V remains a formidable challenge. This work innovatively developed nitrogen vacancy (Nv) engineering of nickel single-atom catalysts (Ni SACs) to enable ECL emission of CN at -0.9 V without any exogenous coreactants. The introduction of rich Nv on CN not only promoted the electrochemical reduction of CN but also adjusted the coordination environment of Ni single atoms (Ni_SA) to form a Ni-N₆ coordination structure. Theoretical calculation revealed that the Ni-N₆ structure effectively reduced the energy barrier of the oxygen reduction pathway and activated dissolved oxygen to produce a large number of reactive oxygen species (ROS), thus significantly promoting ECL emission and reducing the ECL potential of CN. As a proof of concept, Ni_SA-Nv-CN was applied for sensitive ECL detection of the cancer biomarker flap endonuclease 1 (FEN1) with the aid of a multipath-activated CRISPR/Cas12a amplification strategy. Nv engineering of SACs provides a new thought to solve the electrode passivation of CN.