The utilization of an elaborate nanomaterial is still a prevalent method to generate luminol electrochemiluminescence (ECL). Herein, we report on the multimodal generation of anodic and cathodic luminol ECL through a metal-free nanomaterial. This nanomaterial was prepared by covalently grafting 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on the surface of multi-walled carbon nanotube (MWCNT). TEMPO-MWCNTs modified electrode exhibit high electrocatalytic activities toward H2O, luminol, H2O2 and O2 during the oxidation/reduction processes. Such electrocatalysis has not only resulted in significant enhancement of luminol ECL, but also enabled the generation of three ECL peaks in luminol/O2 system and two ECL peaks in luminol/H2O2 system on the electrode via different pathways. The natures of these ECL peaks are also revealed through the spooling ECL spectra. Furthermore, an ECL sensor has been designed for sensitive detection of an organophosphorus pesticide (OP) based on the enhanced ECL of luminol/H2O2 system. Therefore, this work suggests that nitroxyl radical functionalized carbon nanomaterial can be used as a new electrocatalyst for studying luminol ECL in the presence of either an endogenous or exogenous co-reactant.
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