Dynamic Control of Counter-Electrode Redox Reactions by Engineered Working-Electrode Materials for Boosted...

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Traditionally, electrochemiluminescence (ECL) mechanisms attribute activity solely to the working electrode (WE), considering the counter electrode (CE) inert.
• Existing ECL systems often face limitations in efficiency and sensitivity due to this unidirectional electrode activity.

Purpose of the Study:

• To fundamentally challenge the conventional paradigm of ECL by demonstrating the active role of the CE.
• To explore the synergistic effect of interelectrode coupling in enhancing ECL performance.
• To develop a novel ECL platform for ultrasensitive analyte detection.

Main Methods:

• Utilized single/dual-atom iron-doped hollow carbon spheres (Fe-HCS-T) as coreactant accelerants in a luminol-dissolved oxygen (DO) system.
• Employed spatially- and potential-resolved ECL mapping, radical-quenching studies, and electrochemical analyses.
• Investigated the modulation of interfacial potential at the CE and catalysis of reactive oxygen species (ROS) at the WE.

Main Results:

• Demonstrated that Fe-HCS-T triggers luminol electro-oxidation at the CE, alongside ROS formation at the WE.
• Revealed a synergistic WE-CE coupling mechanism, enabling high-efficiency ECL at a low potential (0.025 V).
• Achieved ultrasensitive detection of Trolox over a wide dynamic range (0.1 nM–10 mM) by leveraging the interelectrode coupling effect.

Conclusions:

• The study fundamentally challenges the traditional view of CE inertness in ECL systems.
• Interelectrode coupling is identified as a powerful strategy to significantly boost ECL performance.
• The developed Fe-HCS-T platform offers advanced sensing capabilities with enhanced efficiency and sensitivity.