Co₃O₄/NiCo₂O₄ heterojunction as oxygen evolution reaction catalyst for efficient luminol anode...

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Luminol is a widely used electrochemiluminescence (ECL) reagent, but its efficiency is limited by reactive oxygen species (ROS) generation.
• Current methods for ROS generation face issues with biotoxicity, instability, and limited oxygen solubility, leading to insufficient ROS and low luminol luminescence.
• Efficient luminol anodic ECL systems are needed to overcome these limitations.

Purpose of the Study:

• To develop an efficient luminol anodic ECL system by creating a novel nanostructure.
• To investigate the role of oxygen evolution reaction (OER) intermediates and products in enhancing luminol ECL.
• To deepen the understanding of the relationship between ROS and luminol luminescence.

Main Methods:

• Utilized zeolitic imidazolate framework-67 (ZIF-67) as a template for synthesizing a ZIF-67/Ni-Co-layered double hydroxide (LDH) composite.
• Employed a controlled chemical etching method followed by annealing in air to form a Co3O4/NiCo2O4 double-shelled nanobox (DSNB) heterostructure.
• Investigated the electrocatalytic performance of the DSNB in the oxygen evolution reaction (OER) and its effect on the luminol ECL signal.

Main Results:

• The synthesized Co3O4/NiCo2O4 DSNB heterostructure exhibited excellent electrocatalytic activity for OER.
• Both OER intermediates and products directly participated in the luminol chemiluminescence process.
• A remarkable 700-fold increase in the ECL signal was observed compared to luminol alone.

Conclusions:

• Established a novel OER-mediated ECL system for enhanced luminol luminescence.
• Demonstrated the potential of Co3O4/NiCo2O4 DSNB heterostructures as efficient electrocatalysts in ECL applications.
• Provided new insights into the mechanism of luminol anodic ECL and its interaction with ROS.