Single-atom catalysts integrated with semiconductors for constructing a dual-potential electrochemiluminescence sensor for intracellular H2O2 detection

Abstract

Single-atom catalysts (SACs) have emerged as a new type of optoelectronic material prized for their atomic efficiency, unique electronic structures, and enzyme-like activity. Two-dimensional (2D) materials like graphitic carbon nitride (g-C₃N₄) serve as ideal substrates for anchoring SACs, owing to their abundant nitrogen coordination sites, tunable electronic properties, and excellent chemical stability. Here, we propose a novel composite catalyst, MoS₂/Co-C₃N₄, constructed by anchoring single cobalt atoms onto g-C₃N₄ and coupling with MoS₂. The formation of S–Co–N bonds provides efficient electron transfer channels, significantly enhancing electrochemiluminescence (ECL) emission of the luminol–H₂O₂ system in neutral media as well as realizing dual-potential ECL. This system enables selective H₂O₂ activation and reactive oxygen species (ROS) generation at −1.0 V, promoting both electrooxidation and ROS-driven ECL emission. Density functional theory (DFT) calculations were performed to elucidate the mechanism. An ECL sensor has been constructed and achieved sensitive intracellular H₂O₂ detection in HepG2 cells, demonstrating its promising potential for bioanalytical applications. This is the first time SACs/2D semiconductor composite materials have been applied for enhancing ECL emission, opening a new avenue for investigating the electrochemical properties of SACs/2D semiconductor composites.