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.