Molybdenum disulfide quantum dots as dual-functional catalysts and coreactants for enhanced Ru(bpy)₃²⁺...

Electrochemiluminescence (ECL) is a powerful tool for clinical diagnosis due to its exceptionally sensitive characteristics. In this work, enhanced and stable anodic ECL was observed in the suspension of hydrothermally synthesized molybdenum disulfide quantum dots (MoS₂ QDs) and ruthenium(II) tris(2,2'-bipyridyl) (Ru(bpy)₃²⁺), which was enhanced more than 80-fold compared to that of individual Ru(bpy)₃²⁺. MoS₂ QDs can effectively catalyze the oxidation of Ru(bpy)₃²⁺, with amino groups on their surface serving as coreactants. As a result, MoS₂ QDs exhibit high efficiency comparable to tripropylamine (TPrA) for the ECL of Ru(bpy)₃²⁺. The possible mechanism of the electrode surface reaction was discussed, while several factors including the pH of the buffer solution and the amount of MoS₂ QDs were also investigated, to further confirm the role of MoS₂ QDs in the Ru(bpy)₃²⁺/MoS₂ QDs system. Based on the quenching effect between the excited state of Ru(bpy)₃²⁺ in the Ru(bpy)₃²⁺/MoS₂ QDs ECL system and the oxidized form of dopamine (DA), a DA sensing platform was successfully established, and the DA content in urine was successfully detected (recovery rate: 95.90-101.13%).