Modulation of electron transfer in electrochemiluminescence: synergistic utilization of doping effects in the material and composite effects of Au in the core–shell structure

Abstract

Elucidating the electron transfer mechanism and its regulatory strategy in the electrochemiluminescence (ECL) phenomenon is undoubtedly a challenging task. In this paper, when characterized using cyclic voltammetry, we found that modifying the catalyst significantly affected the electron transfer efficiency of reactive oxygen species (ROS, e.g. O₂˙⁻) generation, and consequently the electron transfer of luminol. The effect is more significant than the addition of reactant H₂O₂. Thus modifying the catalyst becomes a more effective way to influence the ECL. In addition, thanks to the fact that Au/SiO₂:0.6% Mn@MnO possesses the composite effect of Au in the core–shell structure, the material was able to be used as an efficient negative catalyst, which ultimately led to the preparation of a more effective ECL quencher than SiO₂:0.6% Mn. The material can achieve ECL quenching of luminol by reducing the electron transfer required for ROS generation during electrocatalysis, which in turn improves the detection performance and stability of the sensors. Based on these findings, we constructed a dual-strategy ECL quenching system for the highly sensitive detection of carcinoembryonic antigen (CEA). This not only opens up a new research direction for ECL technology in weakly alkaline media, but also further extends the application of ECL technology in biological applications.