Electrocatalytic Effects of Au Nanoclusters in Its Electrochemiluminescence Enhanced by Coreactant Tertiary Amines

Atomically precise metal nanoclusters are increasingly exploited in electrocatalysis such as water electrolysis and CO2 reduction. The catalytic effects are generally evaluated by conventional electrochemical methods or end-product analysis. Herein, near infrared electrochemiluminescence (ECL) of the nanoclusters is introduced as a new signaling mechanism to complement classical voltammetric analysis for elucidating essential electrocatalytic parameters. Coreactant ECL from an aqueous soluble Au22 nanocluster (NCs) enhanced by a common pH buffer materials 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and by a piperazine drug hydroxyzine (HDZ) is studied under oxidative reduction pathways. Foot of the wave analysis on voltametric features and the kinetics profiles in potential-step experiments are studied in different nanocluster and coreactant concentrations. Benchmark parameters such as rate constants are determined under EC (Electron-transfer-Chemical-reaction) mechanism as feasibility validations. Because the luminescence properties of AuNCs are sensitive to the surface ligands or adsorbents, ECL is proposed as a new signal readout for operando studies providing insights for governing reaction mechanism and kinetics during catalytic reactions. Retrospectively, mechanistic understanding of the complex multi-step reactions during ECL generation can provide guidance for the evaluation and optimization of ECL property for better quantitative applications. As shown in the TOC, electrochemiluminescence (ECL) of the nanoclusters is introduced as a new signaling mechanism for elucidating essential electrocatalytic parameters and to complement foot of the wave analysis on voltametric current features. ECL provides kinetic insights during catalytic reactions for operando studies. Retrospectively, mechanistic understanding of the multi-step ECL reactions offer guidance for the evaluation and optimization of ECL property.+ image