An electrogenerated chemiluminescence (ECL) system by in situ coreactant production, where Ru(bpy)3 2+ emission is generated at a boron-doped diamond (BDD) electrode, is presented. The system takes advantage of the unique properties of BDD to promote oxidation of carbonate (CO3 2-) into peroxydicarbonate (C2O6 2-), which further reacts with water to form hydrogen peroxide (H2O2), which acts as a coreactant for Ru(bpy)3 2+ ECL. Investigation of the mechanism reveals that ECL emission is triggered by the reduction of H2O2 to hydroxyl radicals (OH•), which later react with the reduced Ru(bpy)3 + molecules to form excited states, followed by light emission. The ECL signal was found to increase with the concentration of CO3 2- therefore, with the concentration of electrogenerated H2O2, although at the same time, higher concentrations of H2O2 can quench the ECL emission, resulting in a decrease in intensity. The carbonate concentration, pH, and oxidation parameters, such as potential and time, were optimized to find the best emission conditions.
ASJC Scopus subject areas
- Colloid and Surface Chemistry