Cathodic electrochemiluminescence and reversible electrochemistry of [Ru(bpy)3]2+/1+ in aqueous solutions on tricresyl phosphate-based carbon paste electrode with extremely high hydrogen evolution potential

摘要

Many cathodic electrochemiluminescence (ECL) systems require very negative potentials; it is difficult to achieve stable cathodic ECL in aqueous solutions because of hydrogen evolution and instability of intermediates. In this study, tricresyl phosphate-based carbon paste electrode (CPE) was used to achieve cathodic ECL. It exhibits no obvious hydrogen evolution even at a potential up to −1.6 V and dramatically stabilizes electrogenerated [Ru(bpy)3]+. Therefore, a reversible wave of [Ru(bpy)3]2+/1+ in aqueous solutions at carbon electrode has been observed for the first time, and cathodic ECL of [Ru(bpy)3]2+/S2O 8 2− has been achieved. Under the optimum conditions, the plots of the ECL versus the concentration of S2O 8 2− are linear in the range of 10−6 to 10−2 M with the detection limit of 3.98 × 10−7 M. Common anions have no effect on the ECL intensity of the [Ru(bpy)3]2+/S2O 8 2− system. Since CPEs have been widely used, CPEs with high hydrogen evolution potential are versatile platforms for electrochemical study and cathodic ECL study.