Potential‐resolved electrochemiluminescence of Ru(bpy)₃²⁺/C₂O₄²⁻ system on gold electrode

Abstract

Abstract The electrogenerated chemiluminescence of Ru(bpy) 3 2+ /C 2 O 4 2− system on a pre‐polarized Au electrode was studied using a potential‐resolved electrochemiluminescence (PRECL) method. Two anodic ECL peaks were observed at 1.22 V (vs. SCE) (EP1), 1.41 V (vs. SCE) (EP2), respectively. The effects of the concentration of oxalate and Ru(bpy) 3 2+ , adsorbed sulphur, CO 2 , O 2 , pH of the solution and pretreatment of the Au electrode on the two PRECL peaks were examined. The surface state of the pre‐oxidized gold electrode was also studied using the X‐ray photoelectron spectroscopy (XPS) technique. Moreover, comparative studies on i–E and I–E curves were carried out and a possible mechanism involving both the catalytic and the direct electro‐oxidation pathways was proposed for the ECL of Ru(bpy) 3 2+ /C 2 O 4 2− system. EP1 is attributed to the Ru(bpy) 3 2/3+ reaction catalysed by C 2 O 4 2− to generate Ru(bpy) 3 2+* . EP2 is likely because C 2 O 4 2− was oxidized at the electrode to form CO 2 −· , followed by reaction with Ru(bpy) 3 3+ to generate Ru(bpy) 3 2+* . Copyright © 2002 John Wiley & Sons, Ltd.

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Identifiers

DOI

10.1002/bio.674

Journal

Luminescence

Year

2002