Systematic study of the stability of immobilized inorganic redox-probes on carbon electrodes

by Kilyanek, Stefan M.; Abshier, Joseph; Hallett, Lily; Lea, Mackenzie; Momand, Bilal; Spence, Sarah K.

The long-term chem. stability of inorganic complexes conjugated to carbon electrodes is critical to a variety of applications including the immobilization of well understood homogeneous electrocatalysts. The goal of this work is to find the windows of chem. and electrochem. stability in which the bond between a redox active complex such as Ru(terpy)22+ and the electrode surface can survive. A variety of linking functionalities including quinone, amine, and triazole moieties between the inorganic complex and the electrode surface were probed. From the stability studies performed, it has been shown that the bond between the electrode surface and 4'-(3,4-Dihydroxyphenyl)-2,2':6',2"-terpyridine is robust in chem. environments from pH 3.5 to pH 8, and that it can withstand potential cycling and survive for extended time periods at constant potentials, as long as the potential window is more cathodic than 0.2 V vs. Ag/AgCl saturate KCl. Studies of the other linking groups will be discussed.