Journal of Electroanalytical Chemistry, Vol.495, No.2, 152-159, 2001
Electrocatalytic response of amino acids at Cu-Mn alloy electrodes
The anodic voltammetric responses obtained for ethylenediamine and representative amino acids in 0.10 M NaOH (> 0.5 V vs. SCE) are significantly larger at preanodized CuMn (95:5) and CuMn (90:10) rotated disk electrodes as compared to the responses at preanodized pure Cu electrodes. The larger response at the CuMn electrodes is demonstrated to result from increased values of the apparent number of electrons transferred (n(app)) and/or the apparent heterogeneous rate constants (k(app)) for the corresponding anodic reactions at these alloy electrodes. It is speculated that these effects are the result of enhanced adsorption of the reactant species at Mn-sites within the response mechanisms at the preanodized Cu-Mn electrode surfaces. We speculate further. that the Mn-sites. whose 3d-orbital occupancy is lower than that of Cu-sites, can adsorb the reactant species via the nonbonded electron pairs of their amine moieties in the alkaline media. The electrocatalytic benefit of adsorption is anticipated to come as a result of an increased lifetime of the reactant species within the applied interfacial potential at the electrode / solution interface.